Abstract:
An output device for a pressure transducer incorporates a cable connector and an electronic display. Both may be selectably positioned relative to the pressure transducer. In one aspect of the invention, the electronic display is rotatable around an axis perpendicular to the plane of the display. In another aspect of the invention, the cable connector is positioned by adjusting the connection of the output device relative to the pressure transducer. In some embodiments, the adjustability of the output device is provided through a bayonet connection between the output device and the pressure transducer. The adjustments to position of the display and of the cable connector may be performed without the use of tools. An output device constructed in accordance with the present invention may be field-configured in a multitude of ways, largely eliminating the need for the preselection of particular output devices for particular installations.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to pressure transducers and specifically to output devices for pressure transducers. 
     BACKGROUND OF THE INVENTION 
     Pressure transducers are used for measuring the pressure of a fluid in a device or system. Pressure transducers may typically provide two types of outputs—(1) a cable connection for transmitting a signal representative of the sensed pressure to a remote monitoring or control device and (2) a human-readable display for providing a local reading of the sensed pressure. 
     Installation requirements for pressure transducers in the field may impose particular space or configuration requirements on the design of output devices for the pressure transducers. One use of a pressure transducer is to measure the pressure of a gas line. A pressure transducer is typically connected to a gas line such that it is perpendicular to the gas line. The connection between the pressure transducer and the gas line typically includes a passage for the fluid whose pressure is being measured, with a valve to an inlet to a sensing chamber in the transducer. When a pressure transducer is installed on a gas line, it is generally preferable that the passage provided in the connection be positioned so that it is parallel to the direction of flow in the gas line to avoid interruption of the flow. Accordingly, the position of the gas line will dictate the orientation of the pressure transducer. In many applications there are similar constraints on where a pressure transducer may be installed and how it may be positioned. 
     It is important that the cable connector and/or the display provided for output from a pressure transducer be accessible under various installation conditions. A local display should be oriented so that it is convenient and easy to read. A cable connector should be oriented so that it can easily be connected to the appropriate cable. When a pressure transducer is installed in the field, one or more sides of the pressure transducer may be obscured or obstructed, requiring the outputs to have particular orientations in order to be accessible. Limited vantage points might be available for viewing a display. In addition, under certain circumstances, a display having a particular orientation or a cable connector facing in a particular orientation may be especially desirable. It may be important for a number of displays to be aligned, for example, to form a “bank” of displays by positioning several transducers and their associated displays together on a set of gas lines. Given these requirements, pressure transducers having different configurations of cable connectors and local displays, particularly relative to the fluid passage of the pressure transducer, are generally needed for different applications. To satisfy this need, manufacturers have typically provided each type of transducer in several different configurations, each configuration having a unique placement, or orientation, of the display. However, carrying inventory for multiple configurations of the same transducer is expensive. 
     A measuring indicator device for a pressure transducer is disclosed in U.S. Pat. No. 6,119,524, entitled “Measuring Indicator Device,” issued Sep. 19, 2000, to Kobold. The display disclosed in the &#39;524 patent is screwed onto a casing. A pressure transducer and a line socket are connected on opposite sides of the casing. The casing is rotatable around its longitudinal axis. The position of the display can be adjusted by rotating the casing. Although the position of the display disclosed in the &#39;524 patent may be adjusted, the disclosed design does not eliminate the need for providing multiple configurations of the same transducer. For example, FIGS. 1 and 2 of the &#39;524 patent show two such configurations in which the display has been screwed into the casing at two different orientations which are rotated ninety degrees from one another. 
     An adaptable, easily adjustable output device for pressure transducers is needed. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an adjustable output device for pressure transducers and a method for installing and adjusting the output device. An output device constructed in accordance with the present invention may be field-configured in a multitude of ways, largely eliminating the need for preselecting particular output devices for particular installations. An output device constructed in accordance with the invention incorporates a cable connector and an electronic display. In one aspect of the invention, both the cable connector and the electronic display can be selectably positioned relative to the pressure transducer. 
     In one aspect of the invention, the orientation of the electronic display relative to the cable connector is adjustable. The electronic display is adjustable such that the digits of the display can generally be viewed right-side up or in the orientation most convenient to the user, given the constraints of a particular installation. The electronic display is rotatable around an axis perpendicular to the plane of the display. In some embodiments of the invention, the output device is substantially cylindrical in form. One end of the output device connects to a pressure transducer. The electronic display is disposed on the opposite end of the output device. In some embodiments, the display is disposed transverse to the longitudinal axis of the output device so that it can be seen from above, e.g., by forming an endcap for a generally cylindrical output device. The display can be rotated around the longitudinal axis of the output device in some embodiments. The orientation of the display can be adjusted without the use of tools and without taking apart the device or removing mechanical fasteners such as screws. 
     In another aspect of the invention, the orientation of the cable connector relative to the pressure transducer is adjustable. In one aspect of the invention, the output device may connect to the pressure transducer in a number of orientations. The orientation of the output device relative to the pressure transducer selects the orientation of the cable connector. In some embodiments, the cable connector is positioned on the side of the output device. The position of the output device may be changed without the use of tools. In some embodiments, the adjustability of the output device is provided through a bayonet connection between the output device and the pressure transducer. 
     These and other features and advantages of the present invention will become readily apparent from the following detailed description, wherein embodiments of the invention are shown and described by way of illustration of the best mode of the invention. As will be realized, the invention is capable of other and different embodiments and its several details may be capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not in a restrictive or limiting sense, with the scope of the application being indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and objects of the present invention, reference should be made to the following detailed description taken in connection with the accompanying drawings, wherein: 
     FIG. 1 is a side view of a pressure transducer assembly including an output device constructed in accordance with one embodiment of the invention; 
     FIG. 2 is a side view of the pressure transducer assembly of FIG. 1; 
     FIG. 3 is a side view of the output device of FIG. 1; 
     FIG. 4 is a top view of the output device of FIG. 3; and 
     FIG. 5 is a cross-sectional view of the output device of FIG. 3, taken along the lines A—A indicated in FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show one example of an output device  30  constructed according to the invention. As shown, output device  30  is coupled to a pressure transducer  20 . Transducer  20  and output device  30  form at least part of a transducer assembly  10 . The output device  30  is designed to provide a conveniently adjustable output mechanism for pressure transducer  20  that is usable in a range of installation situations. Output device  30  includes a housing  31 , an electronic display  40 , and a cable connector  50 . An electrical signal representing the pressure measurement taken by the pressure transducer  20  is provided through the output device  30  for local display on electronic display  40  and for remote use through cable connector  50 . The output device  30  allows both the orientation of the cable connector  50  relative to the pressure transducer  20  and the orientation of the electronic display  40  to be adjusted. 
     The electronic display  40  is rotatably connected to the housing  31  so that the display  40  can be rotated relative to housing  31  about an axis perpendicular to the plane of the display  40 . Preferably, the two types of outputs  40 ,  50  provided through the output device  30  both have a range of positions and may be adjusted independently, allowing a virtually infinite number of configurations to be implemented using the output device of the present invention. 
     In certain embodiments, the basic shape of the output device  30  is designed to match the dimensions and form of the pressure transducer  20 . The pressure transducer  20  may be cylindrical in form, as illustrated in FIGS. 1 and 2. FIGS. 3,  4  and  5  are illustrations of the output device  30 , shown detached from the pressure transducer  20 . In the illustrated embodiment, the output device  30  is also substantially cylindrical in form. Housing  31  has a first end  33 , a sidewall  34  and a second end  35 , and housing  31  extends along a longitudinal axis  32 . 
     In the illustrated embodiment, the electronic display  40  is mounted on one end of the housing  31 . The cable connector  50  is mounted on the sidewall  34 . On its other end  35 , the housing  31  connects to the pressure transducer  20  with a pressure transducer connection  60 . In the illustrated embodiment, the output device  30  attaches to the top of a pressure transducer  20 , on the end opposite to the pressure transducer&#39;s fluid inlet, such that the output device  30  and pressure transducer  20  are coaxial along the longitudinal axis  32 . The circular cross-sections of the output device  20  and the pressure transducer  20  may have substantially the same dimensions. This arrangement allows the entire pressure transducer assembly  10  to have a compact and integrated profile. 
     In the illustrated embodiment, the electronic display  40  is provided on the end  33  of the housing  31  that is opposite to the pressure transducer connection  60 , such that it forms an endcap for the top of the output device  30 . The display  40  is substantially planar and is disposed so that it is transverse to the longitudinal axis  32 . In particular, in the illustrated embodiment, the display is disposed so that it is perpendicular to the longitudinal axis  32  of the housing  31 . The positioning of the display  40  allows it to be viewed from above the pressure transducer assembly  10 , e.g., looking toward the output device along the longitudinal axis  32  of the housing  31 . This is especially convenient when the installation of the pressure transducer assembly is underground, low to the ground, or obscured from the side. The display  40  is disposed so that it may be rotated relative to the housing  31  around an axis perpendicular to the face of the display  40 . In the illustrated embodiment, the display  40  is perpendicular to the longitudinal axis  32  of the housing  31  and can be rotated around the longitudinal axis  32 . The rotatability of the display  40  allows the display  40  to be adjusted so that it may be read in the desired or most convenient orientation. One advantage is a reduction in the risk of human error in reading the displayed pressure measurement. 
     The face of the display  40  in accordance with some embodiments of the invention is shown in FIG.  4 . In the illustrated embodiment, the top of the housing  31  includes a bezel  44  with the electronic display  40  disposed in the bezel  44 . In some embodiments, the display  40  can be rotated up to about 360 degrees around the axis  32 . The display  40  may be rotatable continuously or in small increments through its range of rotation. In some embodiments, the display  40  may be adjusted by holding the bezel  44  and rotating it, without the use of tools. The bezel  44  may have a textured, e.g., ridged, surface to allow for ease of gripping for rotating the bezel. Since the display  40  is rotatable with respect to housing  31 , the orientation of display  40  may be adjusted without manipulating the connection of the output device  30  to the pressure transducer  20 . 
     As noted above, display  40  is rotatably coupled to housing  31 . That rotatable coupling may be provided using a variety of mechanisms, such as friction connections, grip ring, or ratchet-type connections. A single mechanism can provide both attachment of the display  40  to the housing  31  and rotation of the display  40 . As may be seen in the cross-sectional view of FIG. 5, in some embodiments, the upper portion of the housing  31  may form a detachable electronic display unit  42 . The electronic display unit  42  incorporates the electronic display  40 , the bezel  44 , and a display electronics assembly housing  46  for a display electronics assembly  47  that generates and controls the electronic display  40 . In the illustrated embodiment, the electronic display unit  42  has a grip ring  48  at its base. The grip ring  48  is friction fitted to the inner sidewall  37  of the main portion of the housing  31 . The grip ring  48  frictionally couples the electronic display unit  42  to the main portion of the housing  31  and permits the unit  42  to be rotated relative to housing  31  about the longitudinal axis  32 . A detent disposed on the inner sidewall  37  of the housing  31  can prevent hyperrotation of the display  40  to avoid, for example, twisting the wires that connect to the display electronics assembly  47  sufficiently to damage the wires or break one of their electrical connections. The electronic display unit  42  may be replaced by a blank endcap if a local display is not desired for a particular installation. 
     The electrical connections inside the output device can be seen in the cross-section of FIG.  5 . The electronic display  40  may be any type of electronic display, such as an LCD display or an LED display, including a loop-controlled or a voltage-controlled LED display. The display electronics assembly  47  receives a signal representative of the sensed pressure from the pressure transducer through wires  49  and generates the reading seen in the electronic display  40 . The display electronics assembly  47  may include a microprocessor and may allow for calibration, and other adjustments, such as the units of measurement used in the display, of the electronic display  40 . The electronic display  40  may include a control panel to allow for field adjustment of the electronic display  40 . 
     In the illustrated embodiment, the cable connector  50  is mounted to the sidewall  34  of the housing  31 . Although, in the illustrated embodiment, cable connector  50  is a sub-D connector, any desired type of cable connector  50 , standard or custom-designed, may be used. The position of the cable connector  50  relative to the pressure transducer can be adjusted by rotating the housing  31  around the longitudinal axis  32  relative to the pressure transducer  20  so that the cable connector  50  has the desired direction. 
     In certain embodiments, the housing  31  of the output device  30  is dimensioned both to match the dimensions of the pressure transducer and to accommodate the cable connector  50  in the desired orientation. Cable connector  50  includes a face  52  and a mounting plate  54 . The cable connector  50  may be mounted so that the face  52  of the connector  50  does not protrude from the sidewall  34  of the housing  31 . In the illustrated embodiment, the cable connector  50  is mounted in a recess  36  in the sidewall  34  of the housing  31  to preserve the substantially cylindrical and compact shape of the housing  3   1 . The recess  36  is built into the housing  31  to accommodate the depth  56  of the cable connector  50  and has a flat back wall for attachment of the mounting plate  54  of the cable connector  50 . Although the cable connector  50  could be affixed to the housing  31  in a number of orientations, the cable connector  50  is preferably oriented with its longest dimension either along the longitudinal axis (a vertical orientation) or perpendicular to the longitudinal axis (a horizontal orientation). The longest dimension of the illustrated cable connector  50  is its width  55 . Attaching the cable connector  50  in a vertical orientation may disadvantageously require the length of the output device  30  along the axis  32  to be extended. The cable connector  50  shown is mounted with a horizontal orientation. However, in the illustrated embodiment, because the housing  31  is dimensioned to match the pressure transducer  30 , the diameter  39  of the housing  31  is not wide enough to accommodate the width  55  of the cable connector  50 . Accordingly, two protrusions  38  extend from the sidewall  34  of the housing  31 , adjacent to the back wall of the recess  36 , to support the mounting plate  54  of the cable connector  50  without substantially altering the cylindrical profile of the housing  31 , as can be seen in FIGS. 2 and 3. Depending on the characteristics of the connector used for particular embodiments, the housing  31  may be appropriately dimensioned to provide the desired positioning for the connector. The cable connector  50  may be attached to the housing  31  by mechanical or adhesive means, for example, screws or glue. An aperture is provided in the recess  36  of the housing  31  to allow for electrical wires or leads to attach to the back of the cable connector  50  inside the housing  31 . In the illustrated embodiment, the cable connector  50  receives a signal representative of the sensed pressure from the pressure transducer through wires  59 , which can be seen in FIG.  5 . The wires  49 ,  59  to the display electronics assembly  47  and to the cable connector  50  may also be used, for example, to supply power and send and receive other signals, which may, for example, be generated by front end electronics, from the pressure transducer  20 . 
     In some embodiments, the housing  31  selectably and detachably connects to pressure transducer  20  at its bottom end  35 . As shown in FIG. 3, the end  35  may be implemented as a bayonet type connector  60 , which defines one or more slots  62  for facilitating a bayonet connection between end  35  and transducer  20 . In such embodiments, posts in transducer  20  (not shown) engage slots  62  in a known fashion to selectably couple or release output device  30  and transducer  20 . In the illustrated embodiment, bayonet connector  60  defines four slots  62  (only one of which is shown in FIG. 3) and the slots are evenly spaced apart from one another (or spaced at 90 degree intervals) around end  35 . In this embodiment, the output device  30  may be connected to transducer  20  in any one of four different orientations (i.e., each of the orientations being rotated by 90 degrees from another one of the possible orientations). 
     In this embodiment, the orientation of cable connector  50  with respect to transducer  20  may be selected simply by coupling the posts of transducer  20  into the appropriate slots  62  of bayonet connector  60 . If it is desired, for example, to rotate the position of cable connector  50  by ninety degrees, the output connector  30  may simply be detached from transducer  20 , rotated ninety degrees, and then reattached via the bayonet connector. It will be appreciated that additional flexibility in selecting the orientation of cable connector  50  may be provided if desired by adding additional slots  62  to bayonet connector  60  (e.g., six slots may be provided with all slots being spaced apart by sixty degrees). The bayonet connection is readily field-adjustable without the use of tools. Once the cable connector  50  has been located in a desired orientation, the electronic display  40  can be independently adjusted, or rotated, to obtain the desired orientation. 
     The illustrated embodiment provides two-degrees of freedom for adjusting the configuration of an output device for a pressure transducer. Because both the cable connector  50  and the local display  40  are readily adjustable, the output device  30  may be readily adapted to a multitude of installation situations. 
     An output device constructed in accordance with the present invention may be combined with pressure transducers of any type. The display may be disposed so that it is transverse but not perpendicular to the longitudinal axis of the output device. Although the illustrated embodiment incorporates and is designed to accommodate a sub-D cable connector, embodiments of the present invention could also be constructed using any type of cable connector. Other types of connections, including other type of bayonet connections, for the output device or other types of connections for the electronic display may be used in alternate embodiments. While the present invention has been illustrated and described with reference to particular embodiments thereof, it will be apparent that modifications can be made and the invention can be practiced in other environments without departing from the spirit and scope of the invention, set forth in the accompanying claims.