Hydrant valve pilot with detachable actuator

A pilot valve actuator for use with a hydrant valve has a pilot valve and a removable actuator. The pilot valve blocks communication between a primary hydrant chamber and a piston chamber when in a closed position. Under pressure, the actuator opens the pilot valve against its biasing force permitting the flow of fluid between the hydrant chamber and the piston chamber. The pilot valve is permanently attached to the hydrant valve. The actuator is removable from the pilot valve by a quick disconnect mechanism permitting storage of the actuator remote from the hydrant valve.

BACKGROUND OF THE INVENTION

This invention relates to hydrant valves or shut-off valves commonly used in aircraft fueling. More particularly, this invention relates to a pilot valve actuator for opening or closing a hydrant valve.

A hydrant valve used in aircraft fueling delivers fuel by connecting fuel storage through an underground pipeline at its inlet to an aircraft through a fueling vehicle equipped with a hydrant valve coupler and hose system at its outlet. For safety reasons, to avoid a collision with an aircraft or a supporting vehicle around the aircraft, hydrant valves are, as a rule, installed in a hydrant pit below ground level. A hydrant valve is designed to be opened or closed by the fueling operator from a distance. This requirement is causal so that if a fuel spill occurs in the vicinity of the hydrant pit, the fueling operator has the ability to terminate the flow of fuel by closing the hydrant valve from a safe distance.

Since electric power is normally lacking in the hydrant pit due to the concern over ignition of the fuel, the hydrant valve cannot be controlled electromechanically. The most commonly accepted method for controlling the opening and closing of hydrant valves is the utilization of pressure, either pneumatic or hydraulic, such that the fueling operator can apply or vent pressure to the hydrant valve through a handle valve and command hose which is commonly called a “deadman”. Due to the high pressure and flow rates sustained by hydrant valves, practically all hydrant valves are pilot operated; that is, the main hydrant valve will be opened or closed by actuating a smaller pilot valve installed in the main hydrant valve.

In prior art hydrant valves, a pilot valve actuator is permanently installed directly on the body of the main hydrant valve. Pneumatic or hydraulic pressure is applied to the actuator through a quick disconnect pressure fitting.

FIG. 1depicts a prior art hydrant valve10. The hydrant valve includes a hydrant body12which encloses a primary hydrant chamber14. This hydrant chamber14is connected to an inlet16and an outlet18. The hydrant body12is secured to a fixed rigid surface by means of connectors13. A fuel supply (not shown) is introduced to the hydrant chamber14through the inlet16. A fueling vehicle (not shown) receives fuel from the hydrant valve10through the outlet18.

A piston20is located within the hydrant chamber14and movable between opened and closed positions relative to the inlet16. When the piston20is in the closed position, it prevents the flow of fuel through the inlet16. A chamber22is located within the piston20. The piston chamber22is in communication with the inlet16through a passageway24. The piston chamber22is isolated from the hydrant chamber14by seals26and28and a pilot valve30as will be described below. Because the piston chamber22is in communication with the inlet16, the pressure within the chamber22is equalized with the pressure in the inlet16. In addition, because the chamber22is isolated from the hydrant chamber14as described, the pressure in the hydrant chamber14is negligible. The piston20remains in the closed position because of the equalized pressure exerted in the piston chamber22and the opposing pressure exerted in the inlet16(see arrows inFIG. 1).

The hydrant valve10also includes a pilot valve30and an actuator40. The pilot valve30and actuator40are essentially permanently attached to the hydrant valve10in that they cannot be removed without disassembly of the system. As shown inFIG. 2, the prior art pilot valve30blocks communication between the hydrant chamber14, the piston chamber22, and the passageway24. The pilot valve30comprises a pilot valve stem32, a pilot valve seat34and a pilot valve return spring36. The pilot valve return spring36biases the pilot valve stem32in a closed position against the pilot valve seat34. The pilot valve30also includes pilot openings38adjacent the pilot valve seat34. When the pilot valve stem32is against the pilot valve seat34, flow through the pilot openings38is obstructed. The prior art actuator40comprises a pressure supply adaptor42, an actuator plunger44, an actuator plunger stem46, and an actuator plunger return spring48. The pressure supply adaptor42includes a quick disconnect connector43to connect a source of pressure medium (not shown), i.e., pneumatic or hydraulic fluid. The actuator40is sealed to prevent the transfer of pressure medium from the actuator40to the pilot valve30.

In the absence of a pressure supply, the actuator plunger return spring48biases the actuator plunger44in a closed position. When the actuator plunger44is in the closed position the actuator plunger stem46extends into the pilot valve30. The actuator plunger stem46is connected to the pilot valve stem32. The combination of the biasing forces from the actuator plunger return spring48and the pilot valve return spring36bias the pilot valve stem32in a closed position against the pilot valve seat34.

When a pressure medium is introduced through the pressure supply adaptor42, the actuator plunger44is moved into an open position against the biasing force of the actuator plunger return spring48. When the actuator plunger44moves into the open position, the actuator plunger stem46is withdrawn from the pilot valve30. As the actuator plunger stem46is withdrawn from the pilot valve30, the pilot valve stem32is moved from the closed position to the open position against the biasing force of the pilot valve return spring36. As the pilot valve stem32moves away from the pilot valve seat34, the pilot openings38are uncovered. The pilot openings38permit communication between the hydrant chamber14, the piston chamber22and the passageway24. When the hydrant chamber14, piston chamber22and passageway24are connected the once equal pressure in the piston chamber22and the inlet16are made unequal permitting the pressure of the fuel supply in inlet16to move the piston20into an open position. In this way, fuel is permitted to move from the inlet16through the hydrant chamber14to the outlet18.

This prior art hydrant valve presents a number of disadvantages. First, as previously mentioned, hydrant valves are normally installed in an open hydrant pit below ground level. This open exposure to the environment introduces various contaminants into the pit, such as water, spilled fuel, debris, abrasives, etc. While the main hydrant valve itself is relatively well-sealed against such contaminants, the pilot valve and its actuator are easily damaged by the contaminants due to their mechanical nature and the need to be open to the atmosphere.

Second, there are various means of applying the pressure necessary to activate a pilot valve actuator. The pressure could be supplied pneumatically using pressurized air from a compressor on the fueling vehicle. The pressure could also be supplied hydraulically utilizing pressurized fluid stored on the fueling vehicle. In some airports, some vehicles may use pneumatic pressure and other vehicles may use hydraulic pressure. In the prior art hydrant valves described above where the actuator is permanently affixed, various pressure media, i.e., air, fuel, oil, that remains in an actuator may be ingested into fueling vehicles causing cross-system contamination. Such contamination may cause equipment failure in the fueling vehicles.

Third, is a financial concern. It is inefficient for every hydrant valve in an airport to be equipped with a relatively expensive actuator. In the traditional setup, each hydrant valve at an airport carries a pilot valve and actuator. The work involved in maintaining and repairing the actuators on each hydrant valve at a single airport could pose a huge logistical problem. A single airport can have hundreds of hydrant valves. While many airports typically have hundreds of hydrant valves they have only a few tens of fueling vehicles to support them. It would be substantially less expensive to remove the actuator from the hydrant valve and install it on the fueling vehicles such that only a few tens of actuators would be required to control the hundreds of hydrant valves at an airport. This would reduce the initial investment required as the number of actuators are reduced and would also reduce the maintenance costs.

Accordingly, there is a need for a hydrant valve wherein the actuator is not exposed to contaminants by its constant presence in the open hydrant pit. Additionally, there is a need for a hydrant valve where an actuator will not be activated by different pressurized media thereby avoiding cross-system contamination. Further, there is a need for a hydrant valve that is economical in that only enough actuators are present to account for each fueling vehicle connectable to the hydrant valves. The present invention fulfills these needs and provides other related advantages.

SUMMARY OF THE INVENTION

The present invention relates to a pilot valve actuator for use with a hydrant valve. In particular, the invention provides for a hydrant valve including a primary hydrant chamber having an inlet and an outlet, a piston in the hydrant chamber movable between open and closed positions relative to the inlet, and a chamber disposed within the piston in communication with the inlet. A pilot valve is disposed between the primary hydrant chamber and the piston chamber, and an actuator is connected to the pilot valve. The actuator is removably connected to the pilot valve for selectively opening the pilot valve and thereby causing the piston to move from the closed to open position. The actuator is connectable to the pilot valve by a quick disconnect mechanism comprising an actuating collar, a collar return spring and latching elements on the actuator. The latching elements are mated to a connector on the pilot valve. The latching elements and mating connector may comprise latching lugs, threaded screws or a ball latch.

The actuator may be removed from the hydrant valve when the hydrant is not in use. The actuator may be controlled using pneumatic or hydraulic pressure and the actuator is sealed to prevent the transfer of actuator medium, i.e., pneumatic or hydraulic fluid, from the actuator to the pilot valve.

The pilot valve comprises a connector, a pilot valve stem, a pilot valve seat, a pilot valve return spring and a spring retainer. The mating of the pilot valve stem to the pilot valve seat when in the closed position blocks communication between the primary hydrant chamber and the piston chamber. The pilot valve return spring biases the pilot valve in the closed position.

The actuator comprises a pressure supply adaptor, an actuator plunger, an actuator return spring, an actuator body and a quick disconnect mechanism. The actuator operates the pilot valve through the application of pressure to the actuator plunger. The actuator plunger presses against the pilot valve stem in the pilot valve to move the pilot valve into an open position.

These and other aspects of the invention will be apparent to one skilled in the art in light of the following detailed description of the preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a pilot valve actuator for use with a hydrant valve. The pilot valve actuator of the present invention includes a novel pilot valve and a novel removable actuator for use with a hydrant valve.

As described above, a hydrant valve10consists of a hydrant body12, a primary hydrant chamber14, an inlet16and outlet18on the hydrant chamber14, a piston20, a piston chamber22, a passageway24, and seals26and28. The pilot valve actuator50of the present invention replaces the pilot valve30and actuator40of the prior art.

FIGS. 3-5depict the assembly and operation of the pilot valve actuator50. The pilot valve actuator50includes a pilot valve52and an actuator62. The pilot valve52is permanently attached to the hydrant body12as the pilot valve52in the prior art. The pilot valve52is disposed between the primary hydrant chamber14and the piston chamber22thereby blocking communication between the two chambers when the pilot valve52is in a closed position. The pilot valve52includes a valve stem54, a valve seat56, pilot openings57, a return spring58, a spring retainer59and a connector assembly60. When the valve stem54is moved away from the valve seat56, the pilot valve52moves into the open position permitting the flow of fuel from the piston chamber22to the hydrant chamber14through pilot openings57. The mechanism by which the valve stem54is moved away from the valve seat56will be described below.

The actuator62includes an actuator plunger64, a plunger return spring66, an actuator body68, a pressure supply adaptor70and a quick disconnect mechanism comprising a collar72, a collar return spring74and latching elements76. The actuator62is connectable to and removable from the pilot valve52through the mating of the quick disconnect mechanism72,74,76with the pilot valve connector assembly60. The latching elements76and mating connector60may include latching lugs, threaded screws or a ball latch. In operation, the collar return spring74maintains the collar72in an extended position. When the collar72is in an extended position it exerts a force on the latching elements76preventing them from disengaging a mated connector60. When the collar72is retracted against the biasing force of the return spring74, the latching elements76are permitted to disengage a mated connector60. In this way the actuator62is removable from the pilot valve52. The mechanism works in the reverse manner to connect the actuator62to the pilot valve52.

The actuator return spring66biases the actuator plunger64in a retracted or closed position. When a pressure medium, i.e., pneumatic or hydraulic fluid, is introduced through the pressure supply adaptor70, a force exerted on the plunger64moves the plunger to an extended or open position against the biasing force of the return spring66. When the plunger64is in the extended position, it engages the pilot valve stem54thereby moving the pilot valve52into an open position as described above.

The actuator62is preferably removed from the pilot valve52when the hydrant valve10is not in use. The actuator62presents a sealed environment preventing the transfer of pressure medium, i.e., pneumatic or hydraulic fluid, to the pilot valve52. When the actuator62is detached from the pilot valve52or when the actuator62is connected to the pilot valve52but no actuating pressure is applied through the adaptor70, the pilot valve52stays closed. Upon the application of actuating pressure through the adaptor70, the actuator62opens the pilot valve52as described above. Upon terminating actuating pressure through the adaptor70or detaching the actuator62from the pilot valve52, the pilot valve return spring58again biases the valve stem54against the valve seat56closing the pilot valve52and the hydrant valve10. The closure of the hydrant valve10will occur regardless of whether the actuating pressure through the adaptor70is terminated or the actuator62is removed from the pilot valve52while still under pressure. When the actuating pressure through the adaptor70is vented from the actuator62, the actuator plunger return spring66again biases the plunger64in its retracted position—ready for its next use.

Although an embodiment has been described in some detail for purposes of illustration, various modifications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.