19.5: The Operation and Schematic Symbol of an Integral Check Valve
- Page ID
- 117090
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In hydraulic systems, we often need to allow flow in one direction while blocking it in the other. When working with sequence valves, one way to manage reverse flow is by adding a separate bypass check valve, which is plumbed around the sequence valve externally. This solution works, but it takes up space and adds plumbing complexity.
To simplify things, many manufacturers now offer sequence valves with built-in check valves, known as integral check valves. These perform the same function as the external check valve but are packaged neatly within the body of the sequence valve itself. This reduces the number of connections, saves space in the circuit, and simplifies assembly and troubleshooting.
The schematic symbol for a sequence valve with an integral check valve includes a small check valve drawn in parallel with the main valve path. This clearly shows that flow is permitted in one direction (usually reverse), bypassing the main valve's control spool.