Gas cabinets are often used in industry to control the flow of gas from a source such as a gas cylinder to a destination such as a piece of industrial equipment. Traditional gas cabinets often use spring loaded regulators to control cylinder pressure, keeping the pressure to a usable level. Compressed gases may have initial cylinder pressures of up to 3,000 pounds per square inch (psi), and the cylinder may have a change-out pressure 200-300 psi. Thus, when a cylinder is full of gas, the pressure is 10× (or more) higher than when the cylinder is eventually changed out.
A phenomenon called “Supply Pressure Effect” (SPE) occurs in pressure regulators where the outlet pressure rises as the cylinder pressure drops. This is because the regulator spring produces a constant force on a diaphragm, which pushes down on a poppet, opening the flow path through the regulator. To counter this spring force, the gas pressure pushes the regulator open by applying pressure to the poppet and under the diaphragm. As the cylinder pressure decays over time, less force is applied to the poppet, and the spring above the diaphragm continues to open the regulator, increasing the outlet pressure.
Depending on the regulator's required flow rate, the rise in pressure can be significant. The (SPE) may be stated in pressure rise per 100 psi loss of pressure in the cylinder. The (SPE) can vary from a low of 0.25 psi for low flow regulators to over 3.5 psi for higher flow regulators. Because of this, a cylinder with a starting pressure of 2,200 psi and a final change-out pressure of 200 psi could see the outlet pressure rise in the system anywhere from 5 to 70 psi. This rise in outlet pressure can play havoc with downstream equipment, alarms, set points, and potential tool shutdowns.
To minimize the supply pressure effect, regulators are sized to deliver flow rates as close as possible to the process tool's requirements, at the desired pressure when the cylinder is full. The regulator must also deliver adequate flow when the gas cylinder is low on gas. As the cylinder pressure decays to a certain point, the flow is not sufficient for the needs of the process, and the cylinder is changed out, even though it still contains a significant amount of gas. This may result in two potential expenses for the gas cabinet owner: first, a certain amount of gas, which was paid for, is returned to the supplier in the gas cylinder. In some cases, this can be up to 20% of the cylinder's contents. The cost of this wasted gas can be significant. Secondly, gas suppliers often charge to dispose of this residual gas since it is usually hazardous. Accordingly, many problems exist with current gas cabinets.
Embodiments described herein are directed to regulating pressure and/or fluid flow within a system. In one embodiment, a system for regulating pressure includes the following: a controller, a pneumatic pressure regulator that includes a dome configured to adjust pressure within the system, a current-to-pneumatic converter configured to convert an electrical current signal to a pneumatic pressure signal, and a pressure transducer arranged downstream from the pneumatic pressure regulator. The controller receives an outlet pressure signal from the pressure transducer indicating a current level of system pressure, compares the current system pressure level to a specified desired system pressure level and, upon determining that the current system pressure level is above or below the desired system pressure level, sends an electrical current signal to the current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to the dome of the pneumatic pressure regulator to raise or lower system pressure to the desired system pressure level.
In some examples, the system may include a gas cabinet for regulating gas pressure. The gas cabinet may include at least one gas input line and at least one gas output line. The system may form a control loop where outlet pressure from the gas cabinet is kept at a substantially steady pressure level. The control loop may maintain the substantially steady pressure level regardless of pressure level remaining in a gas cylinder connected to the gas input line. Additionally or alternatively, the control loop may maintain the substantially steady pressure level regardless of a speed of consumption by one or more process tools connected to the gas output line. The control loop may also maintain a substantially steady pressure level until supply pressure drops below a specified minimum supply pressure.
In some examples, the gas cabinet may include regulators sized for a desired system pressure level. The controller may also send the electrical current signal to the current-to-pneumatic converter upon determining that the pressure level is above the desired system pressure level by at least a specified amount or is below the desired system pressure level by at least a specified amount. In some examples, the pressure transducer may be a pressure switch.
In another embodiment, a system is provided for regulating flow. The system includes a controller, a pneumatic pressure regulator that includes a dome configured to increase pressure or relieve pressure within the system, a current-to-pneumatic converter configured to convert an electrical current signal to a pneumatic pressure signal, and a flow meter arranged downstream from the pneumatic pressure regulator. The controller receives a flow signal from the flow meter indicating a current level of system flow, compares the current system flow level to a specified desired system flow level and, upon determining that the current system flow level is above or below the desired system flow level, sends an electrical current signal to the current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to the dome of the pneumatic pressure regulator to raise or lower system flow level to the desired system flow level.
In some examples, the system includes or is incorporated within a gas cabinet for regulating gas flow through gas input lines and through gas output lines. In some examples, at least one of the gas input lines is connected to a gas cylinder. In some examples, at least one of the gas output lines is connected to a process tool. The system may form a control loop where outlet gas flow from the gas cabinet is kept at a substantially steady system flow level. The control loop may maintain the substantially steady system flow level regardless of pressure level remaining in any gas cylinders connected to the gas input line. The control loop may maintain the substantially steady system flow level regardless of a speed of consumption by the process tools connected to the gas output line.
A method for regulating pressure may also be provided, which includes receiving an outlet pressure signal from a pressure transducer indicating a current level of system pressure, comparing the current system pressure level to a specified desired system pressure level and, upon determining that the current system pressure level is above or below the desired system pressure level, sending an electrical current signal to a current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to a dome element of a pneumatic pressure regulator to raise or lower system pressure to the desired system pressure level. The method may further include maintaining the desired system pressure level to within a specified acceptable deviation in system pressure level. These method steps may be performed by an embedded controller in a gas cabinet.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Additional features and advantages will be set forth in the description which follows, and in part will be apparent to one of ordinary skill in the art from the description or may be learned by the practice of the teachings herein. Features and advantages of embodiments described herein may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the embodiments described herein will become more fully apparent from the following description and appended claims.
To further clarify the above and other features of the embodiments described herein, a more particular description will be rendered by reference to the appended drawings. It is appreciated that these drawings depict only examples of the embodiments described herein and are therefore not to be considered limiting of its scope. The embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Embodiments described herein are directed to regulating pressure and/or fluid flow within a system. In one embodiment, a system for regulating pressure includes the following: a controller, a pneumatic pressure regulator that includes a dome configured to adjust pressure within the system, a current-to-pneumatic converter configured to convert an electrical current signal to a pneumatic pressure signal, and a pressure transducer arranged downstream from the pneumatic pressure regulator. The controller receives an outlet pressure signal from the pressure transducer indicating a current level of system pressure, compares the current system pressure level to a specified desired system pressure level and, upon determining that the current system pressure level is above or below the desired system pressure level, sends an electrical current signal to the current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to the dome of the pneumatic pressure regulator to raise or lower system pressure to the desired system pressure level.
In some examples, the system may include a gas cabinet for regulating gas pressure. The gas cabinet may include at least one gas input line and at least one gas output line. The system may form a control loop where outlet pressure from the gas cabinet is kept at a substantially steady pressure level. The control loop may maintain the substantially steady pressure level regardless of pressure level remaining in a gas cylinder connected to the gas input line. Additionally or alternatively, the control loop may maintain the substantially steady pressure level regardless of a speed of consumption by one or more process tools connected to the gas output line. The control loop may also maintain a substantially steady pressure level until supply pressure drops below a specified minimum supply pressure.
In some examples, the gas cabinet may include regulators sized for a desired system pressure level. The controller may also send the electrical current signal to the current-to-pneumatic converter upon determining that the pressure level is above the desired system pressure level by at least a specified amount or is below the desired system pressure level by at least a specified amount. In some examples, the pressure transducer may be a pressure switch.
In another embodiment, a system is provided for regulating flow. The system includes a controller, a pneumatic pressure regulator that includes a dome configured to increase pressure or relieve pressure within the system, a current-to-pneumatic converter configured to convert an electrical current signal to a pneumatic pressure signal, and a flow meter arranged downstream from the pneumatic pressure regulator. The controller receives a flow signal from the flow meter indicating a current level of system flow, compares the current system flow level to a specified desired system flow level and, upon determining that the current system flow level is above or below the desired system flow level, sends an electrical current signal to the current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to the dome of the pneumatic pressure regulator to raise or lower system flow level to the desired system flow level.
In some examples, the system includes or is incorporated within a gas cabinet for regulating gas flow through gas input lines and through gas output lines. In some examples, at least one of the gas input lines is connected to a gas cylinder. In some examples, at least one of the gas output lines is connected to a process tool. The system may form a control loop where outlet gas flow from the gas cabinet is kept at a substantially steady system flow level. The control loop may maintain the substantially steady system flow level regardless of pressure level remaining in any gas cylinders connected to the gas input line. The control loop may maintain the substantially steady system flow level regardless of a speed of consumption by the process tools connected to the gas output line.
A method for regulating pressure may also be provided, which includes receiving an outlet pressure signal from a pressure transducer indicating a current level of system pressure, comparing the current system pressure level to a specified desired system pressure level and, upon determining that the current system pressure level is above or below the desired system pressure level, sending an electrical current signal to a current-to-pneumatic converter that converts the electrical current signal to a pneumatic pressure signal that is sent to a dome element of a pneumatic pressure regulator to raise or lower system pressure to the desired system pressure level. The method may further include maintaining the desired system pressure level to within a specified acceptable deviation in system pressure level. These method steps may be performed by an embedded controller in a gas cabinet.
Embodiments described herein may implement various types of controllers, processors, embedded computing systems or other types of computing systems. These computing systems may include, without limitation, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), systems-on-a-chip, or other special purpose processors. The computing systems may also include, without limitation, desktop or mainframe computers, laptop computers, tablet computers, wearable devices, mobile phones, electronic appliances, and other types of computing systems.
As used herein, the term “computing system” includes any device, system, or combination thereof that includes at least one processor, and a physical and tangible computer-readable memory capable of having thereon computer-executable instructions that are executable by the processor. A computing system may be distributed over a network environment and may include multiple constituent computing systems (e.g. a cloud computing environment). In a cloud computing environment, program modules may be located in local and/or remote memory storage devices.
As described herein, a computing system may also contain communication channels that allow the computing system to communicate with other message processors over a wired or wireless network. Such communication channels may include hardware-based receivers, transmitters or transceivers, which are configured to receive data, transmit data, or both. Embodiments described herein may also include physical computer-readable media for carrying or storing computer-executable instructions and/or data structures. Such computer-readable media can be any available physical media that can be accessed by a general-purpose or special-purpose computing system.
Still further, system architectures described herein can include a plurality of independent components that each contribute to the functionality of the system as a whole. This modularity allows for increased flexibility when approaching issues of platform scalability and, to this end, provides a variety of advantages. System complexity and growth can be managed more easily through the use of smaller-scale parts with limited functional scope. Platform fault tolerance is enhanced through the use of these loosely coupled modules. Individual components can be grown incrementally as business needs dictate. Modular development also translates to decreased time to market for new functionality. New functionality can be added or subtracted without impacting the core system.
Still further, system architectures described herein can include a plurality of independent components that each contribute to the functionality of the system as a whole. This modularity allows for increased flexibility when approaching issues of platform scalability and, to this end, provides a variety of advantages. System complexity and growth can be managed more easily through the use of smaller-scale parts with limited functional scope. Platform fault tolerance is enhanced through the use of these loosely coupled modules. Individual components can be grown incrementally as business needs dictate. Modular development also translates to decreased time to market for new functionality. New functionality can be added or subtracted without impacting the core system.
The following will provide, with reference to
The system 100 may also include hardware components including a pneumatic pressure regulator 104, a current-to-pneumatic converter 106, and a pressure transducer 109. Other hardware components and/or software components may be implemented within system 100. The system may, for example, include program modules for performing different functions. The program modules may be hardware-based, software-based, or may include a combination of hardware and software. Each program module may use or represent computing hardware and/or software to perform specified functions, including those described herein below.
For example, in some embodiments, the controller 101 may be communicatively connected to a communications module. The communications module may include any wired or wireless communication means that can receive and/or transmit data to or from other computer systems. These communication means may include radios including, for example, a hardware-based receiver, a hardware-based transmitter, or a combined hardware-based transceiver capable of both receiving and transmitting data. The radios may be WIFI radios, cellular radios, Bluetooth radios, global positioning system (GPS) radios, or other types of radios. Such a communications module may be configured to interact with databases, mobile devices (such as mobile phones or tablets), embedded systems, or other types of computing systems.
Thus, the controller 101 may communicate with components and modules within the system 100, as well as components and/or modules that are external to the system 100. In some embodiments, the controller 101 may communicate with the current-to-pneumatic converter 106, for example, sending an electric signal 108 that may indicate that pressure is to be increased or decreased. The current-to-pneumatic converter 106 may be configured to convert an electrical current signal to a pneumatic pressure signal 107. This pneumatic pressure signal 107 may be sent to the pneumatic pressure regulator 105, which includes a dome 105 configured to adjust pressure within the system. The pneumatic pressure regulator 104 may then activate or actuate the dome 105 to increase or decrease pressure within the system.
In one embodiment, the controller 101 of system 100 may receive an outlet pressure signal 110 from the pressure transducer 109 indicating a current level of system pressure 111. Upon receiving this outlet pressure signal 110, the controller compares the current system pressure level to a specified desired system pressure level 103. This desired system pressure level 103 may be set by a worker, manager, manufacturer, or other individual. The desired system pressure level 103 may indicate the pressure level that is to be maintained between one or more of the components of the system 100 including any gas lines in to the system, gas lines out of the system, the pneumatic pressure regulator 104 and the pressure transducer. At least in some cases, the system pressure level 111 may be different when measured at different components.
Accordingly, in such cases, the desired pressure level 103 may specify where the pressure measurement is to be taken. In some embodiments, the pressure transducer 109 detects the current system pressure level 111 and generates the outlet pressure signal 110 indicating to the controller 101 that the controller 101 is to increase or decrease system pressure using the pneumatic pressure regulator 104. In some cases, the pressure transducer 109 may be a pressure switch or other actuator that is capable of reading or responding to a given pressure level and generating an outlet pressure signal.
Accordingly, upon determining that the current system pressure level 111 is above or below the desired system pressure level 103, the controller 101 may send an electrical current signal 108 to the current-to-pneumatic converter 106 that converts the electrical current signal to a pneumatic pressure signal 107 that is sent to the dome 105 of the pneumatic pressure regulator 104 to raise or lower system pressure to the desired system pressure level. Thus, in cases where a pneumatic pressure regulator is used, the pneumatic pressure signal 107 will indicate how the dome 105 is to be operated to increase or decrease the system pressure level 111. In cases where another (non-pneumatic) type of pressure regulator is used, the controller may generate a control signal that goes directly to the pressure regulator and applies the appropriate changes to the dome 105 to increase or decrease pressure depending on what was indicated in the outlet pressure signal 110.
For example, as shown in
Accordingly, as the gas pressure in the supply line 302 decreases, the controller 201 may receive inputs from a pressure transducer 205 indicating the decline in pressure. The controller may determine that the current system pressure level is too low and may send an electrical current signal to the current-to-pneumatic converter 203 that converts the electrical current signal to a pneumatic pressure signal 202 that is sent to the dome 206 of the pneumatic pressure regulator to raise or lower system pressure to a specified system pressure level. Excess pressure may also be relieved via the pneumatic exhaust 204.
Accordingly, in this manner, the system 200 forms a control loop where outlet pressure from the gas cabinet 301 is kept at a substantially steady pressure level, even as input pressure declines. Initially, due to the relatively high pressure in the input line 302, the gas cabinet 301 may decrease the pressure to maintain a substantially steady pressure level in the gas output line 304. Then, as the pressure in the gas input line 302 drops, the gas cabinet 301 may increase the pressure level to maintain the steady pressure level in the gas output line 304. Thus, the gas cabinet 301 may maintain a steady output pressure in the gas output line 304 regardless of the pressure level remaining in the gas cylinder 303 (or other gas source) connected to the gas input line 302. This control loop may also maintain a steady pressure level regardless of the speed of consumption by the industrial tools 305 connected to the gas output line 304. Accordingly, even if the industrial tool's demand for gas fluctuates over time, and if the pressure in the gas output line 304 varies along with the demand, the control loop may ensure that the system pressure level stays at a specified pressure, or within a certain pressure range.
Once the gas supply 303 begins to run out, the supply pressure may drop below a specified minimum pressure level. The control loop within the system 100 may be configured to maintain a steady pressure level until supply pressure drops below the specified minimum supply pressure. Once the minimum supply pressure is no longer being met, the gas supply container will need to be replaced. The embodiments herein, however, may allow more of the gas in the container to be used than in traditional systems. By removing pressure when the gas cylinder 303 is full, and by adding pressure when the gas cylinder is near empty, the systems herein may allow higher pressure cylinders to be used, and may also allow more of the gas to be used before having to replace the cylinders.
In some embodiments, the gas cabinet 301 may include regulators that are sized for a specific system pressure level. Thus, for example, if a user specifies a desired pressure level 103 for the system 100 of
In some cases, the controller in the gas cabinet 301 may be configured to take no action until the system pressure level is sufficiently above or below the desired pressure level 103. For example, the controller 101 may be configured to send the electrical current signal 108 to the current-to-pneumatic converter 106 upon determining that the pressure level 111 is above the desired system pressure level 103 by at least a specified amount or is below the desired system pressure level by at least a specified amount. The range may be plus or minus 10 psi, 20 psi, 50 psi, 100 psi, or some other range. Once outside of this range, the controller 101 may then take action to raise or lower the system pressure. Then, once the pneumatic pressure regulator has actuated the dome 105 to increase or decrease system pressure to within the specified range, the controller may idle and wait for a new outlet pressure signal indicating that the system pressure needs to be altered.
The embodiments herein may not only regulate pressure within a system, but they may (additionally or alternatively) regulate flow within the system. For example, as shown in
The controller 401 may receive a flow signal 410 from the flow meter 409 indicating a current level of system flow 411. The controller 401 may then compare the current system flow level 411 to a specified desired system flow level 403 stored in memory 402. If the controller 401 determines that the current system flow level 411 is above or below the desired system flow level 403, the controller may send an electrical current signal 408 to the current-to-pneumatic converter 406 that converts the electrical current signal to a pneumatic pressure signal 407. That pneumatic pressure signal may then be sent to the dome 405 of the pneumatic pressure regulator 404 to raise or lower system flow level to the desired system flow level 403.
As with system pressure, the system flow level may fluctuate as a gas supply container changes in pressure over time. Initially, when the container (e.g. 303 of
As with the systems 100 and 200, the system 400 may be incorporated within or may itself be a gas cabinet. The gas cabinet may be used to regulate gas flow through gas input line and gas output lines. As shown in
Accordingly, the systems above may provide a feedback control loop that ensures that a substantially constant pressure or flow rate is maintained. This feedback control loop may be referred to as a “closed loop pressure control.” This closed loop pressure control (or flow control) may be provided in a cylinder gas cabinet. A controller (e.g. 101 of
This arrangement of components may provide a highly accurate system with a control loop that keeps the outlet pressure of the gas cabinet at a steady pressure regardless of either the pressure remaining in the gas cylinder, or the speed of consumption by the process tools (e.g., 305 of
In view of the systems and architectures described above, methodologies that may be implemented in accordance with the disclosed subject matter will be better appreciated with reference to the flow chart of
Method 500 includes receiving an outlet pressure signal from a pressure transducer indicating a current level of system pressure (510). For example, controller 101 may receive outlet pressure signal 110 from a pressure transducer 109 or pressure switch. The outlet pressure signal 110 may indicate the current system pressure level 111 at a specific point within the system 100, or within the system in general.
Method 500 next includes comparing the current system pressure level to a specified desired system pressure level (520). The controller 101 may compare the current system pressure level 111 to a desired pressure level 103. This desired pressure level may be set by a machine operator, gas cabinet operator, gas cabinet manufacturer or owner or other user. The desired pressure level may be specific for each gas input or output line or may apply to the system 100 in general. For instance, if the gas cabinet had multiple gas input lines and multiple gas output lines, each gas line may have its own desired pressure level 103 which would be maintained by the system 100.
Then, upon determining that the current system pressure level 111 is above or below the desired system pressure level, method 500 includes sending an electrical current signal 108 to a current-to-pneumatic converter 106 that converts the electrical current signal to a pneumatic pressure signal 107 that is sent to a dome element 105 of a pneumatic pressure regulator 104 to raise or lower system pressure to the desired system pressure level (530). This desired system pressure level is then maintained via the control loop. If the pressure (or flow) level is too high or too low (e.g., outside of an acceptable deviation in system pressure level or flow), then the controller will receive an outlet pressure signal indicating that pressure has changed, and that the regulator 104 should be used to compensate for this change in pressure. Accordingly, at least in some embodiments, a user can simply set a desired pressure level, and the gas cabinet can maintain that pressure for much longer than in traditional systems. This allows more gas to be used before having to refill the gas containers, saving the owner both time and money.
The concepts and features described herein may be embodied in other specific forms without departing from their spirit or descriptive characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/671,121, entitled “Pressure Control for Gas System Payback,” filed on May 14, 2018, which application is incorporated by reference herein in its entirety.
Number | Date | Country | |
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62671121 | May 2018 | US |