Patent ID: 12253100

Where applicable, like reference characters designate identical or corresponding components and units throughout the several views, which are not to scale unless otherwise indicated. The embodiments disclosed herein may include elements that appear in one or more of the several views or in combinations of the several views. Moreover, methods are exemplary only and may be modified by, for example, reordering, adding, removing, and/or altering the individual stages.

The drawings and any description herein use examples to disclose the invention. These examples include the best mode and enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. An element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or functions, unless such exclusion is explicitly recited. References to “one embodiment” or “one implementation” should not be interpreted as excluding the existence of additional embodiments or implementations that also incorporate the recited features.

DESCRIPTION

The discussion now turns to describe features of the embodiments shown in drawings noted above. The embodiments here improve on the design of conventional relays or “amplifiers” that use fixed orifices to bleed actuating media at steady state. The fixed orifice addresses control issues that occur due to a non-linearity in performance of certain valves found in these amplifiers. This non-linearity or “dead zone” may delay response of amplifiers to increases in a supply signal from steady state. Maintaining a steady bleed through the fixed orifice outfits amplifiers to provide precise and stable control of any corresponding flow control. The proposed design not only maintains this level of control, but it also eliminates bleed of actuating media from the amplifier to atmosphere at steady state (or when there is no valve travel). Other embodiments are within the scope of this disclosure.

FIG.1depicts an example of a pneumatic relay100. This example is found at a distribution network102, typically designed to carry material104through a network of conduit106. The relay100may be part of a flow control108that has a valve body110to connect in-line with the conduit106. The valve body110may house a seat112and a closure member114, which can move to positions relative to the seat112to regulate flow of material104. The flow control108can manage the positions of the closure member114with an actuator116. A controller118connects with the actuator116. The controller118may have operating hardware120that connects to the relay100. The operating hardware120may convert an incoming pneumatic supply signal S1into an amplifier input signal S2that operates a variable orifice122in the relay100to regulate flow of an actuator control signal S3.

Broadly, the pneumatic relay100may be configured to avoid bleed to atmosphere. These configurations may embody devices that raise pressure or volume flow of an input signal, preferably by some linearly proportional amount. The devices include relays, as well as “amplifiers” or “boosters.” These devices find use in flow control systems that are resident at or in proximity to a pneumatically-actuated valve.

The distribution system102may be configured to deliver or move resources. These configurations may embody vast infrastructure. Material104may comprise gases, liquids, solids, or mixes, as well. The conduit106may include pipes or pipelines, often that connect to pumps, boilers, and the like. The pipes may also connect to tanks or reservoirs. In many facilities, this equipment forms complex networks.

The flow control108may be configured to regulate flow of material104through the conduit106in these complex networks. These configurations may include control valves and like devices. The valve body110in such devices is often made of cast or machined metals. This structure may form a flange at the openings I, O. Adjacent pipes106may connect to these flanges to allow material104to flow through the device, for example, through an opening in the seat112. The closure member114may embody a metal disc or metal “plug.” The actuator116may use pneumatics or hydraulics to regulate the position of the plug114, which in turn manages flow of material104through the seat112into the pipes106downstream of the device.

The controller118may be configured to process and generate signals. These configurations may connect to a control network (or “distributed control system” or “DCS”), which maintains operation of all devices on process lines to ensure that materials flow in accordance with a process. The DCS may generate control signals with operating parameters that describe or define operation of the control valve108for this purpose. The operating hardware120may employ electrical and computing components (e.g., processors, memory, executable instructions, etc.). These components may also include electro-pneumatic devices that operate on incoming pneumatic supply signal S1. These components ensure that the outgoing actuator control signal S3to the actuator116is appropriate for the control valve108to supply material104downstream according to process parameters.

The variable orifice122may be configured for precise control of the actuator control signal S3. These configurations may include devices that incorporate valves that operate in response to changes in flow of actuating media, including the amplifier input signal S2. At steady state, these valves may prevent flow or “bleed” of actuating media, thus eliminating a source of waste, both in terms of cost to operate pumps or compressors at the facility that pressurize incoming pneumatic supply signal S1or emission of potential greenhouse gasses to atmosphere.

FIG.2depicts an example of the pneumatic relay100ofFIG.1. The variable orifice122may include a main flow control124that controls flow out of the relay100to the actuator116(as the actuator control signal S3). The main flow control124may include a pair of “main” valves that operate as a supply valve V1and a vent valve V2. The device may also include a “bleed” valve V3. In one implementation, the valves V1, V2, V3are closed at steady state to prevent changes in the actuator control signal S3to the actuator116that would, for example, correspond with movement or travel of the flow control108. The vent valve V1opens in response to a decrease in the amplifier input signal S2. This response allows material to vent from actuator116via the relay100. On the other hand, the bleed valve V3opens first in response to an increase in the amplifier input signal S2. This response may cause a (slight) increase in the actuator control signal S3to the actuator116. As the amplifier input signal S2increases, the bleed valve V3will continue to open until it reaches its fully-opened state. The supply valve V1then opens in response to further increases in the amplifier input signal S2.

FIG.3depicts a plot of exemplary performance for the example relay100ofFIG.2. The plot includes performance curves (P1, P2) that describe exemplary operation for both the proposed design of the relay100(that does not bleed actuating media at steady state SS) and conventional designs (that bleed actuating media through a fixed orifice at steady state SS), respectively. Both designs exhibit a “main” dead zone D1, where an increase in the amplifier input signal S2does not result in any change in the actuator control signal S3. The dead zone D1corresponds with response of the main valve that is found in the proposed design (e.g., supply valve V2) and in the fixed-orifice, conventional design. Use of the bleed valve V3also introduces a small dead zone D2into the performance curve P1. However, the tradeoff for this nearly negligible change in performance (at the dead zone D2) is outweighed significantly by the benefits of having the relay100effectively not bleed any amplifier input signal S2at steady state SS. The relay100is comparatively much more energy efficient and environmentally friendly, and performs just as well to control of the actuator116around steady state SS.

FIG.4depicts an elevation view of the cross-section of exemplary structure for use in the relay100ofFIG.2. The main flow control124may include a vent plug126with an elongate body128that changes in diameter along its length. These changes may form shoulders130. On one end, the elongate body128may form a seat contact surface132. The other end of the elongate body128may have a threaded end134. A supply plug136may include a central bore138that receives the elongate body128. Changes in diameter of the central bore138may form several shoulders140. At one end, the supply plug136may have a seat contact surface142. Its other end may have a recess144. In one implementation, a bleed plug146may reside in the recess144. The bleed plug146may have a central bore148, for example, with threads T to allow it to screw onto an exposed portion of threaded end134of the vent plug126. The bleed plug146may have a seat contact surface150. A nut152or like threaded implement may lock the bleed plug144onto the elongate body128, preferably to prevent it from backing off of the threaded end134. The device may also include a first spring154that interposes between the vent plug126and the supply plug136.

FIG.5depicts an elevation view of the cross-section of the relay100ofFIG.4with additional details for an implementation of the device. This example includes a vent seat156with an aperture158. The device may also include a supply seat160. This component may have a central aperture162and a supply aperture164, often disposed about the periphery or circumferences of the supply seat160. The design may also require a second spring166that interposes between the supply plug136and a surface of an end cap168. This construction prevents bleed of the incoming pneumatic supply signal S1at steady state because the seat contact surface150of the bleed plug146stays in contact with a surface of the recess144, the seat contact surface142of the supply plug136stays in contact with a surface of the supply seat158, and the seat contact surface132of the vent plug126stays in contact with a surface of the vent seat156. As a result, this arrangement maintains parameters of the actuator control signal S3to the actuator116at steady state.

FIG.6also depicts the cross-section ofFIG.5. The relay100may include a housing, shown generally in the diagram as172. An opening174in the housing172may allow the amplifier input signal S2to impinge on a diaphragm assembly176. A spring178may interpose between the vent seat156and the supply seat160. In this example, an increase in the amplifier input signal S2, will first cause the bleed plug146to open (relative to its contact position in the recess144) as it overcomes the spring force of the first spring154. This feature will increase actuator control signal S3that exists the relay100. Any further increase in the amplifier input signal S2will open the supply plug136(relative to its contact position in the supply seat160), which further increases the actuator control signal S3.

FIG.7depicts a perspective view of an example of the controller118in exploded form. This structure may include a manifold having a manifold body180, typically machined or formed metal, plastic or composite. The device may include one or more boards182with processing hardware disposed thereon. Other hardware may include a current-to-pressure converter184, which along with the relay100can generate the actuator control signal S3(for example, instrument air) to the actuator116. As also shown, the controller100may have hardware to protect the control components. This hardware may include an enclosure, shown as covers C1, C2in this example. The covers C1, C2may secure to the manifold body182to protect the control components from conditions that prevail in the environment surrounding the flow control108. One of the covers C2may incorporate a display186and a pushbutton input device188that may operate as the primary local user interface to allow an end user (e.g., technician) to interact with the controller100. This feature may be important for regular maintenance, configuration, and setup, for example, to allow the end user to exit from valve operating mode and step through a menu structure to manually perform functions such as calibration, configuration, and monitoring. In one implementation, the controller118may further include one or more gauges G1, G2that can provide an indication of the flow conditions (e.g., pressure, flow rate, etc.) of the fluid that the controller100uses to operate the flow control108.

FIG.8depicts a perspective view of exemplary structure for the flow control108. The valve body110may form a flow path190with flanged, open ends192. The controller118may fasten to a bracket194that is part of the flow control108. Fasteners such as bolts are useful for this purpose. Valve components like the seat and the closure member may reside inside of the body110(and, thus, are hidden in the present view). The device may include a valve stem196that connects the closure member with the actuator116. In one implementation, the actuator116may include a bulbous housing198, typically with two pieces that clamp about the edges to entrap a diaphragm (not shown) round the periphery. As noted herein, the actuator control signal S3may pressurize an upper portion of the housing198that acts on one side of the diaphragm. An actuator spring in the lower portion of the housing198acts on the opposite side of the diaphragm. This construction affects the position of the closure member to regulate flow through the valve body110.

In view of the foregoing, the improvements here effectively eliminate bleed of actuating media from amplifiers. The embodiments incorporate a variable orifice, described herein as a small bleed valve; however, other device structures may achieve similar results as well. Use of the variable orifice in place of a fixed orifice prevents flow of actuating media at steady state. This feature saves energy and avoids unnecessary emissions. It does not, however, sacrifice any control over the corresponding actuator and, thus, flow controls that adapt amplifiers of the proposed design can still maintain precise control over flow into a process line.

Examples appear below that include certain elements or clauses one or more of which may be combined with other elements and clauses to describe embodiments contemplated within the scope and spirit of this disclosure. The scope may include and contemplate other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.