Moulders can relieve the pressure with connectors

Manufacturer of connection and clamping products, Stäubli, has developed connectors with in-built pressure relief systems, which it says can provide a solution to the problem of hydraulic circuits retaining a level of residual pressure after operating.

Stäubli says that many hydraulic circuits on injection moulding machines, core pulling, for example, may retain residual pressure in the circuit after the planned operation has been completed. This can cause significant problems with connecting, especially where standard hydraulic connectors have been used. Standard connectors do not incorporate a pressure relief mechanism that will depressurise the circuit to allow connection to be made easily and securely.

Alarmingly, says Stäubli, users frequently resort to potentially dangerous practices to make the connection, such as hitting the connector’s valve with a hammer or screwdriver to release a small amount of fluid allowing the valve to operate and a connection to be made. This type of mistreatment can seriously damage the connector reducing its operational effectiveness and service life, cause leaks in operation due to damaged seals, and potentially cause dangerous accidental disconnection whilst under pressure.  Alternatively, some users may unscrew the back adapter of the connector to relieve the pressure in the circuit, but this also can be dangerous and cause operational problems through the uncontrolled release of high-pressure fluid.

Stäubli has therefore developed a range of SBA connectors that have a central relief valve to automatically opens the valve on connection, safely releasing the volume of fluid necessary to allow the backward movement of the valve permitting easy connection.  It says the connector is undamaged and the circuit integrity is maintained. 

There are many injection moulding applications where the facility to safely release residual circuit pressure is an advantage, high pressure core pulling systems for example. Stäubli says similar pressure relief systems are available on its other hydraulic connectors; for example the CBX range and for high-pressure hydraulic circuits the SBX range.