Claims:1. An apparatus (100) to compensate temperature of proportional valves for flow control, said apparatus comprising:
a pressure regulator (102) configured in the apparatus, the pressure regulator regulates flow of fluid to a desired quantity;
a proportional valve (104) coupled to said pressure regulator (102), and operates upon receipt of a set of signals, to allow dispensation of the fluid;
a controller (110) operatively coupled to the proportional valve, the controller coupled to a memory comprising a first storage unit (112-1) and a second storage unit (112-2), said memory storing instructions executable by the controller to:
generate the set of signals pertaining to pulse width modulation (PWM) count, the set of signals is received by the proportional valve; and
compute, from the generated set of signals, the temperature constant for the generated set of signals, wherein, based on the determination of the temperature constant of the generated set of signals, the controller is configured to operate the proportional valve to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide sufficient quantity of fluid supply.
2. The apparatus as claimed in claim 1, wherein the fluid is any or a combination of air and oxygen.
3. The apparatus as claimed in claim 1, wherein said pressure regulator (102) receives the fluid from said proportional valve (104).
4. The apparatus as claimed in claim 1, wherein the apparatus comprises a sensor (106) to measure the flow of the fluid.
5. The apparatus as claimed in claim 1, wherein the controller (110) configured to:
initialize an array to store analogue to digital converter (ADC) value which is read for the defined sampling duration, for every PWM count applied;
calculate the average ADC value after achieving the targeted flow value for the PWM count by discarding the initial ADC readings; and
calculate the average ADC values for every targeted flow value in the array.
6. The apparatus as claimed in claim 5, wherein the controller (110) configured to:
determine for ADC counts array whether the array is in ascending order;
compute the temperature constants for all the targeted flow values after calibration and stores in the array; and
calculate the average temperature constant by discarding initial three and last three constant values and store in the memory.
7. The apparatus as claimed in claim 1, wherein said first storage unit (112-1) adapted to store temperature constant computed during calibration and said second storage unit (112-2) adapted to store temperature constant computed during normal operation.
8. The apparatus as claimed in claim 1, wherein the controller (110) configured to compute required PWM count with temperature compensation for pumping the required flow during normal operation.
9. The apparatus as claimed in claim 1, wherein the controller (110) configured to:
initialize the temperature constant to be applied as constant calculated during calibration; and
calculate the temperature constant factor by computing the ratio of the temperature constant to be applied and temperature constant at calibration, wherein the PWM count to be applied is calculated as temperature constant factor multiplied by PWM count calculated from calibration table, which is applied as new PWM count in defined time intervals to achieve the required flow, which is greater than defined liters per minute (LPM) during normal operation.
10. A method (800) to compensate temperature of proportional valves for flow control, said method comprising:
regulating (802), at a pressure regulator configured in an apparatus, the flow of fluid to a desired quantity;
operating (804), a proportional valve coupled to the pressure regulator, upon receipt of a set of signals, to allow dispensation of the fluid;
generating (806), at a controller, the set of signals pertaining to pulse width modulation (PWM) count, the set of signals is received by the proportional valve; and
computing (808), at the controller, from the generated set of signals, the temperature constant for the generated set of signals, wherein, based on the determination of the temperature constant of the generated set of signals, the controller is configured to operate the proportional valve to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide sufficient quantity of fluid supply.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to a fluid control system, and more specifically, relates to an apparatus and method for temperature compensation in proportional valves for flow control.

BACKGROUND
[0002] Proportional valves play a vital role in the medical, foundry, process applications such as tensioning, spraying, blow moulding, analytical and test instrumentation applications. However, they can also be used in many other applications. In any of the applications where the proportional valves are used for long hours the behaviour of the valve changes because of the nature of the solenoid valve, its temperature gets increased, which in turn affects its actual intended behaviour.
[0003] The proportional valves are used for repeated flow control, they provide compact and cost-effective solutions for controlling pressure or flow at low flow rates. The proportional valve contains an inlet and an outlet for a fluid flow through the valve body, and a framework that is moveable along a longitudinal alignment from a closed position to an open position to control the flow of fluid through the valve.
[0004] During normal operation of the apparatus when it is used for long hours, the temperature of the proportional valve is increased, due to which even though the table is derived during calibration for flow and corresponding pulse width modulation (PWM) counts, during normal operation valve is not performing as derived/expected. It is the responsibility of the manufacturer of the apparatus to ensure the elements used to measure flow are accurate, fast and reliable.
[0005] A few existing techniques known in the art include a method using a differential pressure sensor to obtain a first differential pressure reading during which a predetermined pressure drop across the flow restriction portion. Another existing method relates to a mechanically operative gaseous flow valve that serves to compensate for pressure variations caused by fluctuations in temperature. Yet another existing method mention the valve controls communication between a source of pressurized gas and containers, which are to be charged with the gas. Although multiple techniques and frameworks exist today, these techniques suffer from significant drawbacks.
[0006] Therefore, it is desired to develop a means to compensate temperatures in a proportional valve that is effective, efficient and reliable for flow control.

OBJECTS OF THE PRESENT DISCLOSURE
[0007] An object of the present disclosure relates, in general, to a fluid control system, and more specifically, relates to an apparatus and method for temperature compensation in proportional valves for flow control.
[0008] Another object of the present invention is to provide an apparatus that calculates the temperature constant of the proportional control valve based on the derived equation during calibration and store it in the persistent storage to perform temperature compensation.
[0009] Another object of the present invention is to provide an apparatus that calculates the temperature constant factor of the proportional control valve based on the derived equation to perform temperature compensation during normal operation.
[0010] Another object of the present invention is to provide an apparatus for controlling the flow as defined /expected, where the proportional control valves are used.
[0011] Another object of the present invention is to provide an apparatus to use in any of the applications where the proportional control valves are used for flow control.
[0012] Yet another object of the present disclosure is to provide an apparatus for temperature compensation of the proportional control valve that is efficient and cost-effective.

SUMMARY
[0013] The present disclosure relates, in general, to a fluid control system, and more specifically, relates to an apparatus and method for temperature compensation in proportional valves for flow control.
[0014] In an aspect, the present disclosure relates to an apparatus to compensate the temperature of proportional valves for flow control, the apparatus comprising a pressure regulator configured in the apparatus, the pressure regulator regulates flow of fluid to a desired quantity, a proportional valve coupled to the pressure regulator, and operates upon receipt of a set of signals, to allow dispensation of the fluid, a controller operatively coupled to the proportional valve, the controller coupled to a memory comprising a first storage unit and a second storage unit, the memory storing instructions executable by the controller to generate the set of signals pertaining to pulse width modulation (PWM) count, the set of signals is received by the proportional valve and compute, from the generated set of signals, the temperature constant for the generated set of signals, wherein, based on the determination of the temperature constant of the generated set of signals, the controller is configured to operate the proportional valve to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide sufficient quantity of fluid supply.
[0015] According to an embodiment, the fluid is any or a combination of air and oxygen.
[0016] According to an embodiment, the pressure regulator receives the fluid from the proportional valve.
[0017] According to an embodiment, the apparatus comprises a sensor to measure the flow of the fluid.
[0018] According to an embodiment, the controller configured to initialize an array to store ADC value which is read for the defined sampling duration, for every PWM count applied, calculate the average ADC value after achieving the targeted flow value for the PWM count by discarding the initial ADC readings; and calculate the average ADC values for every targeted flow values in the array.
[0019] According to an embodiment, the controller configured to determine for ADC counts array whether the array is in ascending order, compute the temperature constants for all the targeted flow values after calibration and stores in the array and calculate the average constant by discarding initial three and last three constant values and store in the memory.
[0020] According to an embodiment, the first storage unit adapted to store temperature constant computed during calibration and the second storage unit adapted to store temperature constant computed during normal operation.
[0021] According to an embodiment, the controller configured to compute required PWM count with temperature compensation for pumping the required flow during normal operation.
[0022] According to an embodiment, the controller configured to initialize the temperature constant to be applied as constant calculated during calibration and calculate the temperature constant factor by computing the ratio of the temperature constant to be applied and temperature constant at calibration, wherein the PWM count to be applied is calculated as temperature constant factor multiplied by PWM count calculated from calibration table, which is applied as new PWM count in defined time intervals to achieve the required flow, which is greater than defined liters per minute (LPM) during normal operation.
[0023] In an aspect, the present disclosure relates to a method to compensate the temperature of proportional valves for flow control, the method comprising regulating, at a pressure regulator configured in the apparatus, the flow of fluid to a desired quantity, operating, a proportional valve coupled to the pressure regulator, upon receipt of a set of signals, to allow dispensation of the fluid; generating, at a controller, the set of signals pertaining to pulse width modulation (PWM) count, the set of signals is received by the proportional valve; and computing, at the controller, from the generated set of signals, the temperature constant for the generated set of signals, wherein, based on the determination of the temperature constant of the generated set of signals, the controller is configured to operate the proportional valve to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide sufficient quantity of fluid supply.
[0024] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0026] FIG. 1 illustrates an exemplary block diagram of the proposed apparatus for temperature compensation on proportional control valves, in accordance with an embodiment of the present disclosure.
[0027] FIG. 2 illustrates an exemplary flow diagram of the proposed method for constant computation during calibration for temperature compensation of an apparatus, in accordance with an embodiment of the present disclosure.
[0028] FIG. 3 illustrates an exemplary flow diagram of the proposed method for temperature compensation in a proportional control valve during normal operation of an apparatus, in accordance with an embodiment of the present disclosure.
[0029] FIG. 4 illustrates a standard flow chart representing proposed method for constant computation during calibration for temperature compensation of an apparatus, in accordance with an embodiment of the present disclosure.
[0030] FIG. 5 illustrates a standard flow chart representing proposed method for constant computation in a proportional control valve during normal operation of an apparatus, in accordance with an embodiment of the present disclosure.
[0031] FIG. 6 illustrates a graphical view showing the flow rate and function of PWM counts, in accordance with an embodiment of the present disclosure.
[0032] FIG. 7 illustrates a graphical view showing the function of PWM counts and flow rate, in accordance with an embodiment of the present disclosure.
[0033] FIG. 8 illustrates an exemplary flow chart of method for temperature compensation on proportional control valves, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0034] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0035] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0036] The present disclosure relates, in general, to a fluid control system, and more specifically, relates to an apparatus and method for temperature compensation in proportional valves for flow control. The apparatus and method of the present disclosure enable to overcome the limitations of the prior art by providing the proportional valves with temperature compensation control that can maintain the set flow rate regardless of the changes in the load pressure and its temperature.
[0037] The apparatus and method implemented are based on the derived constant computation during calibration, which is used to compute constant factor during the normal operation for updating pulse width modulation (PWM) count for required flow. The constant factor plays a major role in temperature compensation for flow control in normal operation of the apparatus. In an embodiment, the new PWM count is computed based on the constant factor and PWM count from the calibration table, which is applied only in controlled intervals and on the reception of flow command, which is greater than defined litres per minute (LPM). For the flow commands, which are not within controlled intervals, the PWM counts are used from the calibration table, which is generated during calibration.
[0038] In an embodiment, the method of the present disclosure is implemented based on the derived temperature constant computation during calibration and normal operation of the apparatus. During normal operation of the apparatus, on the reception of the flow command during first iteration, the apparatus initializes the ‘P’ms timer and applies the PWM count based on the count calculated from the calibration table. The analogue to digital converter (ADC) is read before the next PWM count is applied so that the stabilized ADC value is read and ‘P’ms timer is elapsed.
[0039] The method computes the initial temperature constant to be applied as the temperature constant calculated during calibration and computes the temperature constant factor as per the derived formula and apply the PWM count from the calibration table. In another embodiment, for the next iteration when ‘P’ms timer is expired and the flow command is greater than the defined LPM, the new temperature constant and temperature constant factor is computed based on the derived formula and verified whether the computed temperature constant factor is within the defined limits. The new PWM count is computed as temperature constant factor multiplied by PWM count calculated from calibration table, during normal operation in the apparatus. The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0040] FIG. 1 illustrates an exemplary block diagram of the proposed apparatus for temperature compensation on proportional control valves, in accordance with an embodiment of the present disclosure.
[0041] As illustrated in FIG. 1, an exemplary apparatus 100 can be configured to compensate the temperature of the proportional control valves for flow control. The proposed apparatus 100 can include a pressure regulator 102, proportional valves 104, a sensor 106, a controller 110, a first storage unit 112-1, a second storage unit 112-2 and a power source 108. The apparatus 100 has simple structure, productive process is relatively simple, the performance is reliable and has a good proportion of performance.
[0042] In an embodiment, the pressure regulator 102 is configured in the apparatus 100, the pressure regulator 102 regulates flow of fluid to the desired quantity, where the fluid can be any or a combination of air and oxygen. The proportional valve 104 is coupled to the pressure regulator 102, and operates upon receipt of a set of signals, to allow dispensation of the fluid. The apparatus 100 can include sensor 106 to measure the flow of the fluid. The fluid is sent through the pressure regulator 102, on the reception of flow command (also referred to as set of signals) from the controller 110, where the fluid is supplied in a controlled environment with the help of pressure regulator 102 through the proportional valves 104. In an embodiment, the apparatus 100 can include the power source 108 that is adapted to supply power to the apparatus 100.
[0043] The controller 110 operatively coupled to the proportional valve 104, the controller 110 operatively coupled to the memory, where the memory can include the first storage unit 112-1 and the second storage unit 112-2. The memory storing instructions executable by the controller to generate the set of signals pertaining to pulse width modulation (PWM) count, where the set of signals is received by the proportional valve 104. The controller 110 can compute, from the generated set of signals, the temperature constant for the generated set of signals. Based on the determination of the temperature constant of the generated set of signals, the controller 110 can be configured to operate the proportional valve 104 to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide a sufficient quantity of fluid supply.
[0044] The controller 110 may include one or more processor(s), where the one or more processor(s) can be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate data based on operational instructions. Among other capabilities, the one or more processor(s) are configured to fetch and execute computer-readable instructions stored in the first storage unit 122-1 and second storage unit 112-2. The first storage unit 112-1 and the second storage unit 112-2 can include any non-transitory storage device including, for example, non-volatile memory such as erasable programmable read-only memory (EPROM), flash memory, and the like.
[0045] In another embodiment, the controller 110 configured to initialize an array to store ADC value, which is read for the defined sampling duration, for every PWM count applied, the controller 110 can calculate the average ADC value after achieving the targeted flow value for the PWM count by discarding the initial ADC readings and calculate the average ADC values for every targeted flow value in the array. The controller 110 can determine for ADC counts array whether the array is in ascending order, compute the temperature constants for all the targeted flow values after calibration and stores in the array and calculate the average constant by discarding the initial three and last three constant values and store in the memory.
[0046] The memory can include the first storage unit 112-1 and the second storage unit 112-2, where the first storage unit 112-1 adapted to store temperature constant computed during calibration and the second storage unit 112-2 adapted to store temperature constant computed during normal operation.
[0047] The controller 110 is configured to compute the required PWM count with temperature compensation for pumping the required flow during normal operation. The controller 110 configured to initialize the temperature constant to be applied as constant calculated during calibration. The controller 110 can calculate the temperature constant factor by computing the ratio of the temperature constant to be applied and temperature constant at calibration, wherein the PWM count to be applied is calculated as temperature constant factor multiplied by PWM count calculated from the calibration table, which is applied as new PWM count in defined time intervals to achieve the required flow, which is greater than defined liters per minute (LPM) during normal operation.
[0048] The embodiments of the present disclosure described above provide several advantages. The apparatus 100 calculates the temperature constant of the proportional control valve based on the derived equation during calibration and store it in a persistent storage to perform temperature compensation. The apparatus 100 calculates the temperature constant factor of the proportional control valve based on the derived equation to perform temperature compensation during normal operation. The apparatus 100 can control flow as defined /expected, where the proportional control valves are used. The apparatus can be used in any of the applications where the proportional control valves are used for flow control and the apparatus is efficient and cost-effective.
[0049] FIG. 2 illustrates an exemplary flow diagram of the proposed method 200 for constant computation during calibration for temperature compensation of an apparatus, in accordance with an embodiment of the present disclosure.
[0050] As illustrated in FIG. 2, in an exemplary flow diagram of the proposed method 200, at block 202 during calibration, initialize the array to store ADC value, which is read for the defined sampling duration, for every PWM count applied. At block 204, calculate the average ADC value after achieving the targeted flow value for the PWM count by discarding the initial ADC readings till the ADC saturates. At block 206, calculate the average ADC values for every targeted flow value and store all the average ADC values in the array. At block 208, check for ADC counts array whether the array is in ascending order. At block 210, compute the temperature constants for all the targeted flow values after calibration is complete and store them in the array. At block 212, calculate the average temperature constant by discarding the initial three and last three constant values and storing it in the persistent memory.
[0051] FIG. 3 illustrates an exemplary flow diagram of the proposed method 300 for temperature compensation in a proportional control valve during normal operation of an apparatus, in accordance with an embodiment of the present disclosure.
[0052] As illustrated in FIG. 3, the method 300 includes at block 302, receive the flow command for every ‘N’ms cycle. Initialize ‘P’ms timer to apply temperature compensation after every timer expiry. At block 304, initially apply the PWM count calculated from the calibration table for flow control. Subsequently, read the ADC before the next PWM count is applied and ‘P’ms timer is elapsed. At block 306, initialize the temperature constant calculated during calibration to a new constant to be applied. Calculate the constant factor and read the PWM count to be applied from the calibration table. At block 308, check for ‘P’ms timer expiry and whether the flow command is greater than defined LPM, if both the conditions are satisfied the method allows reading the ADC count and calculates the working constant, which should be between defined ranges. At block 310, calculate the temperature constant factor by the ratio of working temperature constant with temperature constant at calibration. At block 312, calculate the new PWM count to be applied, which is the temperature constant factor multiplied by the PWM count calculated from the calibration table.
[0053] FIG. 4 illustrates a standard flow chart representing proposed method for constant computation during calibration for temperature compensation of an apparatus, in accordance with an embodiment of the present disclosure.
[0054] As illustrated in FIG. 4, the method 400 includes at block 402 initialize ADC array, at block 404, read the ADC value for the defined sampling duration for every PWM count applied and store the ADC value in the array. At block 406, calculate the average ADC value by discarding the initial ADC readings till the ADC saturates. At block 408, calculate the average ADC value after achieving the targeted flow value for the PWM count
[0055] At block 410, calculate the average ADC values for every targeted flow value and store all the average ADC values in the array. At block 412, determine if the ADC value is in ascending order, if the ADC value is not in ascending order, display the corresponding failure message. At block 414, compute the temperature constants for all the targeted flow values and store them in the array. At block 416, calculate the average temperature constant by discarding the initial three and the last three constant values and store it in the persistent memory.
[0056] FIG. 5 illustrates a standard flow chart representing proposed method for constant computation in a proportional control valve during normal operation of an apparatus, in accordance with an embodiment of the present disclosure.
[0057] As illustrated in FIG. 5, the method 500 includes at block 502, receive the flow command for every ‘N’ms cycle during inspiration cycle. Initialize ‘P’ms timer to apply temperature compensation after every timer expiry. At block 504, initially apply the PWM count calculated from calibration table for flow control. At block 506, initialize the temperature constant calculated during calibration to a new constant to be applied. Calculate the constant factor and read the PWM count to be applied from calibration table.
Temperature constant to be applied = temperature constant at calibration, Temperature constant factor = temperature constant to be applied/temperature constant at calibration =1.0.
PWM count applied = PWM count from calibration table.
[0058] At block 508, receive flow commands for the next iterations, apply the PWM count calculated from calibration table. At block 510, check for ‘P’ms timer expiry and whether the flow command is greater than defined LPM, if both the conditions are satisfied the method allows at block 512, reading the ADC count and calculates the working constant, which should be between defined ranges. Calculate the temperature constant factor by the ratio of working temperature constant with temperature constant at calibration.
[0059] New temperature constant = (PWM count applied * PWM count applied)/ADC count,
Ratio to limit the new temperature constant = new temperature constant/ temperature constant at calibration
Working temperature constant = 0.01*new temperature constant + (0.99 *previous working temperature constant)
Temperature constant factor = working temperature constant/temperature constant at calibration.
[0060] At block 514, receive flow command for the next iterations apply the PWM count calculated from the calibration table.
[0061] FIG. 6 illustrates a graphical view 600 showing the flow rate and function of PWM counts, in accordance with an embodiment of the present disclosure. FIG. 6 depicts the flow rate as a function of PWM counts with original flow rate, flow rate without temperature compensation and flow rate with temperature compensation of the apparatus.
[0062] FIG. 7 illustrates a graphical view 700 showing the function of PWM counts and flow rate, in accordance with an embodiment of the present disclosure. FIG. 7 illustrates the function of PWM counts without temperature compensation and with temperature compensation of the apparatus.
[0063] FIG. 8 illustrates an exemplary flow chart of method for temperature compensation on proportional control valves, in accordance with an embodiment of the present disclosure.
[0064] Referring to FIG. 8, the method includes at block 802, the pressure regulator configured in the apparatus, the pressure regulator regulates flow of fluid to a desired quantity. At block 804, the proportional valve coupled to the pressure regulator, and operates upon receipt of a set of signals, to allow dispensation of the fluid. At block 806, the controller operatively coupled to the proportional valve, coupled to a memory, the memory storing instructions executable by the controller to generate the set of signals pertaining to pulse width modulation (PWM) count, the set of signals is received by the proportional valve.
[0065] At block 810, the controller configured to compute, from the generated set of signals, the temperature constant for the generated set of signals, wherein, based on the determination of the temperature constant of the generated set of signals, the controller is configured to operate the proportional valve to allow dispensation of a predetermined quantity of the fluid, the predetermined quantity determined as being required to provide sufficient quantity of fluid supply.
[0066] It will be apparent to those skilled in the art that the apparatus 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0067] The present disclosure provides an apparatus that calculates the temperature constant of the proportional control valve based on the derived equation during calibration and store it in the persistent storage to perform temperature compensation.
[0068] The present disclosure provides an apparatus that calculates the temperature constant factor of the proportional control valve based on the derived equation to perform temperature compensation during normal operation.
[0069] The present disclosure provides an apparatus for controlling the flow as defined /expected, where the proportional control valves are used.
[0070] The present disclosure provides an apparatus to use in any of the applications where the proportional control valves are used for flow control.
[0071] The present disclosure provides an apparatus for temperature compensation of the proportional control valve that is efficient and cost-effective.