Passive modulating design for fast responding control valves for high pressure gas applications
A passive, modulating flow control valve including a poppet having a precisely designed and constant unbalanced area. A spring rate is selected to achieve the desired poppet travel over the desired range of differential pressure. Preferably, the spring preload is selected such that the poppet will remain fully open until a specified minimum differential pressure is reached. The unbalanced area and spring force allow the poppet to reposition proportional to the differential pressure throughout the design range of differential pressure. An array of radial holes in the poppet are used to define the trim characteristics. As the poppet is pushed closed by the differential pressure, few radial holes remain uncovered, which increases the flow resistance. The single modulating poppet includes flow and trim characteristics that respond directly to differential pressure acting on it to achieve tight control of the mass flow rate.
1 . A passive modulating flow control valve for maintaining a substantially constant mass flow rate over a fluid differential pressure design range across the valve, the valve comprising: a body assembly comprising a main body having a longitudinal bore, the body assembly having a flow inlet passageway in communication with the longitudinal bore and a flow outlet passageway in communication with the longitudinal bore; a poppet guide received within the longitudinal bore, the poppet guide having an axial guide bore; a poppet having an internal passage extending axially through the poppet, the poppet having an upstream portion and a downstream portion, the downstream portion having a plurality of radially-oriented flow passages, the poppet having a first outer diameter on the downstream portion and a second outer diameter on the upstream portion, the outer diameter of the upstream portion being larger than the outer diameter of the downstream portion, the transition from the downstream portion outer diameter to the upstream portion outer diameter occurring at a step, wherein at least a portion of the downstream portion of the poppet is received in the axial guide bore and allowed to move axially relative to the poppet guide; a spring received within the longitudinal bore, the spring providing a spring force on the poppet; wherein the valve is allowed to transition from a fully-open position to a closed position and positions in between based upon the fluid differential pressure acting on the poppet.
2 . The passive modulating flow control valve of claim 1 , wherein the plurality of radially-oriented flow passages includes radially-oriented flow passages spaced at different distances from a downstream end of the poppet.
3 . The passive modulating flow control valve of claim 1 , wherein in the fully closed position substantially all of the plurality of radially-oriented flow passages are within the poppet guide and covered.
4 . The passive modulating flow control valve of claim 1 , wherein the valve has a design range of differential pressure ranging between a high differential pressure and a low differential pressure, wherein at the high differential pressure the poppet is forced to the closed position and substantially all of the plurality of radially-oriented flow passages are within the poppet guide and covered, and wherein at the low differential pressure the poppet is forced to the open position and the plurality of radially-oriented flow passages are uncovered.
5 . The passive modulating flow control valve of claim 4 , wherein in the open position the plurality of radially-oriented flow passages are in fluid communication with the flow outlet passageway.
6 . A passive modulating flow control valve comprising:
a body assembly comprising a main body having a longitudinal bore, the body assembly having a flow inlet passageway in communication with the longitudinal bore and a flow outlet passageway in communication with the longitudinal bore;
a poppet guide received within the longitudinal bore, the poppet guide having an axial guide bore;
a poppet having an internal passage extending axially through the poppet, the poppet having an upstream portion and a downstream portion, the downstream portion having a plurality of radially-oriented flow passages, the poppet having a first outer diameter on the downstream portion and a second outer diameter on the upstream portion, the outer diameter of the upstream portion being larger than the outer diameter of the downstream portion, the transition from the downstream portion outer diameter to the upstream portion outer diameter occurring at a step,
wherein at least a portion of the downstream portion of the poppet is received in the axial guide bore and allowed to move axially relative to the poppet guide;
a push rod assembly abutting the downstream portion of the poppet;
a spring seat connected to the push rod assembly;
a spring guide screw engaging the body assembly;
a spring received within the longitudinal bore, the spring having a first end contacting the spring guide screw and a second end contacting the spring seat, the spring providing a spring force on the poppet.
7 . The passive modulating flow control valve of claim 6 , wherein the push rod assembly includes a flow passageway extending therethrough, the flow passageway in fluid communication with the internal flow passage of the poppet.
8 . The passive modulating flow control valve of claim 7 , wherein the push rod assembly includes a medial flange in contact with the longitudinal bore of the body assembly, and the medial flange includes a plurality of axial ports extending therethrough.
9 . The passive modulating flow control valve of claim 8 , further comprising an annular damping component received in an annular recess of the medial flange, the damping component contacting the longitudinal bore of the body assembly.
10 . The passive modulating flow control valve of claim 7 , wherein the flow passageway of the push rod assembly includes a reduced diameter portion at an upper end of the push rod assembly.
11 . The passive modulating flow control valve of claim 6 , wherein the plurality of radially-oriented flow passages are specifically spaced along a length of the downstream portion of the poppet.
12 . The passive modulating flow control valve of claim 6 , wherein in the fully closed position substantially all of the plurality of radially-oriented flow passages are within the poppet guide and covered.
13 . The passive modulating flow control valve of claim 6 , wherein the valve has a design range of differential pressure ranging between a high differential pressure and a low differential pressure, wherein at the high differential pressure the poppet is forced to the closed position and substantially all of the plurality of radially-oriented flow passages are within the poppet guide and covered, and wherein at the low differential pressure the poppet is forced to the open position and the plurality of radially-oriented flow passages are uncovered.
14 . The passive modulating flow control valve of claim 13 , wherein in the open position the plurality of radially-oriented flow passages are in fluid communication with the flow outlet passageway.
15 . A passive modulating flow control valve comprising:
a body assembly comprising a main body having a longitudinal bore, the body assembly having a flow inlet passageway in communication with the longitudinal bore and a flow outlet passageway in communication with the longitudinal bore;
a poppet guide received within the longitudinal bore, the poppet guide having an axial guide bore;
a poppet having an internal passage extending axially through the poppet, the poppet having an upstream portion and a downstream portion, the downstream portion having a plurality of radially-oriented flow passages, wherein the downstream portion of the poppet is received in the axial guide bore and allowed to move axially relative to the poppet guide;
a spring received within the longitudinal bore, the spring providing a spring force on the poppet;
wherein the valve is allowed to transition from a fully-open position to a closed position and positions in between based upon a fluid differential pressure acting on the poppet.
16 . The passive modulating flow control valve of claim 15 , wherein the poppet has a first outer diameter on the downstream portion and a second outer diameter on the upstream portion, the outer diameter of the upstream portion being larger than the outer diameter of the downstream portion.
17 . The passive modulating flow control valve of claim 15 , wherein the plurality of radially-oriented flow passages includes radially-oriented flow passages spaced at different distances from a downstream end of the poppet.
18 . The passive modulating flow control valve of claim 15 , wherein the valve has a design range of differential pressure ranging between a high differential pressure and a low differential pressure, wherein at the high differential pressure the poppet is forced to the closed position and substantially all of the plurality of radially-oriented flow passages are within the poppet guide and covered, and wherein at the low differential pressure the poppet is forced to the open position and the plurality of radially-oriented flow passages are uncovered.
19 . The passive modulating flow control valve of claim 15 , further comprising:
a push rod assembly abutting the downstream portion of the poppet;
a spring seat connected to the push rod assembly;
a spring guide screw engaging the body assembly,
wherein the spring has a first end contacting the spring guide screw and a second end contacting the spring seat.
20 . The passive modulating flow control valve of claim 19 , wherein the push rod assembly includes a flow passageway extending therethrough, the flow passageway in fluid communication with the internal flow passage of the poppet.
21 . The passive modulating flow control valve of claim 20 , wherein the push rod assembly includes a medial flange in contact with the longitudinal bore of the body assembly, and the medial flange includes a plurality of axial ports extending therethrough.
22 . The passive modulating flow control valve of claim 21 , further comprising an annular damping component received in an annular recess of the medial flange, the damping component contacting the longitudinal bore of the body assembly.
23 . The passive modulating flow control valve of claim 20 , wherein the flow passageway of the push rod assembly includes a reduced diameter portion at an upper end of the push rod assembly.