Check valves: types, functions, etc.
Check valves are essential hydraulic components used in various industries and applications. They control the volume flow or flow rate by blocking it in one direction and releasing it in the opposite direction. In doing so, they contribute significantly to the efficiency, safety and performance of hydraulic systems.
The diverse designs and special configurations of this valve type enable a wide range of functions. For example, the valves serve as a bypass valve to bypass a filter or a restriction in one direction. They are used as a preload valve to create a certain back pressure in the outlet.
It is also common to use it as a retention valve to prevent an oil column from draining and thus preventing unwanted movement of a consumer.
The areas of application for check valves range from mobile work equipment such as agricultural and forestry machinery, construction machinery and municipal work equipment to industrial applications.
In this article, you will learn everything about the functions and possible applications of check valves. Immerse yourself in the world of valve technology. Discover how the components help to make hydraulic systems more efficient, safer and more powerful. Look forward to an insight into the wide range of possible applications and the technology behind the key components in hydraulic technology.
How do check valves work?
Check valves are hydraulic components. They ensure that the volume flow or flow rate in a hydraulic circuit is blocked in one direction and released in the opposite direction. This function is achieved by various mechanisms and designs. The most common are cone-shaped or ball-shaped poppet valves. These designs guarantee low-leakage or completely leakage-free blocking.
Depending on the design, the valves can perform different functions. In the case of check valves, a flow direction is blocked. Pilot-operated check valves can be used to lock pressurized operating circuits and can also be opened in the locking direction. Shuttle valves transmit the higher pressure signal from two pressure sources and shut off the two pressure sources from each other.
The valves can be designed as screw-in cartridges, inline valves or as sandwich plate designs according to ISO4401. Special designs for pipeline installation also exist. Spring preload plays an important role in the operation of check valves, as it affects the closing and opening forces. In the case of check valves with low spring preload, they can also be used as post-suction valves to prevent cavitation.
The functions of check valves at a glance
- Blocking of a volume flow in one direction, release in the opposite direction
- Use as a bypass valve to bypass filters or throttling points
- Use as a retention valve to prevent unwanted movements of consumers
- Forwarding of pressure signals and load pressures, for example in load-sensing systems
- Use of pilot-operated check valves to shut off working circuits under pressure
How are check valves designed?
Check valves are available in various designs, which differ in terms of their construction and mode of operation. A common design is the cone-shaped or ball-shaped poppet design, in which a cone or ball seat serves as the locking and opening mechanism, respectively.
The assembly of check valves can be done in different ways. One possibility is to use screw-in cartridges, where the valve is screwed directly into a corresponding thread. This design saves space and allows easy installation.
Another option is the sandwich design, where the valve is mounted between two other hydraulic components. The ISO4401 intermediate plate design is a common variant of the sandwich design and conforms to the standardized dimensions for such applications.
Finally, check valves can also be designed for in-line or pipeline installation. This design can be integrated directly into a pipeline or line. The design allows flexible adaptation to different system requirements and requires no additional adapters or mounting elements.
The various designs of check valves
Check valves are available in various designs to meet different requirements in hydraulic systems. One common variant is check valves such as the SC1F-A2 from ARGO-HYTOS, which block the volume flow in one direction. These valves can be used in various functions, for example
- as a bypass valve to bypass a filter or throttling point in one direction and allow flow in the other direction.
- as a preload valve, which creates a certain back pressure in the drain to regulate the system pressure.
- as a retaining valve that prevents the oil column from draining and thus stops the unwanted movement of a consumer.
- to transmit pressure signals or load pressures, for example in load sensing systems that adjust the pressure to the actual load.
- as a suction valve with low spring preload, used to prevent cavitation and ensure a continuous flow of liquid.
Another design of check valves are pilot-operated check valves such as the IC5H from ARGO-HYTOS. These valves can shut off pressurized working circuits and can also be opened in the shut-off direction. They are ideally suited for preventing creep movements of hydraulically clamped consumers and thus provide additional safety and flexibility in hydraulic systems.
Shuttle valves such as the LV1-043 from ARGO-HYTOS represent another special form of check valves. They transmit the higher pressure signal from two pressure sources and shut off the two pressure sources from each other. They have a fast response time to load changes. They are therefore particularly suitable for applications where rapid adaptation to changing operating conditions is required.
Universal use of check valves in mobile and industrial applications
Check valves play a crucial role in the control and safety of hydraulic systems in a wide range of applications. Their flexibility and versatility make them an optimal solution in both mobile equipment and industrial applications. Alongside hydraulic pumps and flow control valves, check valves enable the functionality of efficient hydraulic systems.
In agriculture and forestry, check valves are used, for example, in tractors, combine harvesters, log splitters or forestry machines. There, they control the volume flow in various working circuits. They ensure safe and efficient operation of these machines by directing the fluid flow in a desired direction. They also prevent unwanted movements.
Construction machinery such as excavators, wheel loaders, rollers or cranes also benefit from the advantages of check valves. They enable precise control and stability during demanding tasks such as lifting, lowering or rotating loads. Municipal work machines such as sweepers, snow plows or garbage trucks also rely on check valves to operate their hydraulic systems efficiently and safely.
The valves are also indispensable in industrial applications. They are used in production plants, production lines, machine tools or hydraulic presses, to name just a few examples. In these applications, check valves are essential. This is because they ensure the smooth operation of machinery and equipment and enable precise control of hydraulic systems.
Get in touch with our experts now
Check valves are essential hydraulic components used in a variety of industries and applications. Their diverse designs and functions contribute significantly to the efficiency, safety and performance of hydraulic systems. The different designs and mounting options allow flexible adaptation to specific system requirements.
ARGO-HYTOS is known for high-quality and reliable check valves. We would be happy to advise you in a personal meeting on the possibilities offered by our check valves for your individual applications. The best thing to do is to contact us right away. We look forward to supporting your company with technical components from ARGO-HYTOS soon!