Patent Description:
This disclosure generally relates to pressure sensors. More specifically, this disclosure relates to a pressure sensor with flow porting having an integral flame-proof safety mechanism.

Pressure transmitters are routinely used in industrial processes and other systems to capture pressure measurements. For Health, Safety, and Environmental (HS&E) purposes, it is often a requirement that a pressure transmitter meter body be flame-proof (also known as explosion-proof or "Ex d"). An energized device such as a pressure transmitter meter body is considered to be flame-proof when the device can both (i) contain the pressure generated by an explosive gas mixture being ignited within the device itself and (ii) prevent an explosion flame front from escaping the device. The ability to contain the pressure generated by an explosion and the ability to prevent the flame front from leaving the device help to ensure that no explosive gas mixture outside the device would be ignited. This can be particularly important in industrial processes or other systems where an explosive gas mixture may exist in the ambient environment surrounding the device, such as in an oil and gas refinery.

Pressure containment can normally be achieved by the construction of pressure transmitter meter bodies themselves, which are designed to contain pressure as part of their normal operation in measuring pressure. One conventional technique for containing flame fronts is to attenuate the thermal energy in a flame prior to the flame front being able to leave the device, thereby extinguishing the flame and preventing any external explosive gas mixtures from igniting. For example, some conventional pressure sensors utilize special add-on components called "flame arresters" to contain flame fronts. However, the flame arresters occupy valuable space within a pressure sensor and often require machining of special features to hold the flame arrestors, which increases manufacturing and assembly costs. <CIT> relates to a thermal protection element which is arranged on the front side for the protection of a membrane of a pressure sensor that is subjected to pressure. <CIT> relates to a field device and method of manufacturing a field device including a capillary tube having a non-cylindrical lumen. <CIT> relates to modular pressure transmitters with flame arresting or quenching headers coupled to process pressure lines.

This disclosure provides a pressure sensor with flow porting having an integral flame-proof safety mechanism.

In a first embodiment, an apparatus includes a sensor body and a sensor configured to measure pressure according to claim <NUM>.

In a second embodiment, a system includes a manifold and a pressure sensor mounted to the manifold according to claim <NUM>.

In a third embodiment, a method according to claim <NUM> includes providing at least one input pressure to a sensor from at least one pressure input in or on a sensor body.

<FIG>, discussed below, and the various embodiments describe the principles of the present invention.

<FIG> illustrates an example industrial process control and automation system <NUM> according to this disclosure. As shown in <FIG>, the system <NUM> includes various components that facilitate production or processing of at least one product or other material. For instance, the system <NUM> can be used to facilitate control over components in one or multiple industrial plants. Each plant represents one or more processing facilities (or one or more portions thereof), such as one or more manufacturing facilities for producing at least one product or other material. In general, each plant may implement one or more industrial processes and can individually or collectively be referred to as a process system. A process system generally represents any system or portion thereof configured to process one or more products or other materials in some manner.

In <FIG>, the system <NUM> includes one or more sensors 102a and one or more actuators 102b. The sensors 102a and actuators 102b represent components in a process system that may perform any of a wide variety of functions. For example, the sensors 102a could measure a wide variety of characteristics in the process system, such as pressure, temperature, or flow rate. Also, the actuators 102b could alter a wide variety of characteristics in the process system. Each of the sensors 102a includes any suitable structure for measuring one or more characteristics in a process system. Each of the actuators 102b includes any suitable structure for operating on or affecting one or more conditions in a process system.

At least one network <NUM> is coupled to the sensors 102a and actuators 102b. The network <NUM> facilitates interaction with the sensors 102a and actuators 102b. For example, the network <NUM> could transport measurement data from the sensors 102a and provide control signals to the actuators 102b. The network <NUM> could represent any suitable network or combination of networks. As particular examples, the network <NUM> could represent at least one Ethernet network, electrical signal network (such as a HART or FOUNDATION FIELDBUS network), pneumatic control signal network, or any other or additional type(s) of network(s).

The system <NUM> also includes various controllers <NUM>. The controllers <NUM> can be used in the system <NUM> to perform various functions in order to control one or more industrial processes. For example, a first set of controllers <NUM> may use measurements from one or more sensors 102a to control the operation of one or more actuators 102b. A second set of controllers <NUM> could be used to optimize the control logic or other operations performed by the first set of controllers. A third set of controllers <NUM> could be used to perform additional functions.

Controllers <NUM> are often arranged hierarchically in a system. For example, different controllers <NUM> could be used to control individual actuators, collections of actuators forming machines, collections of machines forming units, collections of units forming plants, and collections of plants forming an enterprise. A particular example of a hierarchical arrangement of controllers <NUM> is defined as the "Purdue" model of process control. The controllers <NUM> in different hierarchical levels can communicate via one or more networks <NUM> and associated switches, firewalls, and other components.

Each controller <NUM> includes any suitable structure for controlling one or more aspects of an industrial process. At least some of the controllers <NUM> could, for example, represent proportional-integral-derivative (PID) controllers or multivariable controllers, such as Robust Multivariable Predictive Control Technology (RMPCT) controllers or other types of controllers implementing model predictive control or other advanced predictive control. As a particular example, each controller <NUM> could represent a computing device running a real-time operating system, a WINDOWS operating system, or other operating system.

Operator access to and interaction with the controllers <NUM> and other components of the system <NUM> can occur via various operator consoles <NUM>. Each operator console <NUM> could be used to provide information to an operator and receive information from an operator. For example, each operator console <NUM> could provide information identifying a current state of an industrial process to the operator, such as values of various process variables and warnings, alarms, or other states associated with the industrial process. Each operator console <NUM> could also receive information affecting how the industrial process is controlled, such as by receiving setpoints or control modes for process variables controlled by the controllers <NUM> or other information that alters or affects how the controllers <NUM> control the industrial process.

Multiple operator consoles <NUM> can be grouped together and used in one or more control rooms <NUM>. Each control room <NUM> could include any number of operator consoles <NUM> in any suitable arrangement. In some embodiments, multiple control rooms <NUM> can be used to control an industrial plant, such as when each control room <NUM> contains operator consoles <NUM> used to manage a discrete part of the industrial plant.

Each operator console <NUM> includes any suitable structure for displaying information to and interacting with an operator. For example, each operator console <NUM> could include one or more processing devices <NUM>, such as one or more processors, microprocessors, microcontrollers, field programmable gate arrays, application specific integrated circuits, discrete logic devices, or other processing or control devices. Each operator console <NUM> could also include one or more memories <NUM> storing instructions and data used, generated, or collected by the processing device(s) <NUM>. Each operator console <NUM> could further include one or more network interfaces <NUM> that facilitate communication over at least one wired or wireless network, such as one or more Ethernet interfaces or wireless transceivers.

At least one of the sensors 102a in <FIG> could represent a pressure sensor. As noted above, a pressure sensor often needs to be flame-proof (explosion-proof or "Ex d"). In accordance with this disclosure, a pressure sensor meter body incorporates a number of unique internal flow paths that are used to transfer process pressure to a sensor, and these flow paths are also designed to comply with suitable flame-proof requirements. For example, a potential explosion within the meter body could be caused by an explosive gas mixture reaching an electronic sensor and igniting. The design of the pressure sensor meter body can help to ensure that the pressure generated by an explosion within the pressure sensor is contained within the pressure sensor. Also, the unique flow paths in the pressure sensor meter body help to ensure that a flame, front is extinguished by absorbing the thermal energy in a flame before the flame is able to exit the meter body (either to an industrial process or to the outside ambient environment).

Among other things, the pressure sensor utilizes a unique meter body construction that has thick walls relative to the internal volume that an explosive gas mixture can encompass. Also, the meter body includes flow paths that are circuitous or helical in nature or include sharp turns and that have relatively small cross-sections relative to their lengths. These design features enable cost-effective and highly accurate performance of the pressure sensor while also supporting an integral flame-proof safety mechanism within the pressure sensor. Thus, the pressure sensor can inherently satisfy flame-proof requirements based on its design and avoid the need for special features like flame arrestors that can occupy space and increase manufacturing and assembly costs.

Additional details regarding a pressure sensor with flow porting having an integral flame-proof safety mechanism are provided below. Note that these details relate to specific implementations of the pressure sensor and that other implementations could vary as needed or desired.

Although <FIG> illustrates one example of an industrial process control and automation system <NUM>, various changes may be made to <FIG>. For example, industrial control and automation systems come in a wide variety of configurations. The system <NUM> shown in <FIG> is meant to illustrate one example operational environment in which a pressure sensor could be used.

<FIG> illustrates an example pressure sensor <NUM> according to this disclosure. For ease of explanation, the pressure sensor <NUM> may be described as being used in the industrial process control and automation system <NUM> of <FIG>. However, the pressure sensor <NUM> could be used in any other suitable system, and the system need not relate to industrial process control and automation.

As shown in <FIG>, the pressure sensor <NUM> includes an adapter <NUM> and at least one sensor <NUM>. The adapter <NUM> denotes a portion of the pressure sensor <NUM> in which wires or other signal conductors can be connected to the sensor <NUM>. The outer surface of the adapter <NUM> can also be threaded or otherwise configured to facilitate attachment of the pressure sensor <NUM> to a larger device or system. The adapter <NUM> could be formed from any suitable material(s) and in any suitable manner. As a particular example, the adapter <NUM> could be formed from metal.

The sensor <NUM> denotes a structure that senses one or more input pressures and that outputs at least one signal based on the input pressure(s). For example, the sensor <NUM> could output an electrical signal whose voltage or current varies proportionally with a single pressure or with a differential pressure. The sensor <NUM> includes any suitable pressure sensor, such as a piezo-resistive or capacitive sensor. Multiple sensors <NUM> could also be used, such as sensors that output both differential and static pressure measurements. Also, the multiple sensors <NUM> may or may not be implemented on a single integrated circuit chip. Each sensor <NUM> includes any suitable structure for measuring pressure.

The pressure sensor <NUM> also includes a coplanar body <NUM>, which denotes a portion of the pressure sensor <NUM> in which multiple pressure inputs are located. The pressure inputs are generally located on a common plane, which is why the body <NUM> is referred to as a "coplanar" body. The coplanar body <NUM> could be formed from any suitable material(s) and in any suitable manner. As a particular example, the coplanar body <NUM> could be formed from metal. Note that the adapter <NUM> and the coplanar body <NUM> could be formed integrally or as separate pieces that are connected together, such as by welding.

The pressure inputs in the pressure sensor <NUM> are implemented using a high-pressure barrier diaphragm <NUM> and a low-pressure barrier diaphragm <NUM>. Each of the barrier diaphragms <NUM> and <NUM> represents a barrier that allows pressure to be transmitted into the pressure sensor <NUM> while preventing process fluid (such as oil, gas, or other high pressure and corrosive fluid) from entering into the pressure sensor <NUM>. The barrier diaphragms <NUM> and <NUM> represent flexible membranes that can move up or down in <FIG> based on the amount of pressure applied to the barrier diaphragms <NUM> and <NUM>.

Each of the barrier diaphragms <NUM> and <NUM> denotes any suitable flexible membrane, such as a metallic membrane. Each of the barrier diaphragms <NUM> and <NUM> could also have any suitable size, shape, and dimensions. In particular embodiments, the barrier diaphragms <NUM> and <NUM> are small enough and spaced apart to fit within the established bolt pattern for industry-standard DIN manifolds. This allows the pressure sensor <NUM> to be mounted directly to a manifold.

Pressures from the barrier diaphragms <NUM> and <NUM> are transmitted to the sensor <NUM> via a fill fluid that travels through various passages <NUM>. The fill fluid could denote an incompressible fluid, so pressure applied by the barrier diaphragm <NUM> or <NUM> is conveyed by the fill fluid to the sensor <NUM>. The fill fluid denotes any suitable fluid for conveying pressure, such as silicone oil or other suitable fluid. Each passage <NUM> denotes any suitable passageway for fill fluid.

The pressure sensor <NUM> may optionally contain fluid expansion compensation elements 214a-214b, which are used to reduce the thermal expansion effect of the fill fluid. In some embodiments, it may be necessary or desirable to reduce or minimize the fluid travel of the fill fluid through the passages <NUM>. However, this may be complicated by the need to operate the pressure sensor <NUM> over a large temperature range. Since the fluid expansion properties of the fill fluid may greatly exceed those of the body <NUM>, this results in a larger volume of fluid as the temperature increases. To help handle this issue, the fluid expansion compensation elements 214a-214b can be used and denote cylindrical or other components that encircle or surround various ones of the passages <NUM>. The fluid expansion compensation elements 214a-214b can be formed using a low thermal expansion material, such as INVAR (FeNi36 or 64FeNi) or other material with low thermal expansion as compared to the material of the coplanar body <NUM>.

Each barrier diaphragm <NUM> and <NUM> has an associated overload or overpressure protection mechanism <NUM> and <NUM>, respectively. The protection mechanisms <NUM> and <NUM> generally provide protection against overpressure conditions that can damage the pressure sensor <NUM>. Here, the protection mechanisms <NUM> and <NUM> implement separate protection for the sensor <NUM>. Each of the protection mechanisms <NUM> and <NUM> includes any suitable structure for providing structural reinforcement and overpressure protection. Each of the protection mechanisms <NUM> and <NUM> could, for instance, denote an overload diaphragm that can move, where the associated barrier diaphragm <NUM> or <NUM> can nest against the protection mechanism <NUM> or <NUM> to prevent further movement of the barrier diaphragm <NUM> or <NUM>.

As described in more detail below, the pressure sensor <NUM> includes unique flow paths (such as the passages <NUM>) that are used by the fill fluid to transfer process pressure to the sensor <NUM>. These flow paths also allow the pressure sensor <NUM> to comply with suitable flame-proof requirements.

Although <FIG> illustrates one example of a pressure sensor <NUM>, various changes may be made to <FIG>. For example, the sizes, shapes, and relative dimensions of the components in <FIG> are for illustration only. Also, other arrangements of the components in <FIG> could be used in a pressure sensor. In addition, the overall form factor for the pressure sensor <NUM> could vary as needed or desired, and the features used to comply with flame-proof requirements described in this patent document could be used in other pressure sensors (including non-differential pressure sensors).

<FIG> illustrates example operation of a pressure sensor according to this disclosure. For ease of explanation, the operations shown in <FIG> are described with respect to the differential pressure sensor <NUM> of <FIG>. However, these operations could occur using any other suitable pressure sensor.

As shown in <FIG>, internal porting is implemented in the body <NUM> using the passages <NUM> to transfer two pressure inputs to the sensor <NUM>. A high-pressure port <NUM> provides a higher-pressure input to the sensor <NUM>, and a low-pressure port <NUM> provides a lower-pressure input to the sensor <NUM>.

A fill fluid <NUM> fills a gap between the barrier diaphragm <NUM> and the protection mechanism (overload diaphragm) <NUM>. The fill fluid <NUM> is ported via the port <NUM> to both the high-pressure side of the sensor <NUM> and to a gap between the body <NUM> and the other protection mechanism (overload diaphragm) <NUM>. Similarly, a fill fluid <NUM> fills the gap between the barrier diaphragm <NUM> and the protection mechanism (overload diaphragm) <NUM>. The fill fluid <NUM> is ported via the port <NUM> to both the low-pressure side of the sensor <NUM> and to a gap between the body <NUM> and the other protection mechanism (overload diaphragm) <NUM>.

During the application of high-side pressure, the pressure is transmitted from the barrier diaphragm <NUM> to the fill fluid <NUM> and then to the sensor <NUM> and to the gap between the other protection mechanism (overload diaphragm) <NUM> and the body <NUM>. This causes the protection mechanism <NUM> to deflect away from the body <NUM>, increasing the gap between the body <NUM> and the protection mechanism <NUM>. Meanwhile, the gap between the barrier diaphragm <NUM> and the protection mechanism <NUM> is reduced. When sufficient fill fluid <NUM> has moved to eliminate the gap between the barrier diaphragm <NUM> and the protection mechanism <NUM>, the barrier diaphragm <NUM> and the protection mechanism <NUM> nest together, and no additional pressure will be transmitted to the sensor <NUM>, thus providing overpressure protection for the sensor <NUM>.

In a similar manner, during the application of low-side pressure, the pressure is transmitted from the barrier diaphragm <NUM> to the fill fluid <NUM> and then to the sensor <NUM> and to the gap between the other protection mechanism (overload diaphragm) <NUM> and the body <NUM>. This causes the protection mechanism <NUM> to deflect away from the body <NUM>, increasing the gap between the body <NUM> and the protection mechanism <NUM>. Meanwhile, the gap between the barrier diaphragm <NUM> and the protection mechanism <NUM> is reduced. When sufficient fill fluid <NUM> has moved to eliminate the gap between the barrier diaphragm <NUM> and the protection mechanism <NUM>, the barrier diaphragm <NUM> and the protection mechanism <NUM> nest together, and no additional pressure will be transmitted to the sensor <NUM>, thus providing overpressure protection for the sensor <NUM>.

Although <FIG> illustrates one example of operation of a differential pressure sensor with overpressure protection, various changes may be made to <FIG>. For example, the sizes, shapes, and relative dimensions of the components in <FIG> are for illustration only.

<FIG> illustrates a flow porting with an integral flame-proof safety mechanism in a pressure sensor <NUM> according to the claimed invention. For ease of explanation, the flow porting shown in <FIG> is described with respect to the pressure sensor <NUM> of <FIG>. However, the flow porting could be used with any other suitable pressure sensor.

In some embodiments, to help increase or maximize the accuracy of the pressure sensor <NUM>, the volume of the fill fluid used in the body <NUM> can be minimized. As a result, internal flow paths (the passages <NUM> implementing the pressure ports <NUM> and <NUM>) in the pressure sensor <NUM> have relatively small diameters and may contain a number of bends and curves.

As shown in <FIG>, the body <NUM> includes a number of narrow passages for the fill fluid, at least some of which are curved or include bends. The passages include one or more passages <NUM> that are generally straight but that are long and narrow, so these passages <NUM> have relatively small cross-sections relative to their lengths. The passages also include narrow helical passages 404a-404b, where the curved or helical passage 404a is longer than the curved or helical passage 404b. The helical passages 404a-404b may be curved along substantially their entire lengths, and again the helical passages 404a-404b have relatively small cross-sections relative to their lengths. In addition, some of the passages include a number of sharp bends 406a-406d, such as <NUM>° turns.

Long and narrow passages with turns or bends are well-suited for arresting flames. This is because of (i) the large surface area relative to the volumetric flow path in a narrow and long passage and (ii) the turbulence generated in curved passages and <NUM>° turns. These features are very effective at absorbing thermal energy in a flame front and extinguishing a flame.

Thus, flame arresting can be accomplished in the pressure sensor <NUM> using the long and narrow flow paths (at least some with curved passages and <NUM>° turns) that serve "double duty," minimizing internal fill fluid volume and providing flame-proof functionality. The pressure sensor <NUM> can therefore inherently comply with flame-proof requirements without the need for incorporating flame arrestors or other components that add cost and increase the overall package size of the body <NUM>.

Although <FIG> illustrates a flow porting with an integral flame-proof safety mechanism in a pressure sensor, various changes may be made to <FIG>. For example, the sizes, shapes, and relative dimensions of the components in <FIG> are for illustration only.

<FIG> illustrates an example use of a pressure sensor according to this disclosure. For ease of explanation, the use shown in <FIG> is described with respect to the pressure sensor <NUM> of <FIG>. However, the pressure sensor <NUM> could be used in any other suitable manner.

As shown in <FIG>, the pressure sensor <NUM> is mounted directly to a manifold <NUM>. The manifold <NUM> denotes any suitable structure that is configured to transport at least one process fluid <NUM>. As noted above, the manifold <NUM> could be configured to transport one or more corrosive process fluids at high pressures. The manifold <NUM> could have any suitable size, shape, and dimensions and could be formed from any suitable material(s).

The pressure sensor <NUM> can be mounted directly to openings <NUM> of the manifold <NUM>. The openings <NUM> could have any suitable size, shape, and dimensions and could be separated by any suitable distance. As noted above, for example, the manifold <NUM> could denote an industry-standard DIN manifold, and the barrier diaphragms <NUM> and <NUM> can be small enough and spaced apart to fit within the established bolt pattern for the DIN manifold.

Although <FIG> illustrates one example use of a pressure sensor <NUM>, various changes may be made to <FIG>. For example, the pressure sensor <NUM> could be used in any other suitable manner and need not be used with a manifold.

<FIG> illustrates an example method <NUM> for pressure sensing using a pressure sensor having flow porting with integral flame-proof safety according to this disclosure. For ease of explanation, the method <NUM> shown in <FIG> is described with respect to the pressure sensor <NUM> of <FIG> having the internal flow porting as shown in <FIG>. However, the method <NUM> could be used with any other suitable pressure sensor.

As shown in <FIG>, one or more input pressures are received at step <NUM>. This could include, for example, receiving input pressures at the barrier diaphragms <NUM> and <NUM> of the pressure sensor <NUM>. As a particular example, this could include receiving input pressures at the barrier diaphragms <NUM> and <NUM> of the pressure sensor <NUM> through openings <NUM> of the manifold <NUM>. The one or more input pressures are transferred to fill fluid at step <NUM>. This could include, for example, the barrier diaphragms <NUM> and <NUM> transferring the input pressures to incompressible fill fluid <NUM> and <NUM>.

The one or more input pressures are transported through various fluid passages at step <NUM>. This could include, for example, the fill fluid <NUM> and <NUM> transporting the input pressures through the pressure ports <NUM> and <NUM>, which include the passages <NUM>, <NUM> and the passages with the bends 406a-406d. At least some of the fluid passages extend between the barrier diaphragms <NUM> and <NUM> and the sensor(s) <NUM>, and some of the fluid passages could extend between the barrier diaphragms <NUM> and <NUM> to provide overpressure protection as shown in <FIG>. Because of the long and narrow design of the fluid passages, as well as the curved or bent design of at least some of the fluid passages, the fluid passages provide an integral flame-proof safety mechanism in the pressure sensor <NUM>.

The one or more input pressures are conveyed to one or more pressure sensors at step <NUM>, and one or more pressure measurements are generated at step <NUM>. This could include, for example, the at least one sensor <NUM> receiving the input pressure(s) from the fill fluid <NUM> and <NUM>. This could also include the at least one sensor <NUM> generating an electrical signal whose voltage or current varies proportionally with the input pressure(s). This could further include different sensors <NUM> generating multiple pressure measurements, such as differential and static pressure measurements.

Although <FIG> illustrates one example of a method <NUM> for pressure sensing using a pressure sensor having flow porting with integral flame-proof safety, various changes may be made to <FIG>. For example, while shown as a series of steps, various steps in <FIG> could overlap, occur in parallel, occur in a different order, or occur any number of times.

It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The phrase "associated with," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like.

The description in the present application should not be read as implying that any particular element, step, or function is an essential or critical element that must be included in the claim scope. The scope of patented subject matter is defined only by the allowed claims.

Claim 1:
An apparatus comprising:
a sensor body (<NUM>) including a low-pressure side and a high-pressure side;
a sensor (<NUM>) disposed between the low-pressure side and the high-pressure side and configured to measure pressure;
at least one pressure input per each of the low-pressure side and the high-pressure side of the sensor body, in or on the sensor body, the at least one pressure input configured to provide at least one input pressure from at least one of the low-pressure side and the high-pressure side to the sensor; and
multiple fluid passages (<NUM>, <NUM>, <NUM>, <NUM>, 404a-404b, 406a-406d) configured to convey the at least one input pressure from the at least one pressure input from each of the low-pressure side and the high-pressure side to the sensor using a fill fluid (<NUM>, <NUM>);
wherein the fluid passages comprise:
one or more long and narrow straight passages (<NUM>);
and
wherein the multiple fluid passages are configured to both (i) transport the fill fluid and (ii) absorb thermal energy in a flame created by the sensor before the flame exits the sensor body;
characterized in that:
the fluid passages also include long and narrow helical passages (404a, 404b), wherein one of the helical passages (404a) is longer than a further (404b) of the helical passages.