MODEL : PV (Size 40-80)

Operation and Maintenance Instructions :

Polyhydron make Prefill and Exhaust valves are reliable and hence require very little attention from the user. However it is necessary that following points must be kept in mind while storage, operation, commissioning and maintenance.

Storage :

It is necessary that during storage the valve must be well lubricated and properly covered. This will prevent ingress of dirt/dust in the working mechanism of the unit and during commissioning it will be easy to install the same.

Operation :

The Prefill and Exhaust valves are designed specifically to eliminate the need for high volume pumps on large press circuits

Seat type construction.

Allows free flow from port ‘A’ to port ‘B’. Flow from port ‘B’ to port ‘A’ can be had by applying pilot pressure to it’s port ‘X’.

Decompression feature enables the valve to open in two stages progressively allowing smooth and rapid exhaust of the compressed oil.

The opening and closing of the valve can be influenced by providing Throttle Cum Check valve in the port ‘X’.

Commissioning :

During commissioning, the Prefill and Exhaust valves do not need any special attention but following points must be kept in mind.

Port ‘A’ must be connected to tank, port ‘B’ to pressure side and port ‘X’ to the pilot pressure.

Cap screws and corresponding tightening torque should be used as mentioned in the Data sheets.

O’ring ( supplied with the valve separately ) should be first fitted on the guide. The valve is then slowly and carefully placed inside the cavity. This will ensure the proper sealing of the valve.

Maintenance :

The Prefill and Exhaust valves do not need major attention, however it is necessary that following points must be kept in mind for proper working of the valves.

The oil must be of prime quality and clean as per ISO 16/13 and must be changed periodically. Contaminated oil may lead to the wear and tear of both pilot piston and housing there by increasing the clearance. This results in improper working of the valve.

The oil temperature must be within the specified range. i.e. –20 to +70 degree Celsius.

Updated on February 04, 2015 03:05 pm .