Flow divider valve with relief management valve

A system includes a flow inlet conduit and a primary conduit that branches from the flow inlet conduit for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV) connects between the flow inlet conduit and a secondary conduit for delivering flow to a set of secondary nozzles. The EBV is connected to an equalization conduit (EC) to apportion flow from the flow inlet conduit to the secondary conduit. A pressure equalization solenoid (PES) is connected to the EC to selectively connect at least one of a servo supply pressure (PFA) conduit or return pressure (PDF) conduit into fluid communication with the EC. A relief management valve (RMV) is connected in the PDF conduit.

BACKGROUND

The present disclosure relates to flow splitting systems, and more particularly to flow divider valves such as for use in aerospace fuel systems.

2. Description of Related Art

Gas turbine burners can have at least two sets of fuel injection nozzles, e.g., primary nozzles and secondary nozzles. Valves are used to control the flow split between the primary and secondary nozzles. There are transitions from one flow split to another that need to be rate controlled to prevent disturbances, especially at low flow conditions. The better the time response when switching from one flow split to another without disturbances, the better the system can perform.

The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever present need for improved systems and methods for flow divider valves. This disclosure provides a solution for this need.

SUMMARY

A system includes a flow inlet conduit and a primary conduit that branches from the flow inlet conduit for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV) connects between the flow inlet conduit and a secondary conduit for delivering flow to a set of secondary nozzles. The EBV is connected to an equalization conduit (EC) to apportion flow from the flow inlet conduit to the secondary conduit. A pressure equalization solenoid (PES) is connected to the EC to selectively connect at least one of a servo supply pressure (PFA) conduit or return pressure (PDF) conduit into fluid communication with the EC. A relief management valve (RMV) is connected in the PDF conduit.

The RMV can include an orifice flow path, a secondary flow path, and a valve body that occludes the secondary flow path in first position and permits flow through the secondary flow path in a second position. The EBV can include a piston that divides flow between the EC and the flow inlet conduit to apportion flow from the flow inlet conduit to the secondary conduit based on a pressure differential between a flow meter pressure at the flow inlet conduit and a pressure in the EC. The PES can include a valve body positioned to selectively control the EBV by connecting at least one of the PFA conduit or the PDF conduit to switch the primary conduit and the secondary conduit between an equalized mode, where the primary and secondary conduits are at equal pressure, and an un-equalized mode, where the primary and secondary conduits are at unequal pressure.

The pressure in the EC can be at least one of a PFA or a PDF. An un-equalized enrichment valve (UEV) can connect between the flow inlet conduit and the secondary conduit. The UEV can be configured to pressurize the primary conduit higher than the secondary conduit in an un-equalized mode. The RMV can be configured to increase flow through PDF conduit as the difference between PFA and PDF is increased. The RMV can be configured to reduce flow through PDF conduit when the difference between PFA and PDF is lower, relative to the increased pressure difference. An EBV rate limiting high-pressure orifice can be connected in the PFA conduit.

In accordance with another aspect, a method includes selectively increasing or decreasing flow through the RMV by opening or closing a secondary flow path in parallel to an orifice flow path. The method can include increasing flow through the RMV when the difference between PFA and PDF pressure is greater than PDF and a RMV opening pressure. The method can include decreasing flow through the RMV when the difference between PFA and PDF pressure is less than a RMV opening pressure. The method can include selectively controlling the EBV with the PES.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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 embodiment of a system in accordance with the disclosure is shown inFIG.1and is designated generally by reference character100. Other embodiments of systems in accordance with the disclosure, or aspects thereof, are shown inFIGS.2-3and described below. The systems and methods described herein can be used to provide for variable rate limiting when transitioning between equalized and un-equalized modes without causing large fuel flow disturbances relative to traditional flow division systems that divide flow between a primary set of fuel nozzles and a secondary set of fuel nozzles. For rapid transients, rate limiting is reduced by a relief management valve which is set to open at higher pressures to reduce transition times. This allows for much faster flow split transitions relative to traditional systems, and/or reduce the resulting fuel flow disturbance at lower pressures. The systems and methods described herein can be retrofitted into many existing flow division systems.

As shown inFIG.1, a system100includes a flow inlet conduit102. A primary conduit104branches from the flow inlet conduit102for delivering flow to a set of primary nozzles. An equalization bypass valve (EBV)106connects between the flow inlet conduit102and a secondary conduit108for delivering flow to a set of secondary nozzles. The EBV106is connected to an equalization conduit (EC)122to be controlled by a pressure equalization solenoid (PES) to apportion flow, e.g. fluid flow, from the flow inlet conduit102to the secondary conduit108based on pressure differential between a flow meter pressure (PFDV) at the flow inlet conduit102and the servo pump supply pressure (PFA), e.g. PFDV plus PFA, and a pressure (PCE) in the EC122. The EBV106is a two position valve. The PCE is switched between the PFA pressure (which closes valve since PFA>PFDV) and a return pressure (PDF) which is lower than the sum of PFDV and PFA (which opens the valve).

With continued reference toFIG.1, the EBV106includes a piston120that separates between the EC122and the flow inlet conduit102to allow or restrict flow from the flow inlet conduit102to the secondary conduit108based on pressure differential between a flow meter pressure (PFDV) at the flow inlet conduit102and the servo pump supply pressure (PFA), and a pressure (PCE) in the EC122. The PCE is switched between the PFA pressure (which closes valve since PFA>PFDV) and PDF which is lower than the sum of PFDV and PFA (which opens the valve). To increase flow to secondary nozzles in an equalized mode, the EBV106opens by translating to the right. An EBV rate limiting high-pressure orifice112is connected in the PFA128conduit. Transitioning equalized to un-equalized modes is rate limited by the EBV Rate Limiting HP orifice112to minimize unacceptable flow disturbance during transition, particularly at low burn flows.

With continued reference toFIG.1, system100includes PES124connected to the EC122to switch the system100between an un-equalized and an equalized mode. The PES124includes a valve body126positioned to selectively PFA conduit128or a PDF conduit130into fluid communication with the EC122to switch the primary and secondary conduits104,108between an equalized mode (FIG.3), where the primary and secondary conduits104,108are at equal pressure, and an un-equalized mode (FIG.1), where the primary and secondary conduits104,108are at unequal pressure.

As shown inFIG.2, the rate of EBV106translation, as indicated schematically by the arrow on valve body120, in some instances, was controlled by a fixed orifice in the flow path from EC122to an outlet portion129of PDF conduit130. In embodiments of the present disclosure, the EBV rate of translation is limited by a relief management valve (RMV)118connected in the PDF conduit130to prevent unacceptable flow disturbance during transition. The RMV includes an orifice flow path136, secondary flow path132(the obliquely angled passages), and a valve body138that occludes (or partially occludes) the secondary flow path132in first (closed) position, shown inFIGS.1and3, and permits flow through the secondary flow path132in a second (open) position, shown inFIG.2. The valve body138is configured to open more flow into the PDF conduit130by way of the secondary flow path132at higher differentials between PFA and PDF in the transient to the equalized mode after the valve body126moves to the left. This allows both ‘slow’ and ‘fast’ EBV translations to be possible when switching from equalized to unequalized modes. In high-pressure scenarios, the RMV opens up secondary flow path132in parallel to orifice flow path136, when actuated open by PFA pressure in the PFA conduit128, and bypasses the rate limiting orifice in the orifice flow path136. This allows fast transitions at high pressure settings, while still maintaining slow transitions at low pressure settings

With continued reference toFIGS.2-3, the RMV118is configured to allow more flow through the PDF conduit130to outlet portion129by allowing flow through the secondary flow path132as the differential between PFA and PDF pressure rises (regardless of whether transitioning to equalized or unequalized mode). The RMV118is configured to reduce flow through the PDF conduit130to/from an outlet portion129by occluding secondary flow path132as the differential between PFA and PDF decreases. The RMV118provides additional capability to control the rate of EBV106, thereby allowing fast transitions at high pressure conditions, but still maintain slow transitions at lower pressure settings to minimize disturbances in the rest of the fuel system100.

As shown inFIG.2, movement of the valve body126to the left of the position shown inFIG.3places EC122and PDF conduit130in fluid communication with one another, actuating piston120to the right. The pressure in the EC122is at least one of PFA or PDF. An un-equalized enrichment valve (UEV)134connects between the flow inlet conduit102and the secondary conduit108. The UEV134is configured to pressurize the primary conduit104higher than the secondary conduit108in the un-equalized mode resulting in enriched flow to the primary nozzles, e.g. for starting and burner tonal control. In equalized mode, the pressure delivered to primary and secondary nozzles is the same and the flow split between the nozzles is a function of only the nozzle area ratio. When the EBV106is open, it opens a large flow path from flow inlet conduit102to the secondary conduit108. When EBV106is closed, the only path from flow inlet conduit102to the secondary conduit108is through the UEV134, so the UEV regulates to a high pressure from the primary conduit104to the secondary conduit108pressure.

With reference toFIGS.1-3, during a high acceleration from idle to high power, the RMV118initially limits how quickly the EBV106can open (e.g. translate to the right as oriented inFIGS.1-3). If the EBV106opens too slowly during the entire transient, too much flow is forced through the more restrictive primary circuit, resulting in a higher pressure spike in upstream components. The RMV118closes secondary flow path132at low pressure assuring that EBV106swept flow is restricted and rate limiting of the EBV106is sufficiently slow. As shown inFIG.2, the RMV118is actuated open (e.g. valve body138is moved to the right as oriented in the figures) if the differential between PFA and PDF pressure is greater than RMV118opening pressure. The RMV118therefore allows for control of EBV open rate based on the differential between PFA and PDF. A method for controlling flow through includes controlling flow through the RMV by opening a secondary flow path in parallel to an orifice flow path when the difference between PFA and PDF is greater than an RMV opening pressure.

The methods and systems of the present disclosure, as described above and shown in the drawings, provide for variable rate-controlled split transitions to minimize the disturbances relative to traditional flow division systems that divide flow between a primary set of fuel nozzles and a secondary set of fuel nozzles. For rapid transients, the RMV permits bypassing a fixed rate limiting to assure transient over-pressurization does not occur. This can allow for much faster flow split transitions relative to traditional systems, while still maintaining slow transitions at low power to reduce fuel flow disturbances. 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 scope of the subject disclosure.