System for adjusting rate of spool centering in a pilot-controlled hydraulic spool valve
The disclosure is directed to an apparatus and system for adjusting rate of spool centering in a pilot-controlled hydraulic spool valve. The apparatus includes a first pilot port and a second pilot port. The apparatus includes a first valve port and a second valve port. The apparatus also includes a first hydraulic circuit connecting the first pilot port and the first valve port, wherein the first hydraulic circuit, based on a hydraulic fluid pressure of the second pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition. The apparatus further includes a second hydraulic circuit connecting the second pilot port and the second valve port, wherein the second hydraulic circuit, based on a hydraulic fluid pressure of the first pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition.
1. An apparatus for adjusting rate of spool centering in a pilot-controlled hydraulic spool valve, the apparatus comprising:
a first pilot port adapted to connect to a first pilot port of a pilot section;
a second pilot port adapted to connect to a second pilot port of the pilot section;
a first valve port adapted to connect to a first control port of a hydraulic spool valve;
a second valve port adapted to connect to a second control port of the hydraulic spool valve;
a first hydraulic circuit connecting the first pilot port and the first valve port, wherein the first hydraulic circuit, based on a hydraulic fluid pressure of the second pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition; and
a second hydraulic circuit connecting the second pilot port and the second valve port, wherein the second hydraulic circuit, based on a hydraulic fluid pressure of the first pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition,
wherein:
the first hydraulic circuit comprises a bypass branch and a controlled-flow branch, wherein the bypass branch and the controlled-flow branch are in parallel,
the bypass branch of the first hydraulic circuit comprises a pilot-controlled check valve, a pilot port of the pilot-controlled check valve configured to connect to the second pilot port,
the controlled-flow branch of the first hydraulic circuit comprises a flow control valve,
in response to a high pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in an open state, so that the first hydraulic circuit is in the unrestricted-flow condition, and
in response to a low pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in a normal state, so that the first hydraulic circuit is in the controlled-flow condition.
2. The apparatus according to claim 1 , wherein:
in response to a high pilot pressure of the second pilot port, the first hydraulic circuit is in the unrestricted-flow condition; and
in response to a low pilot pressure of the second pilot port, the first hydraulic circuit is in the controlled-flow condition.
3. The apparatus according to claim 2 , wherein:
when the first hydraulic circuit is in the unrestricted-flow condition, pilot hydraulic fluid is configured to flow unrestrictedly in both directions between the first pilot port and the first valve port; and
when the first hydraulic circuit is in the controlled-flow condition, the pilot hydraulic fluid is configured to flow unrestrictedly in a direction from the first pilot port to the first valve port, and flow restrictedly at a first flow rate in a direction from the first valve port to the first pilot port, wherein the first flow rate is adjustable.
4. The apparatus according to claim 1 , wherein:
in response to a high pilot pressure of the first pilot port, the second hydraulic circuit is in the unrestricted-flow condition; and
in response to a low pilot pressure of the first pilot port, the second hydraulic circuit is in the controlled-flow condition.
5. The apparatus according to claim 4 , wherein:
when the second hydraulic circuit is in the unrestricted-flow condition, pilot hydraulic fluid is configured to flow unrestrictedly in both directions between the second pilot port and the second valve port; and
when the second hydraulic circuit is in the controlled-flow condition, the pilot hydraulic fluid is configured to flow unrestrictedly in a direction from the second pilot port to the second valve port, and flow restrictedly at a second flow rate in a direction from the second valve port to the second pilot port, wherein the second flow rate is adjustable.
6. The apparatus according to claim 1 , wherein:
when the pilot-controlled check valve of the first hydraulic circuit is in the open state, the pilot-controlled check valve allows hydraulic fluid flowing unrestrictedly in both directions; and
when the pilot-controlled check valve of the first hydraulic circuit is in the normal state, the pilot-controlled check valve blocks hydraulic fluid flowing in a direction from the first valve port to the first pilot port, and allows hydraulic fluid flowing unrestrictedly in a direction from the first pilot port to the first valve port.
7. The apparatus according to claim 6 , wherein:
the pilot-controlled check valve comprises a spring-loaded pilot-controlled check valve; and
the flow control valve comprises an adjustable flow control valve.
8. The apparatus according to claim 6 , wherein:
the second hydraulic circuit comprises a bypass branch and a controlled-flow branch;
the bypass branch of the second hydraulic circuit comprises a pilot-controlled check valve, a pilot port of the pilot-controlled check valve configured to connect to the first pilot port;
the controlled-flow branch of the second hydraulic circuit comprises a flow control valve; and
wherein:
in response to a high pilot pressure of the first pilot port, the pilot-controlled check valve of the second hydraulic circuit is configured to be in an open state, so that the second hydraulic circuit is in the unrestricted-flow condition, and
in response to a low pilot pressure of the first pilot port, the pilot-controlled check valve of the second hydraulic circuit is configured to be in a normal state, so that the second hydraulic circuit is in the controlled-flow condition.
9. A device for adjusting rate of spool centering in a pilot-controlled hydraulic spool valve, the device comprising:
a manifold comprising:
a first pilot port adapted to connect to a first pilot port of a pilot section,
a second pilot port adapted to connect to a second pilot port of the pilot section,
a first valve port adapted to connect to a first control port of a hydraulic spool valve, and
a second valve port adapted to connect to a second control port of the hydraulic spool valve;
a first hydraulic circuit disposed inside the manifold, the first hydraulic circuit connecting the first pilot port and the first valve port, wherein the first hydraulic circuit, based on a hydraulic fluid pressure of the second pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition; and
a second hydraulic circuit disposed inside the manifold, a second hydraulic circuit connecting the second pilot port and the second valve port, wherein the second hydraulic circuit, based on a hydraulic fluid pressure of the first pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition,
wherein:
the first hydraulic circuit comprises a bypass branch and a controlled-flow branch, wherein the bypass branch and the controlled-flow branch are in parallel,
the bypass branch of the first hydraulic circuit comprises a pilot-controlled check valve, a pilot port of the pilot-controlled check valve configured to connect to the second pilot port,
the controlled-flow branch of the first hydraulic circuit comprises a flow control valve,
in response to a high pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in an open state, so that the first hydraulic circuit is in the unrestricted-flow condition, and
in response to a low pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in a normal state, so that the first hydraulic circuit is in the controlled-flow condition.
10. A system for adjusting rate of spool centering in a pilot-controlled hydraulic spool valve, the system comprising:
a pilot valve configured to receive control signal from an operator;
a flow control device configured to receive hydraulic fluid from the pilot valve;
a main hydraulic valve configured to receive hydraulic fluid from the flow control device; and
wherein the flow control device comprises:
a first pilot port adapted to connect to a first pilot port of the pilot valve,
a second pilot port adapted to connect to the second pilot port of the pilot valve,
a first valve port adapted to connect to a first control port of the main hydraulic valve,
a second valve port adapted to connect to a second control port of the main hydraulic valve,
a first hydraulic circuit connecting the first pilot port and the first valve port, wherein the first hydraulic circuit, based on a hydraulic fluid pressure of the second pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition, and
a second hydraulic circuit connecting the second pilot port and the second valve port, wherein the second hydraulic circuit, based on a hydraulic fluid pressure of the first pilot port, comprises one of a controlled-flow condition and an unrestricted-flow condition,
wherein:
the first hydraulic circuit comprises a bypass branch and a controlled-flow branch, wherein the bypass branch and the controlled-flow branch are in parallel,
the bypass branch of the first hydraulic circuit comprises a pilot-controlled check valve, a pilot port of the pilot-controlled check valve configured to connect to the second pilot port,
the controlled-flow branch of the first hydraulic circuit comprises a flow control valve,
in response to a high pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in an open state, so that the first hydraulic circuit is in the unrestricted-flow condition, and
in response to a low pilot pressure of the second pilot port, the pilot-controlled check valve of the first hydraulic circuit is configured to be in a normal state, so that the first hydraulic circuit is in the controlled-flow condition.
11. The system according to claim 10 , wherein:
when the first hydraulic circuit is in the unrestricted-flow condition, pilot hydraulic fluid is configured to flow unrestrictedly both directions between the first pilot port and the first valve port;
when the first hydraulic circuit is in the controlled-flow condition, the pilot hydraulic fluid is configured to flow unrestrictedly in a direction from the first pilot port to the first valve port, and flow restrictedly in a direction from the first valve port to the first pilot port;
when the second hydraulic circuit is in the unrestricted-flow condition, pilot hydraulic fluid is configured to flow unrestrictedly both directions between the second pilot port and the second valve port; and
when the second hydraulic circuit is in the controlled-flow condition, the pilot hydraulic fluid is configured to flow unrestrictedly in a direction from the second pilot port to the second valve port, and flow restrictedly in a direction from the second valve port to the second pilot port.