Patent Application
20160376913
1. Field of the Invention
The present disclosure relates to valves, and more particularly to pressure control mechanisms for valves used in bleed systems such as those used in gas turbine engines.
2. Description of Related Art
A variety of devices require a substantially constant supply of pressurized fluid in order to function properly. For example, secondary aircraft systems such as environmental control or anti-ice systems often require an input supply of constant pressure gas. Sources of pressurized gas, for example, are present in the compressor of gas turbine engine. If the pressure in one of the sources, e.g. an intermediate-pressure (IP) bleed valve, is too low for the secondary aircraft system, high-pressure bleed fluid from a high-pressure (HP) bleed valve is utilized. To transition from the IP bleed fluid to the HP bleed fluid, a pressure control mechanism, e.g. an electromechanical interface such as a solenoid, is actuated to cause the HP bleed valve to open and the IP valve to close. Typically, the required HP fluid pressure for use in the secondary aircraft systems is lower than the maximum HP fluid pressure. However, pressure control mechanisms are generally designed to ensure the valve is closed whenever the HP fluid pressure is above the minimum required pressure, meaning that the solenoid is sized for maximum HP fluid pressure conditions, and in turn maximum temperature conditions.
Typically, this results in weight and packaging penalties due to the larger coils and spring forces required, even though the device may not be required to operate at higher pressures. Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for an improved pressure control mechanisms. The present disclosure provides a solution for this need.
A bleed valve system includes a flow path defined between a system inlet and a system outlet. A pressure control mechanism is defined in the flow path downstream from the system inlet to selectively block fluid flow in the flow path. A pressure limiter is defined in the flow path downstream from the system inlet and upstream from the pressure control mechanism to block the flow path when the pressure at the system inlet is greater than the pressure capacity of the pressure control mechanism.
The pressure control mechanism and the pressure limiter can each include respective biasing members. The biasing member of the pressure control mechanism can have a biasing force less than the biasing force of the biasing member of the pressure limiter. The respective biasing members of the pressure control mechanism and the pressure limiter can be springs. The pressure control mechanism can be a solenoid. The system can include a bleed valve in fluid communication with the system outlet downstream from the pressure control mechanism.
The pressure control mechanism can include a control pressure outlet in selective fluid communication with the flow path and a ball valve defined between the control pressure outlet and the flow path. In a closed position the ball valve can seal the flow path to block fluid flow from the system inlet to the system outlet while allowing fluid flow from the control pressure outlet to the system outlet. In an open position, the ball valve can allow fluid flow from the system inlet to the system outlet while blocking fluid flow from the control pressure outlet to the system outlet.
The pressure limiter can include a valve body defining an inlet chamber in fluid communication with the system inlet, an outlet chamber downstream from the inlet chamber, and a bleed orifice defined in the outlet chamber to hinder fluid buildup in the flow path downstream from the outlet chamber. A poppet is defined in the flow path between the inlet chamber and the outlet chamber. The poppet can seal against the valve body in a closed position to block fluid flow in the flow path between the inlet chamber and the outlet chamber. In an open position, the poppet can be separated from the valve body to allow fluid flow from the inlet chamber to the outlet chamber.
The valve body can include a spring chamber opposite of the inlet chamber. The spring chamber can include a spring having a seat. The seat can be operatively connected to a guide of the poppet. The seat of the spring can inhibit leakage from the flow path to the spring chamber when the poppet is in an open position. The valve body can be a first valve body and the outlet chamber can be in fluid communication with an inlet of a second valve body of the pressure limiter, e.g. a back-up valve body. The second valve body of the pressure limiter can be configured to close at a higher pressure than that of the first valve body. A spring of the second valve body can have a higher spring force than a spring of the first valve body.
A pressure limiter includes a valve body defining an inlet chamber, an outlet chamber in selective fluid communication with a flow path defined from the inlet chamber to the outlet chamber, and a bleed orifice defined in the outlet chamber to hinder fluid buildup in the outlet chamber. A poppet is defined in the flow path between the inlet chamber and the outlet chamber. The poppet seals against the valve body in a closed position to block fluid flow in the flow path between the inlet chamber and the outlet chamber to prevent fluid flow from reaching a downstream pressure control mechanism when the pressure of the fluid entering the inlet chamber exceeds a maximum threshold. When the pressure of the fluid entering the inlet chamber is below the maximum threshold the poppet is separated from the valve body in an open position to allow fluid flow from the inlet chamber to the outlet chamber.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of a bleed valve system constructed in accordance with the disclosure is shown in
As shown in
With continued reference to
As shown in
With reference now to
Valve body 120 includes a spring chamber 130 opposite of inlet chamber 122. Spring chamber 130 includes biasing member 114, for example, a spring, having a seat 132. Seat 132 is operatively connected to a guide 134 of poppet 128. The maximum open stroke of poppet 128 is set by spring seat 132 bottoming against valve body 120. Seat 132 of spring 114 inhibits leakage from flow path 102 to spring chamber 130 when poppet 128 is in an open position. Preload of spring 114 defines the point at which poppet 128 begins to close. Those skilled in the art will readily appreciate that in order to minimize the band between open and closed positions, the spring rate is minimized.
With continued reference to
In an open position, as shown in
With continued reference to
The methods and systems of the present disclosure, as described above and shown in the drawings, provide light weight, compact and controllable bleed valve systems that can operate at high temperatures and pressures with reduced energy consumption and heat generation. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure.
