Process and apparatus for filling a constant speed drive
AssigneeSundstrand Corporation
InventorJerome A. Mortenson
Life of this patent
Estimating the term…
Abstract
A service valve (10) is provided to provide an apparatus and method for filling a constant speed drive without overfilling and for preventing gas entrapment in the oil circuit of the drive. The valve (10) has a spool (12) movable in response to pressure from a filling fluid so as to connect the filling fluid with the drive circuit until a predetermined level has been reached at which point a signal is generated to allow the operator to remove the source of filling fluid. An air vent float valve (44) and a pressure switch (28) in the oil circuit allow the trapped gas to be vented from the oil circuit.
Claims16
A process for filling a hydraulic system with fluid under pressure in such a manner as to prevent overfilling while, during the filling process, permitting gas trapped in the system to escape, comprising the steps of:
- (a) connecting a valve with conduits of the system through ports in a casing of the valve such that a movable control piston within the casing can selectively communicate the conduits with the filling fluid;
- (b) connecting a source of the fluid under pressure to an inlet of the valve casing and thereby moving the control piston inside the valve casing to a position where selected conduits are selectively communicated with the filling fluid;
- (c) first permitting the filling fluid to flow through a first one of the ports connected by one of the conduits to an external circuit;
- (d) thereafter filling the valve with sufficient fluid to cause the fluid supplied to the external circuit to return to the interior of the valve casing through a return conduit connected between the external circuit and a second one of the ports in the valve casing;
- (e) directing the fluid returned to the interior of the valve from the external circuit through a third one of the ports which is connected to a conduit communicating with an air purging float valve and pressure responsive switch means;
- (f) further directing the fluid to a casing of the system until the casing is filled to the desired level;
- (g) creating a pressure build-up in the conduit communicating the air purging float valve and the third port until a predetermined pressure is reached;
- (h) causing the pressure responsive switch means to respond to a predetermined pressure as a result of the pressure build-up and to thereafter direct the filling fluid to an accumulator while providing a signal to an operator that a desired pressure has been reached and the system has been purged of trapped air;
- and
- (i) disconnecting the source of filling fluid from the inlet of the valve casing.
An apparatus for filling conduits of a hydraulic system with fluid under pressure in such a manner as to prevent overfilling while, during a filling operation, permitting gas trapped in the system to escape, comprising:
- (a) an external hydraulic circuit;
- (b) a valve including a casing with an inlet for connection to a source of fluid, a control piston slidable in the casing, biasing means for normally biasing the piston toward the inlet, and ports through the casing;
- (c) a first one of the ports communicating with the external circuit through a first conduit for supplying fluid under pressure from the inlet of the valve to the external circuit;
- (d) a second one of the ports communicating with the external circuit through a second conduit for returning the fluid under pressure from the external circuit to the interior of the casing where the slidable piston has an annular space defined by its circumference and the inner wall of the casing;
- (e) means in the control piston defining an annular space between the piston and an inner wall of the casing for selectively communicating the first and second of the ports during the filling operation when the piston has been moved in opposition to the biasing means;
- (f) air purging float valve;
- (g) an accumulator;
- (h) a case for the hydraulic system;
- (i) a third one of the ports in communication with the annular space of the selective communication means in the control piston also communicating with the case via a conduit through the float valve;
- (j) a pressure responsive switch means for sensing the pressure in the conduit associated with the air purging float valve and selectively admitting the fluid from the third of the ports to the accumulator, wherein during the filling operation the filling fluid under pressure is returned to the valve from the external circuit and is transmitted to the case until a predetermined pressure is reached, at which point the pressure responsive switch means directs the fluid to the accumulator and cause a signal to be transmitted to an operator to indicate that the filling operation is complete and entrapped gas has been removed from the system.
An apparatus for filling conduits of a hydraulic system with fluid under pressure in such a manner as to prevent overfilling while, during a filling operation, permitting gas trapped in the system to escape, comprising:
- a valve comprising an inlet for connection to a source of fluid, a control piston slidable in the casing, biasing means for normally biasing the piston toward the inlet, and ports;
- a first one of the ports serving to supply fluid under pressure from the valve, a second one of the ports serving to return the fluid under pressure to the interior of the valve;
- means for selectively communicating the first and second of the ports during the filling operation when the piston has been moved in opposition to the biasing means;
- and air purging float valve;
- an accumulator;
- a case for the hydraulic system;
- a third one of the ports operatively associated with the selective communication means and with the case;
- and pressure responsive switch means for sensing the pressure in a conduit associated with the air purging float valve and selectively admitting the fluid from the third of the ports to the accumulator, wherein, during the filling operation, the filling fluid under pressure is returned to the valve and transmitted to the case until a predetermined pressure is reached, at which point the pressure responsive switch means directs the fluid to the accumulator and causes a signal to be transmitted to an operator to indicate that the filling operation is complete and entrapped gas has been removed from the system.
Dependencies are inferred from the claim text.