Water hammer compensator in internal water supply systems FAR. Water hammer compensators

(VT.CAR19.I) Membrane hydraulic shock absorber VT.CAR 19 is designed to compensate for pressure surges that occur when valves are suddenly opened or closed in residential water supply systems. The device also plays the role of an expansion tank, which receives the excess volume of water that occurs in the pipes during natural heating in the absence of water intake. The VT.CAR 19 water hammer compensator is a miniature tank made of AISI 304L stainless steel with an internal separating membrane made of EPDM elastomer. Small bulges on the membrane surface ensure its loose connection to the housing and the maximum contact area of ​​the membrane with the transported medium. The capacity of the hydraulic shock absorber VT.CAR 19 is 0.162 l, the factory setting of the pressure in the air chamber is 3.5 bar, the maximum operating pressure in the protected apartment water supply is 10 bar, the maximum pressure during water hammer is 20 bar, the maximum operating temperature is 100 ° C . Connecting thread diameter - 1/2". Dimensions (height x diameter) of the product - 112 x 88 mm. The factory setting provides protection for pipelines with a nominal working pressure of 3 bar. When using a compensator in systems with other parameters, the tank should be reconfigured in such a way that the pressure in the air chamber exceeded the nominal by 0.5 bar.

General information about water hammer

Water hammer is an abrupt change in the pressure of a fluid flowing in a pressure pipeline that occurs when a sudden change in flow velocity occurs. In a broader sense, water hammer is a rapid alternation of “jumps” and “dips” in pressure, accompanied by deformation of the fluid and pipe walls, as well as an acoustic effect similar to a hammer hitting a steel pipe. With weak hydraulic shocks, the sound manifests itself in the form of “metallic” clicks, however, even with such seemingly insignificant shocks, the pressure in the pipeline can increase quite significantly.

The stages of water hammer can be illustrated by the following example ( fig.1): let a single-lever tap or mixer be installed at the end of the apartment pipeline connected to the house riser (it is these mixers that allow you to shut off the flow relatively quickly).

Fig.1. Water hammer stages

When the valve is closed, the following processes occur:

  1. While the tap is open, the liquid moves through the apartment pipeline at a speed of " ν ". At the same time, the pressure in the riser and the apartment pipeline is the same ( p).
  2. When the valve is closed and the flow is abruptly decelerated, the kinetic energy of the flow is converted into the work of deformation of the pipe walls and the liquid. The walls of the pipe are stretched, and the liquid is compressed, which leads to an increase in pressure by an amount ∆p(shock pressure). The zone in which the pressure increase has occurred is called the shock wave compression zone, and its extreme section is called the shock wave front. The front of the shock wave propagates towards the riser at a speed of "c". Here I would like to note that the assumption of the incompressibility of water, adopted in hydraulic calculations, is not applied in this case, because real water is a compressible liquid with a volumetric compression ratio of 4.9x10 -10 1/Pa. That is, at a pressure of 20,400 bar (2040 MPa), the volume of water is halved.
  3. When the front of the shock wave reaches the riser, all the liquid in the apartment pipeline will be compressed, and the walls of the apartment pipeline will be stretched.
  4. The volume of liquid in the house system is much larger than in the apartment wiring, therefore, when the shock wave front reaches the riser, the excess fluid pressure is mostly smoothed out by expanding the cross section and turning on the total volume of liquid in the house system. The pressure in the apartment pipeline begins to equalize with the riser pressure. But at the same time, the apartment pipeline, due to the elasticity of the wall material, restores its original cross section, compressing the liquid and squeezing it into the riser. The zone of removal of deformation from the walls of the pipeline extends to the valve with a speed of " With».
  5. At the moment when the pressure in the apartment pipeline is equal to the original one, as well as the fluid velocity, the flow direction will be reversed ("zero point").
  6. Now the liquid in the pipeline with a speed of " ν ” tends to “break away” from the crane. There is a "shock wave rarefaction zone". In this zone, the flow velocity is zero, and the fluid pressure becomes lower than the initial one, which leads to compression of the pipe walls (diameter reduction). The rarefaction zone front moves to the riser at a speed of " With". With a significant initial flow rate, the vacuum in the pipe can lead to a decrease in pressure below atmospheric, as well as to a violation of the continuity of the flow (cavitation). In this case, a cavitation bubble appears in the pipeline near the valve, the collapse of which leads to the fact that the fluid pressure in the zone of the reflected shock wave becomes greater than the same indicator in the direct shock wave.
  7. When the compression front of the shock wave of the riser is reached, the flow velocity in the apartment pipeline is zero, and the liquid pressure is lower than the initial one and lower than the pressure in the riser. The walls of the pipeline are compressed.
  8. The pressure difference between the liquid in the riser and the apartment pipeline causes the liquid to enter the apartment pipeline and equalize the pressures to the original value. In this regard, the walls of the pipe also begin to acquire their original shape. Thus, a reflected shock wave is formed, and the cycles are repeated again until complete extinction. In this case, the time interval during which all stages and cycles of hydraulic shock pass does not exceed, as a rule, 0.001–0.06 s. The number of cycles can be different and depends on the characteristics of the system.

On rice. 2 the stages of water hammer are shown graphically.

Rice. 2. Graphs of pressure change during hydraulic shock.

Schedule on rice. 2a shows the development of hydraulic shock when the pressure of the liquid in the shock wave discharge zone does not fall below atmospheric pressure (line 0).

Schedule on rice. 2b displays a shock wave, the rarefaction zone of which is below atmospheric pressure, but the hydraulic continuity of the medium is not violated. In this case, the liquid pressure in the rarefaction zone is lower than atmospheric pressure, but no cavitation effect is observed.

Schedule on fig.2c displays the case when the hydraulic continuity of the flow is violated, that is, a cavitation zone is formed, the subsequent collapse of which leads to an increase in pressure in the reflected shock wave.

Varieties of hydraulic shocks and basic design provisions

Depending on the speed with which the shut-off device on the pipeline is closed, water hammer can be "direct" and indirect. "Direct" is called a shock, in which the flow overlap occurs in a time less than the shock period, that is, the condition is met:

T 3 ≤ 2L/c,

Where T 3 is the closing time of the locking organ, s; L- the length of the pipeline from the locking device to the point at which constant pressure is maintained (in the apartment - to the riser), m; With is the shock wave velocity, m/s.

Otherwise, the water hammer is called indirect. With an indirect impact, the pressure jump is much smaller in magnitude, since part of the flow energy is damped by partial leakage through the shut-off device.

Depending on the degree of flow blocking, the water hammer can be complete or incomplete. A complete blow is one in which the shut-off element completely blocks the flow. If this does not happen, that is, part of the flow continues to flow through the shut-off organ, then the water hammer will be incomplete. In this case, the difference in flow rates before and after shutoff will be the calculated velocity for determining the magnitude of water hammer. The magnitude of the pressure increase during direct full hydraulic shock can be determined by the formula of N.E. Zhukovsky (in Western technical literature, the formula is attributed to Alievi and Michaud):

Δp = ρ ν s, Pa,

Where ρ – density of the transported liquid, kg/m 3 ; ν is the speed of the transported fluid until the moment of sudden braking, m/s; With is the velocity of shock wave propagation, m/s.

In turn, the shock wave propagation velocity c is determined by the formula:

Where c 0- the speed of sound propagation in a liquid (for water - 1425 m / s, for other liquids can be taken according to tab. 1); D– pipeline diameter, m; δ – pipe wall thickness, m; E f is the bulk modulus of elasticity of the liquid (can be taken according to tab. 2), Pa; Eating is the modulus of elasticity of the pipe wall material, Pa (can be taken according to tab. 3).

Table 1. Characteristics of liquids


Table 2. Characteristics of pipe wall materials


If we take into account that the speed of water movement in apartment systems should not exceed 3 m / s (clause 7.6. SNiP 2.04.01), then for pipelines made of various materials, it is possible to calculate the magnitude of the pressure increase with a possible direct full hydraulic shock. Such summary data for some pipes are presented in tab. 3.

Table 3. Pressure increase during water hammer at a flow velocity of 3 m/s


Pipe material and dimensions

Shock wave speed, m/s

Δp, bar

Metal polymer

Polyethylene

Polypropylene

Steel (VGP normal pipes)

With indirect water hammer, the pressure increase is calculated by the formula:

IN tab. 4 the average response time of the main apartment fittings is given. For each type of this fitting, the length of the pipeline is calculated, more than which the water hammer ceases to be direct.

Table 4. The length of the direct impact section for water shut-off valves


Type of apartment fittings

Response time, s

Length of direct impact area, m

For non-metallic pipeline

For metal pipeline

Lever faucet or faucet

Shower switch (diverter)

Washing machine solenoid valve

Solenoid valve dishwasher

Anti-leak solenoid valve (1/2")

Toilet fill valve

Possible consequences of hydraulic shocks

In apartment networks, the occurrence of water hammer, of course, does not entail such large-scale destructive consequences as on large-diameter main pipelines. However, even here they can cause a lot of trouble and loss, if you do not take into account the possibility of their occurrence.

Periodically recurring hydraulic shocks in apartment piping can cause the following troubles:

– reduction of service life of pipelines. The normative service life of internal pipelines is determined by the totality of characteristics (temperature, pressure, time) in which the pipe is operated. Even such short-term, but often recurring, alternating pressure surges and dips that occur during hydraulic shock significantly distort the picture of the operational mode of the pipeline, reducing its trouble-free operation. To a greater extent, this applies to polymer and multilayer pipelines;

- extrusion of gaskets and seals in fittings and pipeline connectors. Elements such as piston pressure reducers, ball valves, valves and mixers with rubber gland rings, o-rings for compression and press connectors, as well as rings for half-strings (“American women”) are subject to this. In apartment water meters, extrusion of the sealing ring between the measuring chamber and the counting mechanism can lead to water entering the counting mechanism (Fig. 3);

Rice. 3. Water ingress into the counting mechanism of the water meter as a result of gasket extrusion

- even a single water hammer can completely disable the instrumentation installed in the apartment. For example, the bending of the pressure gauge needle from interaction with the restrictive pin is a clear sign of a water hammer that has taken place (Fig. 4);

Rice. 4. Characteristic damage to the pressure gauge by water hammer

- each water hammer in an apartment pipeline made of polymeric materials, made on crimp, press or sliding connectors, inevitably leads to a microscopic "slipping" of the connector from the pipeline. In the end, there may come a moment when the next water hammer becomes critical - the pipe will completely “creep out” of the connector (Fig. 5);

Rice. 5. Violation of the crimp connection MPT as a result of the impact of water hammer

- cavitation phenomena that can accompany hydraulic shock are often the cause of cavities in the spool and valve body. The collapse of vacuum bubbles during cavitation simply “gnaws out” pieces of metal from the surface on which they form. As a result, the spool ceases to fulfill its function, that is, the tightness of the shut-off organ is broken. Yes, and the body of such fittings will fail very quickly (Fig. 6);

Rice. 6. Cavitation destruction of the inner surface of the surge in front of the solenoid valve

- a special danger for apartment pipelines made of multilayer pipes is the zone of shock wave discharge during hydraulic shock. If the adhesive layer is of poor quality or there are non-glued areas, the vacuum formed in the pipe tears off the inner layer of the pipe, causing it to “collapse” (Fig. 7, 8).

Rice. 7. Multilayer polypropylene pipe affected by water hammer

Rice. 8. "Collapsed" metal-polymer pipe

With partial collapse, the pipe will continue to perform its function, but with much greater hydraulic resistance. However, a complete collapse can also occur - in this case, the pipe will be blocked by its own inner layer. Unfortunately, GOST 53630-2009 "Multilayer pressure pipes" does not require testing of pipe samples at an internal pressure below atmospheric. However, a number of manufacturers, knowing about such a problem, include in the technical specifications a mandatory clause on checking the pipe under vacuum. In particular, each roll of VALTEC multilayer pipes is connected to a vacuum pump, which brings the absolute pressure in the pipe to 0.2 atm (-0.8 barg). Then, with the help of a compressor, a polystyrene foam ball with a diameter slightly smaller than the design inner diameter of the pipe is driven through the pipe. Rolls through which the ball could not pass are mercilessly rejected and destroyed;

- Another danger lurks in case of water hammer internal pipelines of hot water supply. As you know, the boiling point of water is closely related to pressure ( tab. 5).

Table 5. Dependence of the boiling point of water on pressure


If, for example, an apartment pipeline enters hot water with a temperature of 70 ° C, and in the zone of rarefaction of the water hammer, the pressure decreases to an absolute value of 0.3 atm, then in this zone the water will turn into steam. Taking into account that the volume of steam under normal conditions is almost 1200 times greater than the volume of the same mass of water, it should be expected that this phenomenon can lead to an even greater increase in pressure in the shock wave compression zone.

Methods of protection against water hammer in apartment systems

The most effective and reliable way to protect against water hammer is to increase the time for shutting off the flow with a shut-off device. This method is used on main pipelines. The smooth closing of the valve does not cause any destructive disturbances in the flow and eliminates the need to install bulky and expensive damping devices. In apartment systems, this method is not always acceptable, because. “one-handed” lever mixers, solenoid valves for household appliances, and other fittings capable of shutting off the flow in a short period of time have firmly entered our everyday life. In this regard, apartment engineering systems already at the design stage must necessarily be designed taking into account the risk of water hammer. Structural measures, such as the use of elastic inserts, compensation loops and expanders, are not widely used. At present, the most popular fittings specially designed for this purpose are pneumatic (piston, Fig. 9a, and membrane, Fig. 9b) or spring (Fig. 9c) hydraulic shock absorbers.

Rice. 9. Types of hydraulic shock absorbers

In a pneumatic damper, the kinetic energy of the fluid flow is damped by the energy of air compression, the pressure of which varies along the adiabatic with the exponent K = 1.4. The volume of the air chamber of the pneumatic damper is determined from the expression:

where P 0 is the initial pressure in the air chamber, P K is the final (limiting) pressure in the air chamber. In the above formula, the left side is an expression for the kinetic energy of the fluid flow, and the right side is the expression for the air compression energy.

Spring parameters for spring compensators are found from the expression:

where D pr is the average diameter of the spring, I is the number of turns of the spring, G is the shear modulus, F to is the final force acting on the spring, F 0 is the initial force acting on the spring.

There is an opinion among designers and installers that check valves and pressure reducers also have the ability to absorb water hammer.

Check valves, indeed, by cutting off part of the pipeline at the moment of a sharp shutdown of the flow, reduce the estimated length of the pipeline, turning a direct blow into an indirect, less energy. However, closing abruptly under the influence of the shock wave compression stage, the valve itself becomes the cause of water hammer in the pipeline located before it. In the discharge stage, the valve opens again, and, depending on the ratio of the lengths of the pipes before the valve and after it, a moment may come when the shock waves of the two sections will add up, increasing the pressure jump. Piston pressure reducers cannot serve as hydraulic shock absorbers due to their high inertia - due to the work of friction forces in the piston seals, they simply do not have time to respond to an instantaneous pressure change. In addition, such gearboxes themselves need protection against water hammer, which causes the sealing rings to be squeezed out of the piston seats.

Membrane pressure reducers have the ability to partially absorb the energy of water hammers, but they are designed for completely different force effects, so the work to dampen frequent water hammers will quickly disable them. In addition, a sharp overlap of the gearbox during a shock wave leads, as in the case of check valve, to the occurrence of a shock wave in the area up to the gearbox, which is not protected by a membrane.

Among other things, apartment water hammer dampers, in addition to fulfilling their main task, perform several more functions that are important for the safe operation of apartment pipelines. These functions will be considered using the VALTEC VT.CAR19 membrane hydraulic shock absorber as an example (Fig. 10).

Water hammer absorber VT.CAR19

Rice. 10. Water hammer damper VALTEC VT.CAR19

The residential hydraulic shock absorber VALTEC VT.CAR19 structurally consists (Fig. 11) of a spherical body made of AISI 304L stainless steel ( 1 ), with rolled EPDM membrane ( 2 ). Due to small bulges on the surface of the membrane, its loose connection to the body and the maximum contact area of ​​the membrane with the transported medium are ensured. The damper's air chamber is at a factory pressure of 3.5 bar, which ensures the protection of apartment pipelines, the pressure in which does not exceed 3 bar. The extinguisher can also protect pipelines with a working pressure of up to 10 bar, but in this case it is necessary with a pump connected to the nipple ( 3 ) increase the pressure in the air chamber to 10.5 bar. In the case when the operating pressure in the apartment network is lower than 3 bar, it is recommended through the nipple ( 3 ) let some of the air out of the chamber up to Pwork + 0.5 bar.

Fig.11. Construction of the absorber VALTEC VT.CAR19

Specifications and overall dimensions of the absorber are given in tab. 6.

Table 6. Specifications of VALTEC VT.CAR19


Characteristic name

Meaning

Working volume

Air chamber pre-pressure factory setting

Maximum pressure during water hammer

Maximum operating pressure in the protected apartment pipeline

Medium temperature range


Dimensions (see sketch):



H - height

O - diameter

G - connecting thread

Material:



Stainless steel AISI 304L

Membrane

The damper is able to protect pipelines from water hammer, the pressure at which increases up to 20 bar, therefore, before installing the damper, it is necessary to check how much water hammer can occur in a particular apartment pipeline. Calculation of the possible pressure during water hammer Pg can be calculated by the formula:

, bar.

The ratio Ewater/Est for pipelines made of different materials is taken according to tab. 2.

Reliably protecting apartment pipelines from water hammer, the VT.CAR19 absorber, due to its design features, is able to absorb excess water formed when the incoming cold water is heated during a break in water use. For example, if water with a temperature of +5 ° C enters an apartment equipped with a reducer or a check valve at the inlet, and it warms up to 25 ° C overnight (the usual air temperature in the bathroom), then the pressure in the cut-off section of the pipeline will increase by:

∆P = β t Δt/β v \u003d 0.00015 (25 - 5) / 4.9 10 -9 \u003d 61.2 bar.

In the above formula βt is the coefficient of thermal expansion of water, and β v is the coefficient of volumetric compression of water (the reciprocal of the modulus of elasticity). The formula does not take into account the thermal expansion of the material of the pipe itself, but practice shows that each degree increase in the temperature of the water in the pipeline increases the pressure from 2 to 2.5 bar.

This is where the second function of the membrane hydraulic shock absorber is required. Having taken in some of the water from the heating pipeline, it will save it from excessive load and help to avoid an emergency. IN tab. 7 the maximum lengths of pipelines protected by the damper VT.CAR19 from thermal expansion of the liquid are given.

Table 7. Maximum length of pipelines protected from thermal expansion (at ΔТ = 20°C)


As for residential hot water pipelines, here too the VT.CAR19 absorber performs an important task of preventing water from boiling in the zone of shock wave discharge. By absorbing the energy of the water hammer, the absorber eliminates this danger as well.

The greatest efficiency of the hydraulic shock absorber is achieved when it is installed directly in front of the protected reinforcement. In this case, the possibility of a water hammer is completely excluded (Fig. 12).

Rice. 12. Installation of absorbers directly in front of protected devices

In apartment systems, where pipelines do not have a significant length, it is allowed to install one damper per group of devices. In this case, it should be checked that the total length of pipeline sections protected by one extinguisher does not exceed the values ​​set forth in tab. 8.

Table 8. Length of pipeline sections protected by one extinguisher


If the values ​​specified in the table are exceeded, it is necessary to install not one, but several absorbers. In the event that the calculated water hammer pressure exceeds the maximum allowable pressure for a given absorber (20 bar for VT.CAR19), another type of device with higher strength characteristics should be selected.

In accordance with clause 7.1.4. SP 30.13330.2012 "Internal water supply and sewerage of buildings", the provisions of which came into force on January 1, 2013, the design of water folding and shutoff valves should ensure smooth opening and closing of the water flow. But this requirement is unlikely to be met, because trade offers residents a huge range of fittings and appliances in which smooth regulation is impossible. Taking this into account, the leading design and construction organizations of our country already now provide for the installation of residential hydraulic shock absorbers in their projects. For example, DSK-1 of the city of Moscow restructures production to perform apartment water supply input nodes according to the scheme shown in fig. 13.

Rice. 13. Knot apartment water supply

IN Lately Increasingly, there are reports of the destruction of some elements of the heating or plumbing system. The cause of the failure is water hammer. The compensator (quencher) of water hammer saves from such troubles. What kind of device is this, how and where to install it - read in this article.

What is a water hammer in a pipeline, causes

water hammer- this is a sharp increase in pressure in systems transporting liquid, which occurs when a sharp change in the speed of the liquid. A pressure surge can cause the destruction of some elements of the system. Destruction occurs if the tensile strength of the connection or material is exceeded.

If we talk about our houses and apartments, water hammer occurs in heating and water supply systems. In heating systems of private houses - when starting or stopping the circulation pump. Yes, by itself it does not create pressure. But a sharp acceleration or stop of the coolant is the load that acts on the walls of the pipes and nearby devices. In closed-type heating systems it costs. It compensates for water hammer if the pump is nearby. In this case, additional devices may not be needed. You can check the need to install a compensator using a pressure gauge. If the arrow does not move, or moves only slightly, everything is fine.

The most common cause of water hammer is a sudden shutdown of a tap.

In centralized heating systems, water hammer occurs when the damper closes abruptly, when taps are quickly opened to fill the system after repair / maintenance. According to the rules, this should be done slowly and gradually, but in practice it happens otherwise ...

In water supply, water hammer occurs even when a tap or other shut-off valve is abruptly closed. More pronounced "effects" are obtained in air-to-air systems. When moving, water hits air pockets, which creates additional shock loads. We may hear clicks or crackles. And if the water supply is diluted with plastic pipes, during operation you can notice how these pipes shake. This is how they react to water hammer. You have probably noticed how the hose in the metal braid twitches. The reason is the same - pressure surges. Sooner or later they will lead to the fact that either the pipe will burst in the weak spot, or the connection will leak (which is more likely and more common).

Why hasn't this been seen before? Because now most of the valves have a ball valve and the flow is blocked / opened very abruptly. Previously, the taps were of the valve type and the damper was lowered slowly and gradually.

How to deal with water hammer in heating and water supply? You can, of course, teach the inhabitants of an apartment or house not to turn the taps sharply. But you can't teach a washing machine or a dishwasher careful attitude to the pipes. And the circulation pump will not slow down in the process of starting and stopping. Therefore, water hammer compensators are added to the heating or water supply system. They are also called absorbers, shock absorbers.

What is a water hammer compensator: types, design, principle of operation

There are two types of water hammer compensator: membrane and spring-loaded valve. They perform the same function: they accept excess fluid, thereby reducing the load on other elements of the system. Since these devices are small, they protect those devices that are located in close proximity.

The water hammer compensator is a small device, but it changes the picture significantly

How a membrane compensator is arranged and works

A membrane water hammer compensator is a container that is divided into two parts by an elastic membrane. One of the parts is filled with air, the other is empty in the normal state. The air in the filled part is pumped under a certain pressure. To check / pump pressure in this part of the body there is a spool (nipple). From the factory, the products are delivered with an initial pressure of 3 bar. This is the "standard" value for most heating systems of one-story private houses. If the pressure needs to be changed, a pump is connected to the nipple and brought to the required value. This value is 20-30% higher than the working one in a particular system. But it should be significantly lower than the operating limit of the compensator itself.

As long as the pressure in the system does not exceed the pressure in that part of the tank, nothing happens. When a water hammer occurs, under the action of increased pressure, the membrane is stretched, part of the liquid enters the tank. As it normalizes, the elastic membrane tends to return to its normal state, pushing fluid back into the system. Thus, the jump is smoothed out.

Features of the spring water hammer damper

The second type of water hammer compensator works on the same principle: liquid is passed into the body when the pressure rises. But access to the container is blocked by a plastic disk, which is supported by a spring. The pressure at which the liquid begins to flow in depends on the elastic force of the spring. You can’t regulate it in any way (at least until adjustable models come across), so you have to select a device with suitable parameters.

The principle of operation of this absorber is similar to that described above. While the pressure in the system is normal, the spring presses the disc against the housing. When a water hammer occurs, it contracts, water enters the body. As the pressure decreases, it becomes less than the elastic force of the spring. It gradually expands, returning the liquid to the pipeline.

As you can see, both devices work on a similar principle. Spring models are considered to be more reliable, since the working elements in them are less subject to wear (metal spring and durable plastic). But membranes are also made from materials that long time do not lose their elasticity. An additional plus is the ability to set the pressure at which the membrane begins to stretch. But the disadvantage can be considered the need for regular pressure checks and, if necessary, pumping.

The water hammer compensator is small, only a small amount of water can fit in the housing (less than 200 ml usually). It is installed in the immediate vicinity in front of the source of the occurrence of water hammer: a ball valve, a water comb, on a hose to a washing machine or dishwasher, after a circulation pump, on a heated floor comb.

You can mount it in any position: up, down, to the side. For membrane models, it is only important that there is free access to the nipple. Regardless of the design, it is not recommended to install the device on long branches from the main. The supply pipe must be as short as possible.

When choosing, pay attention to the maximum working and compensated pressure. The second point is the diameter of the connection. Usually it is 1/2 inch, but there are also 3/4 and inch.

When connecting a washing machine and / or dishwasher, a tee is installed on the hose. One free outlet of the tee goes to the machine, a water hammer compensator is installed on the second.

Other ways to deal with water hammer

One of options neutralization of the water hammer has already been voiced - close the taps smoothly. But this is not a panacea, and it is inconvenient in our fast-paced time. And there is also household appliances, you can’t teach them. Although, some manufacturers take this moment into account, and the latest models are made with a valve that smoothly shuts off the water. That's why compensators and neutralizers are becoming so popular.

Water hammer compensator - a small device (comparison with a brass ball valve)

You can deal with water hammer in other ways:

  • When distributing or reconstructing a water supply or heating system, insert a piece of an elastic pipe in front of the source of water hammer. It is reinforced heat resistant rubber or PPS plastic. The length of the elastic insert is 20-40 cm. The longer the pipe, the longer the insert.
  • Purchase of household appliances and shut-off and control valves with a smooth valve stroke. If we talk about heating, there are often problems with. Not all servomotors run smoothly when the flow is closed. The way out is to install thermostats / thermostats with a smooth piston stroke.
  • Use pumps with soft start and stop.

Water hammer is a really dangerous thing for a closed system. He breaks radiators, breaks pipes. To avoid problems, it is better to think over control measures in advance. If everything is already working, but there are problems, it is wiser and easiest to install compensators. Yes, they are not cheap, but repairs will cost more.

Manufacturers, characteristics, prices

It is best to buy a water hammer compensator from well-known companies. This is not the area where it is appropriate to save. The most popular are several companies:


There are other companies, but they are not so popular. some due to overpricing, others have not gained credibility. Anyway, for now.

General information about water hammer

Water hammer is an abrupt change in the pressure of a fluid flowing in a pressure pipeline that occurs when a sudden change in flow velocity occurs. In a broader sense, water hammer is a rapid alternation of “jumps” and “dips” in pressure, accompanied by deformation of the fluid and pipe walls, as well as an acoustic effect similar to a hammer hitting a steel pipe. With weak hydraulic shocks, the sound manifests itself in the form of “metallic” clicks, however, even with such seemingly insignificant shocks, the pressure in the pipeline can increase quite significantly.

The stages of water hammer can be illustrated by the following example ( fig.1): let a single-lever tap or mixer be installed at the end of the apartment pipeline connected to the house riser (it is these mixers that allow you to shut off the flow relatively quickly).

Fig.1. Water hammer stages

When the valve is closed, the following processes occur:

  1. While the tap is open, the liquid moves through the apartment pipeline at a speed of " ν ". At the same time, the pressure in the riser and the apartment pipeline is the same ( p).
  2. When the valve is closed and the flow is abruptly decelerated, the kinetic energy of the flow is converted into the work of deformation of the pipe walls and the liquid. The walls of the pipe are stretched, and the liquid is compressed, which leads to an increase in pressure by an amount ∆p(shock pressure). The zone in which the pressure increase has occurred is called the shock wave compression zone, and its extreme section is called the shock wave front. The front of the shock wave propagates towards the riser at a speed of "c". Here I would like to note that the assumption of the incompressibility of water, adopted in hydraulic calculations, is not applied in this case, because real water is a compressible liquid with a volumetric compression ratio of 4.9x10 -10 1/Pa. That is, at a pressure of 20,400 bar (2040 MPa), the volume of water is halved.
  3. When the front of the shock wave reaches the riser, all the liquid in the apartment pipeline will be compressed, and the walls of the apartment pipeline will be stretched.
  4. The volume of liquid in the house system is much larger than in the apartment wiring, therefore, when the shock wave front reaches the riser, the excess fluid pressure is mostly smoothed out by expanding the cross section and turning on the total volume of liquid in the house system. The pressure in the apartment pipeline begins to equalize with the riser pressure. But at the same time, the apartment pipeline, due to the elasticity of the wall material, restores its original cross section, compressing the liquid and squeezing it into the riser. The zone of removal of deformation from the walls of the pipeline extends to the valve with a speed of " With».
  5. At the moment when the pressure in the apartment pipeline is equal to the original one, as well as the fluid velocity, the flow direction will be reversed ("zero point").
  6. Now the liquid in the pipeline with a speed of " ν ” tends to “break away” from the crane. There is a "shock wave rarefaction zone". In this zone, the flow velocity is zero, and the fluid pressure becomes lower than the initial one, which leads to compression of the pipe walls (diameter reduction). The rarefaction zone front moves to the riser at a speed of " With". With a significant initial flow rate, the vacuum in the pipe can lead to a decrease in pressure below atmospheric, as well as to a violation of the continuity of the flow (cavitation). In this case, a cavitation bubble appears in the pipeline near the valve, the collapse of which leads to the fact that the fluid pressure in the zone of the reflected shock wave becomes greater than the same indicator in the direct shock wave.
  7. When the compression front of the shock wave of the riser is reached, the flow velocity in the apartment pipeline is zero, and the liquid pressure is lower than the initial one and lower than the pressure in the riser. The walls of the pipeline are compressed.
  8. The pressure difference between the liquid in the riser and the apartment pipeline causes the liquid to enter the apartment pipeline and equalize the pressures to the original value. In this regard, the walls of the pipe also begin to acquire their original shape. Thus, a reflected shock wave is formed, and the cycles are repeated again until complete extinction. In this case, the time interval during which all stages and cycles of hydraulic shock pass does not exceed, as a rule, 0.001–0.06 s. The number of cycles can be different and depends on the characteristics of the system.

On rice. 2 the stages of water hammer are shown graphically.

Rice. 2. Graphs of pressure change during hydraulic shock.

Schedule on rice. 2a shows the development of hydraulic shock when the pressure of the liquid in the shock wave discharge zone does not fall below atmospheric pressure (line 0).

Schedule on rice. 2b displays a shock wave, the rarefaction zone of which is below atmospheric pressure, but the hydraulic continuity of the medium is not violated. In this case, the liquid pressure in the rarefaction zone is lower than atmospheric pressure, but no cavitation effect is observed.

Schedule on fig.2c displays the case when the hydraulic continuity of the flow is violated, that is, a cavitation zone is formed, the subsequent collapse of which leads to an increase in pressure in the reflected shock wave.

Varieties of hydraulic shocks and basic design provisions

Depending on the speed with which the shut-off device on the pipeline is closed, water hammer can be "direct" and indirect. "Direct" is called a shock, in which the flow overlap occurs in a time less than the shock period, that is, the condition is met:

T 3 ≤ 2L/c,

Where T 3 is the closing time of the locking organ, s; L- the length of the pipeline from the locking device to the point at which constant pressure is maintained (in the apartment - to the riser), m; With is the shock wave velocity, m/s.

Otherwise, the water hammer is called indirect. With an indirect impact, the pressure jump is much smaller in magnitude, since part of the flow energy is damped by partial leakage through the shut-off device.

Depending on the degree of flow blocking, the water hammer can be complete or incomplete. A complete blow is one in which the shut-off element completely blocks the flow. If this does not happen, that is, part of the flow continues to flow through the shut-off organ, then the water hammer will be incomplete. In this case, the difference in flow rates before and after shutoff will be the calculated velocity for determining the magnitude of water hammer. The magnitude of the pressure increase during direct full hydraulic shock can be determined by the formula of N.E. Zhukovsky (in Western technical literature, the formula is attributed to Alievi and Michaud):

Δp = ρ ν s, Pa,

Where ρ – density of the transported liquid, kg/m 3 ; ν is the speed of the transported fluid until the moment of sudden braking, m/s; With is the velocity of shock wave propagation, m/s.

In turn, the shock wave propagation velocity c is determined by the formula:

Where c 0- the speed of sound propagation in a liquid (for water - 1425 m / s, for other liquids can be taken according to tab. 1); D– pipeline diameter, m; δ – pipe wall thickness, m; E f is the bulk modulus of elasticity of the liquid (can be taken according to tab. 2), Pa; Eating is the modulus of elasticity of the pipe wall material, Pa (can be taken according to tab. 3).

Table 1. Characteristics of liquids

Table 2. Characteristics of pipe wall materials

If we take into account that the speed of water movement in apartment systems should not exceed 3 m / s (clause 7.6. SNiP 2.04.01), then for pipelines made of various materials, it is possible to calculate the magnitude of the pressure increase with a possible direct full hydraulic shock. Such summary data for some pipes are presented in tab. 3.

Table 3. Pressure increase during water hammer at a flow velocity of 3 m/s

Pipe material and dimensions

Shock wave speed, m/s

Δp, bar

Metal polymer

Polyethylene

Polypropylene

Steel (VGP normal pipes)

With indirect water hammer, the pressure increase is calculated by the formula:

IN tab. 4 the average response time of the main apartment fittings is given. For each type of this fitting, the length of the pipeline is calculated, more than which the water hammer ceases to be direct.

Table 4. The length of the direct impact section for water shut-off valves

Possible consequences of hydraulic shocks

In apartment networks, the occurrence of water hammer, of course, does not entail such large-scale destructive consequences as on large-diameter main pipelines. However, even here they can cause a lot of trouble and loss, if you do not take into account the possibility of their occurrence.

Periodically recurring hydraulic shocks in apartment piping can cause the following troubles:

– reduction of service life of pipelines. The normative service life of internal pipelines is determined by the totality of characteristics (temperature, pressure, time) in which the pipe is operated. Even such short-term, but often recurring, alternating pressure surges and dips that occur during hydraulic shock significantly distort the picture of the operational mode of the pipeline, reducing its trouble-free operation. To a greater extent, this applies to polymer and multilayer pipelines;

- extrusion of gaskets and seals in fittings and pipeline connectors. Elements such as piston pressure reducers, ball valves, valves and mixers with rubber gland rings, o-rings for compression and press connectors, as well as rings for half-strings (“American women”) are subject to this. In apartment water meters, extrusion of the sealing ring between the measuring chamber and the counting mechanism can lead to water entering the counting mechanism (Fig. 3);

Rice. 3. Water ingress into the counting mechanism of the water meter as a result of gasket extrusion

- even a single water hammer can completely disable the instrumentation installed in the apartment. For example, the bending of the pressure gauge needle from interaction with the restrictive pin is a clear sign of a water hammer that has taken place (Fig. 4);

Rice. 4. Characteristic damage to the pressure gauge by water hammer

- each water hammer in an apartment pipeline made of polymeric materials, made on crimp, press or sliding connectors, inevitably leads to a microscopic "slipping" of the connector from the pipeline. In the end, there may come a moment when the next water hammer becomes critical - the pipe will completely “creep out” of the connector (Fig. 5);

Rice. 5. Violation of the crimp connection MPT as a result of the impact of water hammer

- cavitation phenomena that can accompany hydraulic shock are often the cause of cavities in the spool and valve body. The collapse of vacuum bubbles during cavitation simply “gnaws out” pieces of metal from the surface on which they form. As a result, the spool ceases to fulfill its function, that is, the tightness of the shut-off organ is broken. Yes, and the body of such fittings will fail very quickly (Fig. 6);

Rice. 6. Cavitation destruction of the inner surface of the surge in front of the solenoid valve

- a special danger for apartment pipelines made of multilayer pipes is the zone of shock wave discharge during hydraulic shock. If the adhesive layer is of poor quality or there are non-glued areas, the vacuum formed in the pipe tears off the inner layer of the pipe, causing it to “collapse” (Fig. 7, 8).

Rice. 7. Multilayer polypropylene pipe affected by water hammer

Rice. 8. "Collapsed" metal-polymer pipe

With partial collapse, the pipe will continue to perform its function, but with much greater hydraulic resistance. However, a complete collapse can also occur - in this case, the pipe will be blocked by its own inner layer. Unfortunately, GOST 53630-2009 "Multilayer pressure pipes" does not require testing of pipe samples at an internal pressure below atmospheric. However, a number of manufacturers, knowing about such a problem, include in the technical specifications a mandatory clause on checking the pipe under vacuum. In particular, each roll of VALTEC multilayer pipes is connected to a vacuum pump, which brings the absolute pressure in the pipe to 0.2 atm (-0.8 barg). Then, with the help of a compressor, a polystyrene foam ball with a diameter slightly smaller than the design inner diameter of the pipe is driven through the pipe. Rolls through which the ball could not pass are mercilessly rejected and destroyed;

- Another danger lurks in case of water hammer internal pipelines of hot water supply. As you know, the boiling point of water is closely related to pressure ( tab. 5).

Table 5. Dependence of the boiling point of water on pressure

If, for example, hot water with a temperature of 70 ° C enters the apartment pipeline, and in the zone of rarefaction of the water hammer the pressure drops to an absolute value of 0.3 atm, then in this zone the water will turn into steam. Taking into account that the volume of steam under normal conditions is almost 1200 times greater than the volume of the same mass of water, it should be expected that this phenomenon can lead to an even greater increase in pressure in the shock wave compression zone.

Methods of protection against water hammer in apartment systems

The most effective and reliable way to protect against water hammer is to increase the time for shutting off the flow with a shut-off device. This method is used on main pipelines. The smooth closing of the valve does not cause any destructive disturbances in the flow and eliminates the need to install bulky and expensive damping devices. In apartment systems, this method is not always acceptable, because. “one-handed” lever mixers, solenoid valves for household appliances, and other fittings capable of shutting off the flow in a short period of time have firmly entered our everyday life. In this regard, apartment engineering systems already at the design stage must necessarily be designed taking into account the risk of water hammer. Structural measures, such as the use of elastic inserts, compensation loops and expanders, are not widely used. At present, the most popular fittings specially designed for this purpose are pneumatic (piston, Fig. 9a, and membrane, Fig. 9b) or spring (Fig. 9c) hydraulic shock absorbers.

Rice. 9. Types of hydraulic shock absorbers

In a pneumatic damper, the kinetic energy of the fluid flow is damped by the energy of air compression, the pressure of which varies along the adiabatic with the exponent K = 1.4. The volume of the air chamber of the pneumatic damper is determined from the expression:

where P 0 is the initial pressure in the air chamber, P K is the final (limiting) pressure in the air chamber. In the above formula, the left side is an expression for the kinetic energy of the fluid flow, and the right side is the expression for the air compression energy.

Spring parameters for spring compensators are found from the expression:

where D pr is the average diameter of the spring, I is the number of turns of the spring, G is the shear modulus, F to is the final force acting on the spring, F 0 is the initial force acting on the spring.

There is an opinion among designers and installers that check valves and pressure reducers also have the ability to absorb water hammer.

Check valves, indeed, by cutting off part of the pipeline at the moment of a sharp shutdown of the flow, reduce the estimated length of the pipeline, turning a direct blow into an indirect, less energy. However, closing abruptly under the influence of the shock wave compression stage, the valve itself becomes the cause of water hammer in the pipeline located before it. In the discharge stage, the valve opens again, and, depending on the ratio of the lengths of the pipes before the valve and after it, a moment may come when the shock waves of the two sections will add up, increasing the pressure jump. Piston pressure reducers cannot serve as hydraulic shock absorbers due to their high inertia - due to the work of friction forces in the piston seals, they simply do not have time to respond to an instantaneous pressure change. In addition, such gearboxes themselves need protection against water hammer, which causes the sealing rings to be squeezed out of the piston seats.

Membrane pressure reducers have the ability to partially absorb the energy of water hammers, but they are designed for completely different force effects, so the work to dampen frequent water hammers will quickly disable them. In addition, a sharp closing of the gearbox during a shock wave leads, as in the case of a non-return valve, to the occurrence of a shock wave in the area up to the gearbox, which is not protected by a membrane.

Among other things, apartment water hammer dampers, in addition to fulfilling their main task, perform several more functions that are important for the safe operation of apartment pipelines. These functions will be considered using the VALTEC VT.CAR19 membrane hydraulic shock absorber as an example (Fig. 10).

Water hammer absorber VT.CAR19

Rice. 10. Water hammer damper VALTEC VT.CAR19

The residential hydraulic shock absorber VALTEC VT.CAR19 structurally consists (Fig. 11) of a spherical body made of AISI 304L stainless steel ( 1 ), with rolled EPDM membrane ( 2 ). Due to small bulges on the surface of the membrane, its loose connection to the body and the maximum contact area of ​​the membrane with the transported medium are ensured. The damper's air chamber is at a factory pressure of 3.5 bar, which ensures the protection of apartment pipelines, the pressure in which does not exceed 3 bar. The extinguisher can also protect pipelines with a working pressure of up to 10 bar, but in this case it is necessary with a pump connected to the nipple ( 3 ) increase the pressure in the air chamber to 10.5 bar. In the case when the operating pressure in the apartment network is lower than 3 bar, it is recommended through the nipple ( 3 ) let some of the air out of the chamber up to Pwork + 0.5 bar.

Fig.11. Construction of the absorber VALTEC VT.CAR19

The technical characteristics and overall dimensions of the absorber are given in tab. 6.

Table 6. Specifications of VALTEC VT.CAR19

Characteristic name

Meaning

Working volume

Air chamber pre-pressure factory setting

Maximum pressure during water hammer

Maximum operating pressure in the protected apartment pipeline

Medium temperature range

Dimensions (see sketch):

H - height

O - diameter

G - connecting thread

Material:

Stainless steel AISI 304L

Membrane

The damper is able to protect pipelines from water hammer, the pressure at which increases up to 20 bar, therefore, before installing the damper, it is necessary to check how much water hammer can occur in a particular apartment pipeline. The calculation of the possible pressure during water hammer Р gu can be calculated by the formula:

, bar.

The ratio Ewater/Est for pipelines made of different materials is taken according to tab. 2.

Reliably protecting apartment pipelines from water hammer, the VT.CAR19 absorber, due to its design features, is able to absorb excess water formed when the incoming cold water is heated during a break in water use. For example, if water with a temperature of +5 ° C enters an apartment equipped with a reducer or a check valve at the inlet, and it warms up to 25 ° C overnight (the usual air temperature in the bathroom), then the pressure in the cut-off section of the pipeline will increase by:

∆P = β t Δt/β v \u003d 0.00015 (25 - 5) / 4.9 10 -9 \u003d 61.2 bar.

In the above formula βt is the coefficient of thermal expansion of water, and β v is the coefficient of volumetric compression of water (the reciprocal of the modulus of elasticity). The formula does not take into account the thermal expansion of the material of the pipe itself, but practice shows that each degree increase in the temperature of the water in the pipeline increases the pressure from 2 to 2.5 bar.

This is where the second function of the membrane hydraulic shock absorber is required. Having taken in some of the water from the heating pipeline, it will save it from excessive load and help to avoid an emergency. IN tab. 7 the maximum lengths of pipelines protected by the damper VT.CAR19 from thermal expansion of the liquid are given.

Table 7. Maximum length of pipelines protected from thermal expansion (at ΔТ = 20°C)

As for residential hot water pipelines, here too the VT.CAR19 absorber performs an important task of preventing water from boiling in the zone of shock wave discharge. By absorbing the energy of the water hammer, the absorber eliminates this danger as well.

The greatest efficiency of the hydraulic shock absorber is achieved when it is installed directly in front of the protected reinforcement. In this case, the possibility of a water hammer is completely excluded (Fig. 12).

Rice. 12. Installation of absorbers directly in front of protected devices

In apartment systems, where pipelines do not have a significant length, it is allowed to install one damper per group of devices. In this case, it should be checked that the total length of pipeline sections protected by one extinguisher does not exceed the values ​​set forth in tab. 8.

Table 8. Length of pipeline sections protected by one extinguisher

If the values ​​specified in the table are exceeded, it is necessary to install not one, but several absorbers. In the event that the calculated water hammer pressure exceeds the maximum allowable pressure for a given absorber (20 bar for VT.CAR19), another type of device with higher strength characteristics should be selected.

In accordance with clause 7.1.4. SP 30.13330.2012 "Internal water supply and sewerage of buildings", the provisions of which came into force on January 1, 2013, the design of water folding and shutoff valves should ensure smooth opening and closing of the water flow. But this requirement is unlikely to be met, because trade offers residents a huge range of fittings and appliances in which smooth regulation is impossible. Taking this into account, the leading design and construction organizations of our country already now provide for the installation of residential hydraulic shock absorbers in their projects. For example, DSK-1 of the city of Moscow restructures production to perform apartment water supply input nodes according to the scheme shown in fig. 13.

Rice. 13. Apartment water supply unit DSK-1

Water hammer is a sudden increase in pressure in a pipeline caused by a rapid change in the flow rate of water. Positive water hammer occurs due to abrupt closing of the valve, and negative water hammer occurs due to abrupt opening. Positive water hammer is very undesirable for heating and water supply systems.

The consequences can be - cracks in the pipes, failure of the pump, heat exchanger, water meter, pressure gauge and other pressure equipment, and of course the cessation of water and heat supply to the house, flooding of the neighbors in the apartment from the lower floors. Worst of all is the rupture of the pipeline. Constant exposure to shock can lead to depressurization of even a new water supply.

Causes of water hammer

  • Abrupt closing/opening of valves
  • The presence of air in the pipes (it is necessary to bleed air from the system)
  • Interruptions in operation or failure of the pump
  • System installation errors

In a modern system, instead of threaded valves, which provide for a smooth shutoff of the water flow, more often they use Ball Valves, which sharply overlap the system. They are convenient and reliable in use, but the number of water hammers increases with their use in the system.

If the water supply system is not properly installed, then water hammer can also occur using valves. The main reason - sharp transitions in pipe diameter. When a liquid moves under pressure through a large diameter pipe and reaches the place where the pipe "narrows" - this can also cause problems, since any obstacle in the path of a liquid moving at a speed changes its volume and, accordingly, pressure. This also applies to sharp turns and pipeline bends. Pipelines with a pipe diameter of up to 100 mm and wiring over long distances are the least protected from such an impact.

Water hammer also occurs due to the formation of air voids, especially at a pipe bend.

The figure below clearly shows what happens to the pipe when the tap is abruptly closed - water hammer:

Ways to prevent water hammer

You can protect the water supply system of a house or apartment in different ways:

  • First, you need to inspect the entire system for leaks and general suitability for use, the degree of pipe wear. Old pipes should be replaced with new ones. The reliability of the system depends on the quality of materials and proper installation.
  • Installation of valves of valve type. Gently close the tap so that the pressure in the water supply system equalizes smoothly.
  • Using larger pipes . Choose a pipe diameter greater than 100 mm. The larger the diameter of the pipes, the lower the water flow rate and, accordingly, the water hammer.
  • Avoid long pipe runs and no sharp bends to prevent air pockets.
  • Avoid sudden temperature changes in the water pipe. When designing a house, it must be taken into account that the pipes go to those places and rooms where the temperature difference will be minimal. Make pipe insulation.
  • Always take preventive measures:
  1. Check the operation of the safety group: pressure gauge, air vent, safety valve.
  2. Regularly check the condition of the filters that trap sand and rust.
  • Use compensatory equipment.

Compensators and water hammer dampers- special devices that are able to take in a part of the liquid from the general system when the pressure increases, reducing it in this way.

If your home is supplied with water from an autonomous source using pumping equipment, then use hydraulic accumulator. It is part of pumping stations and is a tank with a rubber membrane, where, during a water hammer, excess water will be discharged until the system pressure is normalized. A pressure switch is an element that will not save you from water hammer, but will turn off the pump when you turn off the tap and the pressure exceeds a certain value. In this case, it must be borne in mind that the pump will not turn off instantly. Use a pump with a frequency converter that automatically regulates its operation and ensures smooth starting and stopping. A sharp increase in pressure in the system, which leads to water hammer, is excluded.

As a shock absorber, you can use a pipe made of elastic plastic or heat-resistant reinforced rubber, which will dampen the energy of water hammer.

The most vulnerable to hydraulic shocks are long pipelines, for example, underfloor heating. To secure such a system, it is equipped with a thermostatic valve.

Thermostat with super protection. Sometimes a thermostat with special protection against water hammer is used. Such devices have a spring mechanism installed between the valve and the thermal head. With excess pressure, the spring is activated and does not allow the valve to close completely, as soon as the power of the water hammer decreases, the valve closes smoothly. Install such a thermostat strictly in the direction of the arrow on the housing.

Scheme of the hydraulic shock compensator device

The diagrams above show examples of how to properly install expansion joints. They can be mounted horizontally or vertically, on cold and hot water collectors or on any section of the pipeline leading to the end point of water consumption.

Here it is necessary to pay attention to the fact that water stagnation at the entrance to the compensator must not be allowed, otherwise bacteria may begin to multiply in the system. Therefore, the instruction does not allow its installation at the top of the riser.

According to statistics, more than half of pipeline accidents are not due to corrosion or material fatigue. Their cause is water hammer in the water supply system. But they can be completely avoided if you immediately mount the system in accordance with all the rules, and equip it with special devices that dampen the shock wave.

The protection measures listed above will be more effective if they are applied in a complex manner, and it is always possible to neutralize the unpleasant consequences of water hammer and extend the life of pipes and household appliances.