What Is Hydraulic Shock? Analysis of Its Causes

Hydraulic shock, also known as the water hammer effect, is a pressure fluctuation in a hydraulic system caused by a sudden change in fluid velocity. Hydraulic shock can cause a rapid increase in pressure in the system, which can cause damage to pipes, valves, hydraulic components, etc. This article will provide an in-depth analysis of the definition, causes and possible hazards of hydraulic shock, and provide preventive measures to help you avoid the impact of this phenomenon on your hydraulic system.

What is hydraulic shock?

Hydraulic shock refers to the sudden change in the flow speed of the fluid in the hydraulic system, which leads to sharp fluctuations in the internal pressure of the system. This shock usually occurs during operations such as valve closing and pump starting or stopping. The main characteristic of hydraulic shock is a sudden rise in pressure, and the system components may be damaged because they cannot withstand too much pressure.

Hydraulic shock not only affects the stability of the hydraulic system, but also may reduce the operating efficiency of the equipment, accelerate the wear of the components, and in serious cases may lead to system failure or even shutdown.

Causes of hydraulic shock

Hydraulic shocks can occur for a variety of reasons, the following are the most common:

The valve suddenly closes or opens

When the valve in the hydraulic system is suddenly closed or opened, the flow rate of the fluid will change dramatically, resulting in a hydraulic shock. Especially when the valve is closed, the inertial action of the fluid will cause high pressure fluctuations.

The hydraulic pump starts and stops or the load changes sharply

When the hydraulic pump starts or stops, it will cause the liquid flow to mutate, especially when the load changes sharply, and the possibility of hydraulic shock is greater.

A bubble or gas in a pipe

If there is air or bubbles in the hydraulic system, these gases will compress or burst when the pressure of the hydraulic system fluctuates violently, which will aggravate the hydraulic shock phenomenon.

The system design is not reasonable

If the pipeline layout of the hydraulic system is not reasonable, the pipeline is too long, too many elbows, or the improper selection of valves and hydraulic components, it will also increase the risk of hydraulic shock.

Oil return pipeline design problem

If the return line has a design defect (such as being too long or too bent), the fluid flow is uneven and can lead to hydraulic shock.

Hydraulic fluid properties change

When the temperature or viscosity of the hydraulic oil changes, the flow characteristics of the fluid will also change, which may exacerbate the effects of hydraulic shock.

Overload or overspeed operation

If the hydraulic system is operating under overload or excessive speed, drastic changes in flow or pressure will directly lead to hydraulic shock.

Consequences of hydraulic shock

Hydraulic shock not only affects the efficiency of the hydraulic system, but also may cause serious damage to the equipment, including the specific consequences:

Pipe rupture: Hydraulic shock can cause pipes or joints to rupture due to pressure fluctuations.

Seal damage: High pressure fluctuations can cause excessive pressure on the seal, resulting in leakage or damage.

Hydraulic component damage: Components such as hydraulic pumps, valves and hydraulic cylinders may fail due to excessive impact force.

Reduced system efficiency: Hydraulic shocks can cause instability in the system, increase noise and vibration, and reduce overall efficiency.

How to avoid hydraulic shock?

In order to reduce the occurrence of hydraulic shock, the following methods can be taken:

Slow opening valve

Use a buffer valve or properly control the opening and closing speed of the valve to avoid sharp changes in fluid velocity and reduce the occurrence of shocks.

Optimize the hydraulic pump start and stop process

Smooth start and stop of hydraulic pump is ensured by soft start device or gradual load control to avoid abrupt flow rate.

Use energy dissipators or accumulators

Energy dissipators or accumulators are installed in the system to effectively absorb pressure fluctuations and reduce the impact of hydraulic shocks on the system.

Rational design of pipeline system

Ensure that the hydraulic pipe length is moderate, avoid excessive elbows and sharp turns, and reduce the instability of fluid flow.

Control the temperature and viscosity of hydraulic fluids

Maintain the appropriate temperature and viscosity of the oil to ensure the stability of the liquid flow and reduce the risk of uneven flow.

Check and maintain the system regularly

Regular inspection of valves, seals, pipes and components in the hydraulic system, timely detection and elimination of potential risks to ensure long-term stable operation of the system.

Sum up

Hydraulic shock is a kind of pressure fluctuation caused by sudden fluid flow in hydraulic system, which can cause serious damage to hydraulic components and piping system. By understanding the causes of hydraulic shock and taking appropriate preventive measures, such as reasonable design of the system, slow operation of valves and the use of energy dissipators, the impact of hydraulic shock on the system can be effectively reduced to ensure the efficient and stable operation of the hydraulic system.

If you would like to learn more about hydraulic system maintenance and optimization tips, please continue to follow our articles, or contact us for professional technical support and advice.