DESC:FIELD
The present disclosure relates generally to the field of a pressure control valve. In particular, the present disclosure relates to a mechanical control module for a pressure control valve.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
A control valve is used to control fluid flow by varying the size of flow passage as directed by a signal from a controller. This enables direct control of the flow rate and consequential control of process quantities such as pressure, temperature, and level of fluid.
Control valves are widely used in process industries; therefore, they have to be extremely sensitive and responsive to change in fluid pressure for attaining better control of pressure within pipelines. Failure of these valves to respond to change in pressure may cause damage to the process and the product manufactured under such processes. An approach to avoid aforesaid problem is providing theses control valves with a control module for efficient operation of the control valves.
A conventional control module for a control valve is a combination of an electrical torque motor and a pneumatic pilot valve. In such control module, pressure to be controlled within the pipelines is sensed by a pressure transmitter and is communicated to a Proportional-Integral-Derivative (PID)/ Distributed Control System (DCS) unit. Depending on the requirement, the PID unit sends required current to the torque motor. When the input current increases, an L-spring of the torque motor pivots and an armature receives a counter-clockwise torque. The counter-clockwise torque on the armature pushes a counterweight to compress a compression spring and increases the clearance between a nozzle and a flapper which in turn causes nozzle back pressure to decrease. The decreased back pressure in turn increases the pressure within the control valve that stretches a diaphragm of the actuator of the control valve there by controlling the pressure.
However, the conventional electro-pneumatic control modules require constant source of electricity and cannot work under hazardous environment. Further, these modules are complicated in construction or working and are expensive to install and maintain.
Therefore, there is felt a need for a control module that overcomes the drawbacks of prior art.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a mechanical control module for a pressure control valve.
Yet another object of the present disclosure is to provide a mechanical control module for a pressure control valve that is simple in construction.
Still another object of the present disclosure is to provide a mechanical control module for a pressure control valve that is easy to install.
Another object of the present disclosure is to provide a mechanical control module for a pressure control valve which is suitable for applications in hazardous environments.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a mechanical control module for a pressure control valve. The mechanical control module comprises a bellow configured to sense an outlet pressure; a nozzle configured with a flapper, the flapper configured to regulate the opening and closing of the nozzle; a counterweight mechanically engaged with the flapper; and a plunger configured to transfer the motion of the bellow to the counterweight. The bellow is configured to sense an increase in outlet valve pressure, a clockwise torque is generated by means of the plunger around a pivot. The generated torque is transmitted to the counterweight which pushes the flapper of the nozzle and regulate the amount of closing of the nozzle.
In an embodiment, the bellow senses an increase in the valve outlet pressure and activates the counterweight .i.e. the counterweight pushes the flapper and reduces the clearance between the flapper and the nozzle. Thus, there is increase in nozzle back pressure, consequently the exhaust valve of the pilot valve moves to the left. The output pressure decreases and the actuator diaphragm is relaxed or moves downward.
Further, when the bellow senses a decrease in the valve outlet pressure, the counterweight pulls the flapper and increases the clearance between the flapper and the nozzle. This causes the nozzle back pressure to decrease. Consequently, the exhaust valve of the pilot valve moves to the right and the supply valve opens the orifice. The output pressure increases and thereby, the actuator diaphragm moves upward.
Advantageously, it eliminates the requirements of the electrical torque motor and thus, proportional-Integral-Derivative (PID) or Distributed Control System (DCS) unit. Therefore, the pressure control valve operates efficiently in a hazardous environment by means of the mechanical control module.
Further, the control module comprises an exhaust valve provided on a pilot valve, an actuator diaphragm configured with an actuator spindle, and a feedback spring configured to compress or extend with the oscillation of a feedback lever. Also, a transmission lever and a span adjustment lever is provided to maintain stability at a balance position generated by the input feedback pressure. Furthermore, a plurality of setting spring is provided, wherein the setting spring is a set pressure coarse adjustment spring and a set pressure fine adjustment spring.
Typically, the mechanical control module includes a gain suppression spring, configured to direct the feedback of the motion of the exhaust valve to the counterweight, which enhances the stability of the loop.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A mechanical control module for pressure control valve of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a general arrangement of a control valve with a conventional control module;
Figure 2 illustrates an arrangement of a control valve with a mechanical control module for a pressure control valve in accordance with the present disclosure; and
Figure 3 illustrates a block diagram depicting the working of a control valve with a mechanical control module of Figure 2.
LIST OF REFERENCE NUMERALS
1 Automatic/manual change-over screw
2 Sensitivity adjusting screw
3 Built-in bleed restriction
4 Adjusts gain
5 Supply valve
6 Exhaust valve
7 Flapper
8 Feedback lever
9 Pilot Valve Diaphragm
10 Nozzle
11 Gain suppression spring
12 Counterweight
13 Pilot valve
14 Stopper screw
15 Diaphragm operated actuator
16 Span adjusting screw
17 Lock screw
18 Transmission pin
19 Span adjusting lever shaft
20 Span adjusting lever
21 Feedback spring
22 Input current terminal
23 Armature
24 Torque motor
25 L spring
26 Zero adjusting screw
27 Zero adjusting spring
50 Actuator Diaphragm
52 Actuator spindle

101 Automatic/manual change-over screw
102 Sensitivity adjusting screw
103 Built-in bleed restriction
104 Adjusts gain
105 Supply valve
106 Exhaust valve
107 Flapper
108 Feedback lever
109 Pilot Valve Diaphragm
110 Nozzle
111 Gain suppression spring
112 Counterweight
113 Pilot valve
114 Stopper screw
115 Diaphragm operated actuator
116 Span adjusting screw
117 Lock screw
118 Transmission pin
119 Span adjusting lever shaft
120 Span adjusting lever
121 Feedback spring
122 Set pressure coarse adjustment spring
123 Pressure sensing bellow
124 Control valve outlet feedback pressure
125 L spring
126 Set pressure fine adjustment spring
127 Plunger
150 Actuator Diaphragm
152 Actuator spindle
200 Mechanical control module
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
Figure 1 illustrates a conventional control module for a pressure control valve. The conventional pressure control module is a combination of an electrical torque motor 24 and a pneumatic pivot valve 13. The pressure to be controlled within the pipelines is sensed by a pressure transmitter and is communicated to a PID/DCS unit, where PID stands for ‘proportional-integral-derivative’ and DCS stands for ‘distributed control system’. Depending on the pressure requirement, the PID unit sends required current (4mA to 20mA) to the torque motor 24. When the input current increases, an L spring 25 of the torque motor 24 pivots and an armature 23 receives a counter-clockwise torque for the torque motor 24. The counter-clockwise torque on the armature pushes a counterweight 12 to compress the compression spring 11. This causes clearance between a nozzle 10 and a flapper 7 to increase which in turn causes the nozzle back pressure to decrease. Consequently, an exhaust valve 6 of a pilot valve 13 moves in direction opposite to the movement of the counterweight 12. The output pressure increases and stretches the diaphragm 9 in the pilot valve 13. The motion of the spindle acts on a feedback spring 21 through a feedback lever 8, a transmission lever and a span adjustment lever 20 to rest at the balance position generated by the input current. The compensating spring 11 is for direct feedback of the motion of the exhaust valve 6 to the counterweight 12 and increases the stability of the loop. The zero point can be adjusted by changing the tension on a zero adjustment spring 27.
However, this type of conventional pressure control module requires continuous supply of electricity and external signal cable to function, which can limit its use in a hazardous environment.
Further these control valves requires the additional PID control system and the transmitters which incurs an additional installation cost. Furthermore, control calves with conventional pressure control module have maximum pressure limitations and hence limited in its usage.
The preferred embodiment of the present invention will now be described with reference to Figure 2 and Figure 3. The present disclosure illustrates a mechanical control module 200 which is used with a pressure control valve.
The mechanical control module for a pressure control valve of the present disclosure comprises a bellow 123, a nozzle configured with a flapper 107, a counterweight 112 mechanically engaged with the flapper 107 and a plunger 127 configured to transfer the motion of the bellow 123 to the counterweight 112. The bellow 123 acts as a pressure sensing element, which is configured to sense a valve outlet pressure and the flapper is configured to regulate the opening and closing of the nozzle 110.
According to an embodiment, when the bellow 123 senses an increase in valve outlet pressure, the plunger attached to the bellow 123 starts angular movement about a pivot. This causes the generation of a clockwise torque around the pivot. The generated torque is thus transmitted to the counterweight 112 which pushes the flapper 107 of the nozzle 110 and regulates the closing of the nozzle 110. An L-spring 125 is working as the pivot.
Further, the mechanical control module 200 comprises an exhaust valve 106 provided on a pilot valve 113, an actuator diaphragm 150 configured with an actuator spindle 152, and a feedback spring 121 configured to compress or extend with the oscillation of a feedback lever 108.
The outlet valve pressure is varied by using two settings spring. The first being a coarse setting, which is adjusted by changing the compression in a set pressure coarse adjustment spring 122 and the second being a fine setting which is adjusted by changing tension in a set pressure fine adjustment spring 126.
According to another embodiment, when the bellow 123 detects an increase in the valve outlet pressure in case of a normally closed valve, the plunger attached to the bellow 123 pushes the counterweight 112 away from a gain suppression spring 111 which in-turn pushes the flapper 107. This causes the clearance between the nozzle 110 and the flapper 107 to decrease, and the nozzle back pressure to increase. Consequently, the exhaust valve 106 of the pilot valve 113 moves in a direction opposite to the movement of the counterweight and the supply valve 105 closes the orifice. The output pressure decreases and the actuator diaphragm 150 is relaxed or moves downward.
The downward motion of the actuator diaphragm 150 activates the actuator spindle 152, wherein the motion of the actuator spindle acts on the feedback spring 121 through the feedback lever 108. A transmission lever and a span adjustment lever 120 is provided to maintain stability at a balance position, generated by the input feedback pressure.
Thus, if the inlet pressure of the control valve is increased, then the set pressure is obtained by reducing the opening area of the valve. The suppression spring 111 provides direct feedback of the motion of the exhaust valve 106 to the counterweight 112 to increase the stability of the loop.
Further, when the bellow 123 senses a decrease in the valve outlet pressure, the counterweight 112 pulls the flapper 107 and increases the clearance between the flapper 107 and the nozzle 110. This causes the nozzle back pressure to decrease. Consequently, the exhaust valve 106 of the pilot valve 113 moves to the right and the supply valve 105 opens the orifice. The output pressure increases and thereby, the actuator diaphragm 150 moves upward.
Advantageously, the arrangement of the mechanical control module with the pressure control valve completely eliminates the requirements of the conventional torque motor which works on the 4-20 mA current. And therefore, the mechanical control module for pressure control valve is suitable to use in the hazardous environments or where continuous access to electricity is difficult. This arrangement of the mechanical control module 200 also saves the additional installation cost of the PID control system and the transmitters.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a mechanical control module for pressure control valve, that:
• requires no external signal cable or an electrical torque motor, thereby makes it suitable for application in a hazardous environment;
• requires no PID control system and transmitters, and hence it reduces the additional installation costs;
• can be used with any actuators as the present system does not have any limitations for maximum pressure;
• consumes less air; and
• provides higher accuracy with respect to a conventional pressure control valve system.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A mechanical control module (200) for a pressure control valve, said mechanical control module comprises:
• a bellow (123) configured to sense a valve outlet pressure;
• a nozzle (110) configured with a flapper (107), said flapper (107) configured to regulate the opening and closing of said nozzle (110);
• a counterweight (112) mechanically engaged with said flapper (107); and
• a plunger (127) configured to transfer the motion of said bellow (123) to said counterweight (112),
said bellow (123) configured to sense an increase in the valve outlet pressure and to generated a clockwise torque by means of said plunger (127) around a pivot, said torque being transmitted to said counterweight (112) that pushes said flapper (107) and regulates the closing of said nozzle (110).

2. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein, said mechanical control module comprises an exhaust valve (106) provided on a pilot valve (113), a actuator diaphragm (150) configured with an actuator spindle (152), and a feedback spring (121) configured to compress or extend with the oscillation of a feedback lever (108).

3. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein, when said bellow (123) senses an increase in pressure, said counterweight (112) pushes said flapper (107) and reduces a clearance between said flapper (107) and said nozzle (110), thereby it creates increase in nozzle back pressure, wherein said exhaust valve (106) of said pilot valve (113) moves to the left, the supply valve (105) closes the orifice, which decreases the output pressure and thereby, the actuator diaphragm (150) moves downward.

4. The mechanical control module (200) for a pressure control valve as claimed in claim 3, wherein the downward motion of said actuator diaphragm (150) activates said actuator spindle (152), wherein the motion of said actuator spindle (152) acts on said feedback spring (121) through said feedback lever (108).

5. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein said mechanical control module (200) comprises a transmission lever and a span adjustment lever (120) to provide stability at a balance position generated by the input feedback pressure.

6. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein said mechanical control module
(200) comprises a plurality of setting spring, said setting springs includes a set pressure coarse adjustment spring (122) and a set pressure fine adjustment spring (126).

7. The mechanical control module (200) for a pressure control valve as claimed in claim 6, wherein said set pressure fine adjustment spring (126) is configured for a fine setting of the valve outlet pressure by adjusting a tension in said set pressure fine adjustment spring (126).

8. The mechanical control module (200) for a pressure control valve as claimed in claim 2, wherein an L-spring (125) is working as said pivot.

9. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein said mechanical control module includes a gain suppression spring (111), configured to direct the feedback of the motion of said exhaust valve (106) to said counterweight (112), which enhances the stability of the loop.

10. The mechanical control module (200) for a pressure control valve as claimed in claim 1, wherein, when said bellow (123) senses a decrease in pressure, said counterweight (112) pulls said flapper (107) and increases a clearance between said flapper (107) and said nozzle (110), thereby it creates decrease in nozzle back pressure, wherein said exhaust valve (106) of said pilot valve (113) moves to the right, the supply valve (105) opens the orifice, which increases the output pressure and thereby, the actuator diaphragm (150) moves upward.

Dated this 23rd day of July, 2020

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant.