How to determine whether the Manifold block check valve is damaged
Common faults and handling methods of check valve:
1. The disc is broken
2. Medium reverse flow
The cause of disc breakage is:
Check valve before and after the medium pressure in close balance and each other “saw” state, disc often and seat flap, some brittle materials (such as cast iron, brass, etc.) made of disc is broken.
The way to prevent is to use the disc for the ductile material of the one-way valve.
The reasons for medium backflow are:
1). Sealing surface is damaged;
2). Insert impurities. Reverse flow can be prevented by repairing the sealing surface and cleaning impurities.
3. The check valve does not work
This fault refers to the reverse oil can also pass through the field check valve, but sometimes the positive oil can not pass.
First check the spool, because the burrs on the edge of the spool are not clean, the one-way valve is stuck in the open position, or the gap between the outer diameter of the spool and the inner diameter of the valve hole is too small.
Seat: there is dirt or breach at the contact line with the valve core. At this time, it can be cleaned or replaced by knocking out the seat.
Inspection of valve body:
There are burrs or impurities on the edge of the grooves in the valve body hole, and the valve core of the check valve is stuck in the open position. It usually returns to normal after cleaning.
Impurities into the valve body hole and the spool fit clearance and stuck spool, this kind of fault is more common, the same clean after the general recovery.
The gap between the outer diameter of the spool and the inner diameter of the valve hole is too large, so that the offset axis of the spool is too large, causing leakage. At this time, the valve core should be redeveloped or replaced.
4. The leakage in the check valve increases
The causes and exclusions are as follows:
This fault refers to the pressure oil reverse into the field one-way valve, the one-way valve cone valve or steel ball can not be strictly closed oil leakage, some oil from the oil inlet outflow. This failure is more likely to occur at low pressures or is more severe than at high pressures.
The contact line or surface of the valve core and the seat is not close. The reasons for non-tightness are as follows: dirt sticks in the contact of the valve core and the seat, because of too long time, and the contact line or surface wear of the seat, there are deep grooves or straight lines.
When the one-way valve is reassembled, the spool or steel ball is not assembled according to the original sample, resulting in a certain dislocation, and the contact position between the spool and the seat is changed.
One-way valve in long-term use of natural wear, so that the valve core and valve body with the gap is too large, beyond the specified range, resulting in leakage.
If necessary, the check valve should be disassembled and cleaned. Check the viscosity and cleanliness of hydraulic system oil.
Check valve spring should be replaced if damaged or over the service life.