PNEUMATIC VALVE POSITIONER WITH FEEDBACK CONTROLLED FLOW BOOSTER

Abstract

A pneumatically controlled flow booster includes a booster valve plug position sensor that enables control of the flow booster in a feedback loop, for example by a pneumatic valve positioner, thereby providing accurate, high speed, high flow control of both small and large actuator adjustments. Embodiments can accurately control a surge suppression valve over extended valve adjustment ranges and can fully open a surge suppression valve during a trip. The flow booster valve can include a spool and sleeve valve and/or a poppet valve. Embodiments provide bimodal flow boosting, whereby the output flow is less dependent on the valve plug position in a first position range, and more strongly dependent on the valve plug position in a second range.

Claims

1. A flow booster valve comprising: a first pneumatic control inlet configured to receive a first pneumatic control gas having a first pneumatic control pressure; a booster valve plug having a variable position within the flow booster valve, wherein a first longitudinal force is applied to the booster valve plug that is proportional to the first pneumatic control pressure; a first flow inlet in gas communication with a first flow outlet, a first gas flow from the first flow inlet to the first flow outlet being variable according to the position of the booster valve plug within the flow booster valve; and a valve plug position sensor configured to provide a sensor output that is indicative of the position of the booster valve plug within the booster valve.

2. The flow booster valve of claim 1, wherein a plug range over which the position of the booster valve plug is variable within the flow booster valve comprises a first position subrange and a second position subrange, and wherein the first primary gas flow is more strongly dependent on the position of the booster valve plug when the booster valve plug is within the second position subrange as compared to when the booster valve plug is within the first position subrange.

3. The flow booster valve of claim 2, wherein the first primary gas flow is variable according to a non-linear dependence on the position of the booster valve plug when the booster valve plug is in the first position subrange.

4. The flow booster valve of claim 1, wherein the flow booster valve does not include any electrically operated components.

5. The flow booster valve of claim 1, wherein the sensor output of the valve plug position sensor is mechanical.

6. The flow booster valve of claim 1, wherein the sensor output of the valve plug position sensor is one of electrical and pneumatic.

7. The flow booster valve of claim 1, wherein the flow booster valve further comprises a valve plug return spring configured to apply a return force to the booster valve plug in opposition to the first longitudinal force.

8. The flow booster valve of claim 1, wherein the flow booster valve further comprises a second pneumatic control inlet configured to receive input of a second pneumatic control gas having a second pneumatic control pressure, a second longitudinal force that is proportional to the second pneumatic control pressure being applied to the booster valve plug, the second longitudinal force being in opposition to the first longitudinal force.

9. The flow booster valve of claim 1, wherein the flow booster valve comprises a second flow inlet in gas communication with a second flow outlet, a second gas flow from the second flow inlet to the second flow outlet being variable according to the position of the booster valve plug within the flow booster valve.

10. The flow booster of claim 8, wherein a dependence of the first gas flow on the position of the booster valve plug and a dependence of the second gas flow on the position of the booster valve plug are substantially equal and opposite.

11. The flow booster valve of claim 1, wherein the flow booster valve comprises a spool and sleeve valve.

12. The flow booster valve of claim 1, wherein the flow booster valve comprises a poppet valve.

13. The flow booster valve of claim 1, further comprising a gas vent, wherein when the booster valve plug is in a first position the gas vent is in gas communication with the first flow outlet while the first flow inlet is blocked, and when the booster valve plug is in a second position the gas vent is blocked while the first flow inlet is in gas communication with the first flow outlet.

14. The flow booster valve of claim 1, further comprising a valve position controller configured to receive the sensor output provided by the valve plug position sensor, the valve position controller being further configured to supply the first pneumatic control gas to the first pneumatic control input.

15. The flow booster valve of claim 11, wherein the flow booster valve further comprises a supply gas outlet in gas communication with a gas supply inlet of the valve position controller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1A is a block diagram illustrating direct control of a process valve by a system controller according to the prior art;

[0046] FIG. 1B is a block diagram illustrating one-way pneumatic control of a process valve by a valve positioner according to the prior art;

[0047] FIG. 1C is a block diagram illustrating two-way pneumatic control of a process valve by a valve positioner according to the prior art;

[0048] FIG. 1D is a block diagram of a valve positioner that implements both inner and outer feedback loops according to the prior art;

[0049] FIG. 1E is a block diagram illustrating direct control of a surge suppression valve by a system controller according to the prior art;

[0050] FIG. 1F is a block diagram illustrating control of a surge suppression valve by a valve positioner according to the prior art;

[0051] FIG. 1G is a block diagram illustrating control of a surge suppression valve by a valve positioner and flow boosters according to the prior art;

[0052] FIG. 2A is a cross sectional illustration of a JetFlow booster valve according to an embodiment of the present invention;

[0053] FIG. 2B is a block diagram illustrating implementation of the JetFlow booster of FIG. 2A to control a surge suppression valve;

[0054] FIG. 3 is a block diagram that illustrates three control loops that are implemented by a Logix 3800 valve positioner in combination with a JetFlow booster in an embodiment of the present invention;

[0055] FIG. 4A is a graph of a bimodal output flow dependence upon JetFlow valve plug position in an embodiment of the present invention;

[0056] FIG. 4B is a cross sectional illustration similar to FIG. 2A of a JetFlow booster valve of the present invention that is configured to provide bimodal output flow as illustrated in FIG. 4A;

[0057] FIG. 5A is an isometric view, drawn to scale, of a spool and sleeve JetFlow booster embodiment of the of the present invention coupled to a Logix 3800 valve positioner;

[0058] FIG. 5B is a partially exploded perspective view from below, drawn to scale, of the valve positioner and JetFlow booster of FIG. 5A;

[0059] FIG. 5C is a top view, drawn to scale, of a disassembled spool and sleeve sleeve of the JetFlow booster of FIG. 5B

[0060] FIG. 6A is an isometric view drawn to scale of a poppet valve JetFlow booster embodiment of the present invention coupled to a Logix 3800 valve positioner;

[0061] FIG. 6B is a left side view drawn to scale of the JetFlow booster and Logix 3800 valve positioner of FIG. 6A;

[0062] FIG. 6C is an interior perspective view drawn to scale of the JetFlow booster of FIGS. 6A and 6B, wherein the sleeve elements and the control air element of the JetFlow booster have been removed to reveal a central shaft thereof, three of the sleeve elements and the control air element being separately illustrated with inner structure thereof indicated by dashed lines;

[0063] FIG. 6D is a perspective view drawn to scale of the central shaft of the embodiment of FIG. 6C separated from the support frame so that the sensor arm thereof is visible; and

[0064] FIG. 6E is a perspective view drawn to scale of the embodiment of FIG. 6A, where that the Logix 3800 has been lifted above the JetFlow booster so that a sensor interconnection therebetween is visible.

DETAILED DESCRIPTION

[0065] The present invention is an apparatus and method for pneumatically controlling the position of a valve actuator. The disclosed apparatus and method can provide rapid, accurate, high speed control for both small and large actuator adjustments, while also being simple and reliable in design and easy to tune and adapt for control of a valve system.

[0066] With reference to FIGS. 2A and 2B, the disclosed invention is a novel flow booster 200, referred to herein as a “JefFlow” booster, in which a booster valve plug 202 can be controlled by the gas output of a pneumatic valve positioner 110 such as a Logix 3800. The JetFlow booster valve 200 accepts a relatively high flow pneumatic input 206, and is able to provide a high flow output 208 that is proportional in pressure and flow to a relatively small pneumatic control input 210 supplied by the valve positioner 110. In the embodiment of FIG. 2B, the JetFlow booster valve 200 further includes an air supply output 212 that provides input air 114 for the valve positioner 110.

[0067] The JetFlow booster valve 200 of the present invention further includes a booster valve plug sensor 204 that can provide feedback to the valve positioner 110 indicating the physical position of the booster valve plug 202 within the JetFlow booster valve 200. In the illustrated embodiment, the booster valve plug sensor 204 is a mechanical sensor that links with the feedback shaft 126 of the Logix 3800 valve controller. The valve positioner 110 is thereby able to implement an additional feedback loop that controls the positioning of the booster valve plug 202 within the JetFlow booster valve 200, such that the JetFlow booster valve 200 acts as a feedback-controlled extension of the valve positioner 110. As a result, the valve positioner 110 and JetFlow booster valve 200, in combination, function as a high flow capacity valve positioner that can accurately implement rapid valve adjustments with both small and large adjustment amplitudes with little or no overshoot, and without requiring complex electronics such as stepper motors. In consequence, the disclosed apparatus is more reliable and simpler to tune than previous solutions. Embodiments implemented to control surge suppression valves are able to compensate for larger fluctuations in process flow as compared to previous approaches, thereby providing a more effective mechanism for preventing surge trip conditions.

[0068] In embodiments, all interactions between the the JetFlow booster valve 200 and the associated valve positioner 110 are pneumatic and/or mechanical, such that the JetFlow booster 200 valve does not require an independent power source, and is thereby an intrinsically nonincendive, explosion proof, and/or safety compliant system, for example per the NFPA and NEC or equivalent internal standards. In some embodiments, the valve positioner 110 is powered by a control signal such as a 4-20 mA signal, and does not require a separate power supply, which simplifies compliance with incendive, explosion, and safety compliant standards.

[0069] As an example, with reference to FIG. 3, the disclosed JetFlow booster can be controlled by a Logix 3800 valve positioner 110 whereby the JetFlow booster is implemented in a third, nested, “intermediate” control loop 304. In exemplary embodiments, the outer loop 300 of the Logix 3800 includes an outer loop controller 302 that receives a required valve position command from a system controller 100 to adjust the valve actuator 108 of a surge suppression valve 102 to a required actuator position. The outer loop controller 302 consults a calibrated relationship table and converts this request into a required change to the position of the JetFlow booster valve plug 202. This requirement is forwarded to the intermediate loop controller 306.

[0070] The intermediate loop controller 306 refers to a calibrated relationship table and converts the required position change of the JetFlow booster valve plug 202 into a required position change of the inner loop poppet valve(s) 132. This requirement is forwarded to the inner loop controller 310 for execution by the inner loop 308. Finally, the inner loop controller 310 refers to a calibrated relationship table and converts the required change of the poppet valve(s) 132 into a required change in the electrical energy that is applied to the poppet valve solenoid controller(s).

[0071] The inner loop controller 310 then applies the change to the poppet valve controllers, and makes any required corrections according to feedback received from poppet valve position sensors 134. Further commands are sent by the intermediate loop controller 306 to the inner loop controller 310 as needed, according to feedback provided to the intermediate loop controller 306 by the JetFlow valve plug sensor 204. And further commands are sent to the intermediate loop controller 306 by the outer loop controller 302 according to feedback provided to the outer loop controller 302 by the surge valve actuator position sensor 112.

[0072] With reference to FIG. 4A, in embodiments the JetFlow booster valve 200 is bi-modal, in that the flow through the booster valve 200 is divided into two position ranges 400, 402 of the booster valve plug 202. Within the first position range 400 of the valve plug 202, the gas flow through the JetFlow booster valve 200 is weakly dependent upon the position of the booster valve plug 202. This range of operation 400 is suitable for making relatively fine adjustments to the process valve actuator 108. Over the second position range 402 of the booster valve plug 202, the gas flow through the JetFlow booster valve 200 is more strongly dependent upon the position of the booster valve plug 202. This range of operation 402 is suitable for making relatively larger adjustments to the process valve actuator 108, and/or for fully opening the process valve 102 during a surge trip. FIG. 4B illustrates a spool and sleeve valve 200 similar to the valve of FIG. 2A, but wherein the JetFlow booster valve plug 202 has two diameter regions 404, 406, corresponding to the two position ranges 400, 402, of FIG. 4A.

[0073] In some embodiments the JetFlow booster valve 200 has sufficient flow capacity to fully open the surge suppression valve 100 during a surge trip event. In other embodiments, as illustrated in FIG. 2B, a venting relay system 144, 146 is implemented that blocks the pneumatic output 208 of the JetFlow booster valve 200 and vents the pneumatic input of the surge control valve actuator 108 in the event of a surge trip, thereby allowing the surge control valve actuator spring 118 to open the surge control valve 102 at maximum speed.

[0074] In the embodiment of FIG. 2B, the JetFlow booster valve plug position sensor 204 provides mechanical feedback to the valve positioner 110. In similar embodiments, the JetFlow booster valve plug position sensor 204 is magnetic, and provides electronic feedback to the valve positioner 110. In embodiments, the JetFlow booster valve 200 is a spool and sleeve valve or a poppet valve.

[0075] FIG. 5A is a perspective view from above of an embodiment of the present invention in which the JetFlow booster valve 200 is a spool and sleeve valve that is directly mounted to a Logix 3800 valve positioner 110. In the illustrated embodiment, the JetFlow booster valve 200 has two high flow air outlets 208a, 208b. The embodiment further includes an air outlet 212 that is directed through a regulator 500 to provide a lower flow at a regulated pressure to the air inlet 114 of the Logix 3800 110. Also visible in the figure are pressure gages 502 that are included with the Logix 3800 110. Output pneumatic control air from the Logix 3800 110 is directed to a pneumatic control input 210 at a proximal end of the JetFlow booster valve 200.

[0076] FIG. 5B is a perspective view from below of the embodiment of FIG. 5A where the sleeve 504 of the JetFlow booster valve 200 has been removed to expose the spool assembly 506 of the valve, which includes a spool 508 and a surrounding spool envelope 510. During operation, the spool envelope 510 remains fixed to the sleeve 504, and the spool 508 moves laterally within the envelope 510. A high flow input, 206 is visible in the figure, as well as two additional ports, 506a, 506b that serve as vent openings of the Jetflow booster valve 200. A spool return spring 118 is also visible at a distal end of the JetFlow booster valve 200. The JetFlow valve plug position “sensor” in the illustrated embodiment is a lever arm 204 having a proximal end fixed to a feedback shaft 126 of the Logix 3800 valve positioner 110, and a distal end coupled to the spool 508 of the JetFlow booster valve 200. As the spool 508 is translated within the spool sleeve envelope 510, the distal end of the lever arm 204 converts the lateral motion of the spool 508 into rotation of the feedback shaft 126 of the Logix 3800, thereby providing feedback to the Logix 3800 as to the position of the JetFlow spool 508. The Logix 3800 110 also receives feedback from the surge suppression valve actuator 108 via electronic signals received from a remote sensor 112 coupled to the surge suppression valve actuator 108.

[0077] FIG. 5C is a top view of the embodiment of FIG. 5B in which the spool 508 has been removed from the spool sleeve envelope 510. It can be seen in the figure that the spool 508 includes a pair of cylindrical pistons 202 mounted on a central shaft 512 that function as the valve plugs 202 of the JetFlow booster valve 200. When the JetFlow booster valve 200 is fully assembled, the spool sleeve envelope 510 is fixed to the sleeve 504, and is positioned so that openings 514, 516 provided in the spool sleeve envelope 510 overlap and effectively define the shapes of the high flow inlets 206 and outlets 208 of the booster valve 200. In the illustrated embodiment, these sleeve openings include central, large regions 514 that are substantially rectangular, and that control the relationship between the output flow and the positions of the spool pistons 202 when the spool 508 is in the second position range 402, as discussed above in reference to FIG. 4A. These central regions 514 are flanked by small notch regions 516 that control the relationship between the output flow and the position of the spool 508 when the spool 508 is in the first position range 400. Unlike the linear relationship that is illustrated in FIG. 4A, the “notch” shape of these small opening regions 516 results in a non-linear relationship between spool position and output flow when the spool 508 is in the first position range. Nevertheless, a much lower flow “boost” is provided in the first position range than in the second position region 402.

[0078] FIG. 6A is a right perspective view of an embodiment in which a Logix 3800 110 is combined with a poppet valve embodiment 630 of the JetFlow booster. In the illustrated embodiment, the poppet JetFlow booster 630 is divided into two substantially symmetric halves, each of which includes a supply sleeve element 600, an end sleeve element 602, and a vent sleeve element 604. In addition, a central control air element 644 is included. All of the sleeve elements 600, 602, 604, 644 are fitted into a common support frame 632.

[0079] FIG. 6B is a left side view of the embodiment of FIG. 6A. In the figure, it can be seen that the support frame 632 is penetrated by four large openings, which include two supply inlets 608 and two exhaust outlets 610. In addition, vents 606 are provided that connect with the vent sleeve elements 604. The supply inlets 608 can be connected, for example, to a high-volume gas supply 152, while the exhaust outlets could be connected, for example, to the two opposing gas inlets of a piston-driven valve actuator 108 that is pressure driven in both directions.

[0080] FIG. 6C is an interior perspective view of the JetFlow booster 630 of FIGS. 6A and 6B, where the sleeve elements 600, 602, 604, 644 have been removed to reveal a central shaft 612 that is supported by opposing springs 616 at both ends and supported by a central diaphragm 618. The three sleeve elements 600, 602, 604 from the right half of the support frame 632 as well as the control air element 638 are shown separately, with arrows and dashed lines indicating their locations when assembled with the support frame 632. Dashed lines shown within the sleeve elements indicate their internal structure. In particular, the control air input 638 can be seen in the figure on the control air sleeve element 644.

[0081] It can be seen in the figure that the springs 616 are supported by coaxial protrusions 650 provided within the end sleeve elements 602, and that the central shaft 612 further includes a pair of opposing poppets 614 and also a pair of vent plugs 620. The poppets 614 nest within poppet seats 652 provided in the supply sleeve elements 600, and the vent plugs 620 nest within central passages 654 of the vent sleeve elements 604, and thereby open and close the vents 636 as the central shaft is laterally shifted by the control air.

[0082] Control air applied to the control air inlet 638 of the control air element 644 applies a variable pressure to the diaphragm 618 and causes the central shaft 612 to shift laterally, thereby seating one of the poppets 614 against its poppet seat 652, while separating the other poppet 614 from its seat 652, thereby connecting one supply 610 to its exhaust outlet 608 while isolating the other poppet 614 from its exhaust outlet 608. At the same time, one of the vents 636 is opened while the other is closed.

[0083] The central shaft 612 with associated features is shown separated from the support frame 632 in FIG. 6D. It can be seen in the figure that a sensor arm 640 extends from the central shaft 612 in a manner similar to the valve plug sensor 204 of FIG. 5B, discussed above. As can be seen in FIG. 6C, a distal end of the sensor arm 640 is attached to the central shaft 612, and the sensor arm 640 extends from there into one of the exhaust outlets 610, where it terminates in a rotating element 642.

[0084] FIG. 6E is similar to FIG. 6A, except that the Logix 3800 110 has been lifted away from the JetFlow booster 630, so that the sensor interconnection between them can be seen. As is visible in the figure, the feedback shaft 126 of the Logix 3800 110 extend into a sensor passage 646 provided in the Jetflow booster 630, which intersects the exhaust outlet 610, so that the feedback shaft 126 can be connected to the rotating element 642 and thereby rotated as the central shaft is longitudinally shifted.

[0085] The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.

[0086] It will be understood by those of skill in the art that while frequent reference is made herein by way of example to control of a surge suppression valve, the present invention is not limited only to control of surge suppression valves, but is applicable in general to pneumatic gas valve position control where enhanced flow of pneumatic control gas is required.

[0087] Although the present application is shown in a limited number of forms, the scope of the invention is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof. The disclosure presented herein does not explicitly disclose all possible combinations of features that fall within the scope of the invention. The features disclosed herein for the various embodiments can generally be interchanged and combined into any combinations that are not self-contradictory without departing from the scope of the invention. In particular, the limitations presented in dependent claims below can be combined with their corresponding independent claims in any number and in any order without departing from the scope of this disclosure, unless the dependent claims are logically incompatible with each other.