Check valves
Check valves ensure required function and prevent damage to machines
Check valves and non-return valves ensure required function and prevent damage to machines
Check valves allow media to flow in pipelines in one direction only and prevent a reversal of the flow direction. In the event of backflow in the other direction, non-return valves close automatically by means of a closing element, which is closed by a spring when the pressure drops. If the pressure of the medium is higher than the spring force, the closing element remains open. Only when the direction of flow is correct do the non-return valves open again.
This function is required in many applications with compressible and non-compressible media. Various closing elements are used to ensure the blocking function of a non-return valve. Depending on the technical requirements of the check valve, we use balls, pistons, discs and lip seals.
When choosing the right check valve for your application, the most important parameters include the medium, pressure, flow rate, material, installation dimensions, dimension and connections. In addition to a wide range of standard products, TRI-MATIC offers special designs for your individual application. Many things are possible here and can be defined together with you in the project phase.
Check valves and non-return valves are installed in many systems in building services and pneumatics, in humidification systems and pipelines or when filling and emptying tanks, in order to ensure the required function and prevent damage to machines or systems.
Types and operation of non-return valves
A non-return valve allows a fluid to flow in only one direction and closes automatically as soon as the flow stops or reverses. In hydraulics, it protects pumps, cylinders and control blocks from uncontrolled backflow and maintains system pressure.
An overview of check valve designs
Different designs are used depending on the application, medium and nominal size.
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FAQ
The four main types are:
- Spring-loaded non-return valves: The cone or disc is held closed by a spring. Standard in hydraulics and pneumatics.
- Swing check valves: A pivoting flap for large nominal diameters with low pressure drop, usually with a metal-to-metal seal.
- Ball check valves: A ball seals the passage. Compact, low-maintenance, for smaller nominal diameters.
- Diaphragm check valves: Can be designed without dead space; preferred in the food and pharmaceutical industries.
TRI-MATIC offers all these types in various materials and nominal diameters. You can find an overview under non-return valves.
In a hydraulic system, the non-return valve allows the fluid to pass only in the working direction. As soon as the pressure on the inlet side exceeds the set opening pressure, the fluid pushes the seat or ball open against the spring force. If the inlet pressure falls below the back pressure, the valve closes automatically, thereby preventing backflow. This protects pumps from pressure surges and ensures holding functions on hydraulic cylinders.
For the food and drink industry, stainless steel non-return valves with FDA-compliant elastomer seals are required. Hygienic process connections such as DIN 11851 milk pipe screw connections, weld-on ends or TRI-CLAMP enable residue-free cleaning. The valves must withstand CIP and SIP processes. TRI-MATIC can advise you on selecting the right variant for your process application.
Both components prevent a fluid from flowing in the wrong direction. A non-return valve is the general technical term for all valves that restrict flow to a single direction. A backflow preventer specifically refers to standard-compliant fittings for drinking water installations that prevent the backflow of contaminated water into the drinking water supply. In industrial settings, such as in pipework systems, however, the term non-return valve is usually used.
Valves from TRI-MATIC
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