Fuel-isolation system having rupture diaphragm

A fuel-isolation system includes a valve body that defines a flow passage that extends from an inlet to an outlet, a rupture diaphragm in the flow passage and fluidly sealing the inlet from the outlet, and an actuator situated adjacent the rupture diaphragm. The rupture diaphragm is integral with the valve body. The actuator includes a plunger that is configured to move and cause breach of the rupture diaphragm and thereby fluidly connect the inlet and the inlet.

BACKGROUND

Vehicles burn fuel for propulsion and/or orientation adjustment. In some types of vehicles, up until “activation” the fuel may be contained within an isolation section of a fuel system of the vehicle. The isolation section is robust in order to assure leak-free containment. Upon activation, the fuel is released from the isolation section such that the vehicle becomes operable for propulsion and/or orientation adjustment.

SUMMARY

A fuel-isolation system according to an example of the present disclosure includes a valve body that defines a flow passage extending from an inlet to an outlet and a rupture diaphragm integral to the valve body. The rupture diaphragm is in the flow passage and fluidly seals the inlet from the outlet. An actuator is situated adjacent the rupture diaphragm. The actuator includes a plunger that is configured to move and cause breach of the rupture diaphragm and thereby fluidly connect the inlet and the outlet. A propellant tank has an outlet attached to or integral to the inlet of the valve body.

In a further embodiment of any of the foregoing embodiments, the actuator is a thermal actuator.

In a further embodiment of any of the foregoing embodiments, the actuator is a wax actuator.

In a further embodiment of any of the foregoing embodiments, the plunger is a piston.

In a further embodiment of any of the foregoing embodiments, the plunger is configured to pierce the rupture diaphragm.

In a further embodiment of any of the foregoing embodiments, the rupture diaphragm has at least one score line.

In a further embodiment of any of the foregoing embodiments, the rupture diaphragm is curved.

A further embodiment of any of the foregoing embodiments includes a knife edge adjacent the rupture diaphragm and located on an opposite side of the diaphragm from the actuator.

In a further embodiment of any of the foregoing embodiments, the rupture diaphragm is welded to the valve body.

In a further embodiment of any of the foregoing embodiments, the rupture diaphragm is metallic.

In a further embodiment of any of the foregoing embodiments, in addition to the inlet and the outlet, the valve body defines a test port that opens into the flow passage and is fluidly connected with the outlet but not the inlet.

In a further embodiment of any of the foregoing embodiments, the outlet contains a filter.

In a further embodiment of any of the foregoing embodiments, the outlet contains a venturi.

A further embodiment of any of the foregoing embodiments includes a fuel tank connected with the inlet.

In a further embodiment of any of the foregoing embodiments, the propellant tank contains pressurized hydrazine.

In a further embodiment, the fuel isolation system is in any of the foregoing embodiments is in a vehicle.

DETAILED DESCRIPTION

Mechanisms that control the release of fuel from isolation sections of fuel systems in vehicles can be relatively complex. Such mechanisms must be reliably controlled and operational to activate the release of the fuel only at the desired time. As can be appreciated, in order to meet these requirements, such mechanisms may have relatively complicated designs. Although these solutions are effective, they may add expense, not only from the design itself, but also from installation steps and quality assurance measures. Along these lines, as will be apparent from the present disclosure, the unique fuel-isolation system herein seeks to provide a reliable, lost cost option to control activation of the release of fuel.

FIG.1schematically illustrates an example fuel system20(“system20”). As shown, the system20is in a vehicle, which is generally designated at22. For example, the vehicle22is a satellite, although this disclosure may be applied to other types of vehicles.

The system20includes an isolation valve24that is fluidly connected with an outlet25of a fuel tank26that may contain fuel26a, such as hydrazine. For example, the outlet25is attached to or integral to the isolation valve24. The isolation valve24serves to isolate the fuel26afrom a remainder of the fuel system20, which is generally designated at28. As will be understood, the remainder of the fuel system28may include fluid lines, valves, injectors, and other engine or thruster components that are well understood in the field.

The isolation valve24is formed of a valve body30. The valve body30is formed of a metallic alloy and may be of single- or multi-piece construction as long as it is leak-free under the pressure and use conditions. The valve body30includes an inlet32, an outlet34, and a flow passage36that extends from the inlet32to the outlet34. The inlet32is welded to the outlet25of the fuel tank26. In this example, the isolation valve has an “elbow” configuration such that the flow passage36turns approximately 90 degrees. It is to be appreciated, however, that the geometry of the isolation valve24and flow passage36path may be varied.

The isolation valve24further includes a rupture diaphragm38located in the flow passage36and an actuator40situated adjacent the rupture diaphragm38. The rupture diaphragm38fluidly seals the inlet32from the outlet34. The actuator40includes a plunger40athat is configured to move in an extended manner (as represented at arrow42). The actuator40is situated such that the plunger40ais extendable over a stroke that intersects with the rupture diaphragm38. For example, the stroke of about one-half inch and exerts about 100 pounds of force. The rupture diaphragm38is frangible under the impact of the plunger40asuch that extension of the plunger40acauses breach of the rupture diaphragm38.

In one example, the actuator40is a thermal actuator. One example thermal actuator is a wax actuator, such as a paraffin actuator. A thermal actuator converts thermal energy into mechanical energy in the form of extension of the plunger40a. In one example based on paraffin, the actuator40includes a heater that is operable to heat paraffin wax, such as to a temperature above the melting temperature of the paraffin wax (about 176° F.). The wax melts and expands, and the expansion causes extension of the plunger40a. As will be appreciated, other types of actuators may be used, however, the wax actuator has relatively simple binary on/off operation to activate the heater and is low in cost.

Prior to rupture (FIG.1), the rupture diaphragm38seals the inlet32from the outlet34such that the fuel26aremains isolated in the system20. The actuator40is actuated to extend the plunger40awhen the system20is to be activated to release fuel such that the space vehicle22becomes operable for propulsion and/or orientation adjustment. Upon actuation, the plunger40aextends and breaches the rupture diaphragm38, as shown inFIG.2. Once ruptured, the inlet32and the outlet34become fluidly connected, thereby permitting fuel to flow through the isolation valve24to the remainder28of the system20for propulsion and/or orientation adjustment. In one further example, the isolation valve24can be reused by removing the breached rupture diaphragm38and replacing it with a new, non-breached rupture diaphragm38.

FIG.3illustrates an isolated view of an example of the rupture diaphragm38. The rupture diaphragm38includes a diaphragm section38aand a rim38b. The diaphragm section38ain this example is metallic and may be formed of titanium or aluminum alloy. In this regard, the rupture diaphragm38is generally rigid, although it could alternatively be flexible as long as it can maintain isolation of the fuel26a.

In this example, the diaphragm section38ais partially spherical and convex (toward the plunger40a). Such a geometry permits the diaphragm section38ato be relatively close to the plunger40a, thereby reducing the required stroke length for breach. If the design envelope and stroke length allow, the diaphragm section38amay alternatively have a conical, pyramidal, or other geometry and may be concave or even planar.

In the illustrated example, the surface of the diaphragm section38ahas at least one score line38c. The score line38cis a groove in the surface that serves to weaken the diaphragm section38ain order to facilitate breaching by the plunger40a. The rim38bpermits the diaphragm38to be secured in a leak-free manner in the valve body30of the isolation valve24. For instance, as shown inFIG.1, the diaphragm38is integrated into the valve body30(i.e., is integral with) via the rim38bbeing welded to a flange32aof the inlet32. Additionally or alternatively, a portion of or all of the diaphragm38is machined into the valve body30.

FIG.4illustrates another example isolation valve124. In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding elements. In this example, the isolation valve124is configured for flow testing. In this regard, in addition to the inlet32and the outlet34, the valve body30defines a test port46that opens into the flow passage36and is fluidly connected with the outlet34but not the inlet32(at least prior to breach of the rupture diaphragm38). The test port46may be adapted with a desired form of connector for attaching various testing equipment. The outlet34contains a filter48and a venturi50. The filter48serves to facilitate removal of impurities in a test fluid, and the venturi aids in water hammer reduction.

FIG.5illustrates another example isolation valve224. In this example, the isolation valve224includes at least one knife edge52adjacent the rupture diaphragm38. The knife edge52is located on an opposite side of the rupture diaphragm38from the plunger140aof the actuator40. The plunger140a, when extended, deflects the diaphragm section38atoward the knife edge52. Upon impact between the knife edge52and the diaphragm section38a, the knife edge52breaches the diaphragm section38a. This breach may occur by cutting, piercing, tearing, or other manner that is sufficient to rupture the rupture diaphragm38such that the inlet32and the outlet34become fluidly connected, thereby permitting fuel to flow through the isolation valve224for propulsion and/or orientation adjustment.