Full drain and vent adapter for pressure sensing transmitter

A full drain and vent adapter for mounting a pressure sensing transmitter or similar test instrument to a standard manifold is reversible for use in either gas or liquid pressure sensing applications. Combination vent or drain plugs are provided at the top and bottom of the adapter to provide drains at the bottom of the adapter and vents at the top of the adapter, regardless of liquid or gas service applications.

BACKGROUND OF THE INVENTION
 1. Technical Field
 This invention relates generally to an adapter for mounting a
 pressure-sensing transmitter in a vertical orientation, and more
 particularly to such an adapter that is suitable for use in either gas or
 liquid pressure sensing applications.
 2. Background Art
 Multi-valve manifolds have been used to mount pressure sensing transmitters
 such as Rosemount.RTM. Coplanar.TM. style pressure transmitters. Such
 multi-valve manifolds are adapted for specific use in either a gas or in a
 liquid process application. Threaded plugs are typically installed in test
 ports on the top of the valve, and the valve is constructed in such a
 manner that prevents it from being reversed end for end, thus requiring
 separate configurations for liquid service and gas service applications.
 Additionally, it is difficult to drain condensate from the pressure
 cavities of the manifold and transmitter in order to avoid calibration
 errors. Also, since pressure sensing transmitters are now generally
 mounted directly to a multi-valve manifold in a field environment, it is
 difficult to accurately tighten the mounting bolts to assure that the high
 torque requirements specified by the transmitter manufacturer are met.
 The present invention is directed to overcoming the problems set forth
 above. It is desirable to have a simple adapter that can be directly
 mounted to a standard horizontal mount blocking manifold, which thereby
 places the transmitter sensing foils in a vertical plane. As the result of
 the transmitter sensing foils being disposed in a vertical plane,
 condensate or deposits on the foils will not affect measurement accuracy,
 and the foil face can be either fully vented or fully immersed in the
 pressure media. This is impossible with horizontally positioned foils. It
 is also desirable to have an adapter that is reversible end for end (top
 for bottom) so that the pressure transmitter can be used in either liquid
 or gas service applications. It is also desirable to have a full drain and
 vent adapter for pressure sensing transmitters that has a foil cavity
 design in the adapter that allows full drain or vent even if the adapter
 is misaligned vertically by up to 15%. Furthermore, it is desirable to
 have such a full drain and vent adapter for mounting pressure-sensing
 transmitters that allows factory or shop torquing of the transmitter head
 to the manufacturer's specified high torque values, and additionally
 protects the sensing foils during shipping, handling, and installation of
 the pre-assembled unit at a field site.
 SUMMARY OF THE INVENTION
 In one aspect of the present invention, a reversible adapter for
 selectively mounting a pressure-sensing transmitter to a manifold in
 either a liquid or a gas system has a first end surface in which a pair of
 vent ports are disposed, a second end surface that also has a pair of end
 ports disposed therein, first and second planar surfaces extending between
 the first and second end surfaces, and a pair of spaced-apart internal
 passageways. The first planar surface is adapted for mounting the adapter
 to a predefined manifold, and the second planar surface is adapted for
 mounting a pressure-sensing transmitter or test instrument thereon. The
 adapter also has a first set of apertures that extend through the adapter
 from the second planar surface to the first planar surface at a position
 approximate the first end surface, and a second set of apertures extending
 through the adapter from the second planar surface to the first planar
 surface at a position proximate the second end surface. The reversible
 adapter further includes a pair of spaced-apart internal passageways
 disposed in mutually parallel relationship. Each of the passageways
 respectively extend between a separate one of the pair of vent ports
 disposed in the first end surface and a corresponding separate one of the
 vent ports disposed in the second end surface.
 Other features of the reversible adapter embodying the present invention
 include the first planar surface having a pair of ports defined therein
 that are arranged to mate with a corresponding pair of ports on the
 predefined manifold, each port of the pair of ports being in respective
 communication with a separate one of the internal passageways in the body
 of the adapter. Other features include each member of the pair of ports on
 the first planar surface having a groove formed in the first planar
 surface that is disposed in spaced circumscribing relationship about the
 respective port. Still other features include the reversible adapter
 having a pair of ports defined on the second planar surface that are
 arranged to mate with a corresponding pair of ports on the pressure
 sensing transmitter, with each port of the pair of ports on the second
 planar surface being in respective communication with a separate one of
 the internal passageways in the body of the adapter.
 Yet additional features of the reversible adapter embodying the present
 invention include each aperture of the first set of apertures extending
 from the second planar surface to the first planar surface at a position
 proximate the first end surface has a smooth bore adapted to receive a
 fastening member therethrough for engagement with the base of the pressure
 sensing transmitter. Another feature includes each aperture of the second
 set of apertures extending from the second planar surface to the first
 planar surface at a position proximate the second end surface of the
 adapter has a threaded bore adapted to receive a fastening member extended
 through a portion of the predefined manifold.
 Yet another feature of the reversible adapter embodying the present
 invention includes the adapter body being reversibly mountable in a
 substantially vertical plane wherein the first end surface is positionable
 elevationally above the second end surface and the vent ports of the
 second end surface provide drain ports for the internal passageways of the
 body, and the second end surface is positionable elevationally above the
 first end surface and the vent ports of the first end surface provide
 drain ports for the internal passageways of the body when the adapter is
 mounted on the manifold of a gas processing system.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE PRESENT INVENTION
 The full drain and vent adapter for pressure-sensing transmitters,
 embodying the present invention, is generally defined in the drawings by
 the reference numeral 10. In FIG. 1, the adapter 10 is oriented for use in
 liquid surface applications, and in FIG. 2, the adapter 10 is oriented for
 use in gas surface applications.
 The full drain and vent adapter 10 has a body 12, defining a generally
 rectangular quadrilateral shape, having, as best shown in FIGS. 4 and 6, a
 first end surface 14 having a first pair of threaded vent ports 16 defined
 therein, and a second surface 18 having a second pair of threaded vent
 ports 20 defined therein. The adapter 10 also has a first planar surface
 22 extending between the first end 14 and second end 18 that is arranged
 for mounting the adapter 10 to a predefined manifold 24. The adapter 10
 further includes a second planar surface 26 that is spaced from the first
 planar surface 22 and extends between the first end surface 14 and the
 second end surface 18. The second planar surface 26 is arranged for
 mounting a pressure-sensing transmitter 28, or similar test instrument,
 thereon.
 A first set of apertures 30 extend from the second planar surface 26 to the
 first planar surface 22 at a position proximate the first end surface 14.
 In the illustrated embodiment, the first set of apertures 30 have a smooth
 bore adapted to receive a fastening member 32 therethrough for engagement
 with predefined threads provided in the base of the pressure sensing
 transmitter 28 whereby the transmitter 28 is removably secured to the
 adapter 12. The full drain and vent adapter 10 further includes a second
 set of apertures 34 extending from the second planar surface 26 to the
 first planar surface 22 at a position proximate the second end surface 18.
 In the illustrated embodiment, each aperture 34 of the second set of
 apertures has a threaded bore adapted to receive a fastening member 36
 extending through a flange portion of the manifold 24, whereby the adapter
 12 is removably attached to the manifold 24.
 Importantly, the full drain and vent adapter 10 embodying the present
 invention has two internal passageways 38, 40 which respectively extend
 between one of the first pair of vent ports 16 and a corresponding one of
 the second pair of vent ports 20. Each port of the first and second pair
 of vent ports 16, 20 is internally threaded to receive threaded plugs 42,
 which desirably have needle valves 44 disposed therein, so that the
 passageways 38, 40 can be opened, either incrementally or fully, to the
 atmosphere. In whichever orientation the adapter 10 is used, the needle
 valve plugs 42, 44 positioned at the top of the adapter 10 serve to vent
 the passageways 38, 40 to atmosphere, and the needle valve plugs 42, 44
 disposed at the bottom of the adapter 10 provide drains for the respective
 passageways 38, 40.
 A pair of inlet ports 46 are disposed in the first planar surface 22 and
 are arranged to mate with predefined discharge ports provided on the
 manifold 10, such as the illustrated standard horizontal mount manifold
 illustrated in FIGS. 1 and 2. A pair of discharge ports 48 are disposed in
 the second planar surface 26 and are arranged to mate with predefined
 inlet ports of the pressure-sensitive transmitter 28, or a similar test
 instrument. Both inlet ports 46 and both discharge ports 48 are
 appropriately sealed at their interface with the adjacent manifold or
 transmitter, and are in direct fluid communication with a respective one
 of the internal passageways 38, 40. Desirably, each of the inlet ports 46
 has an annular groove 50 formed in the first planar surface 22, in spaced
 circumscribing relationship about the respective port 46, for receiving an
 appropriate seal member, not shown. The discharge ports 48 may be
 similarly sealed with a seal member positioned in a corresponding groove
 on either the second planar surface 26 on the bottom of the transmitter
 28.
 The inlet ports 46 communicate respectively with one of the internal
 passageways 38, 40 by way of a short inclined passageway 52 extending
 between the respective inlet port 46 and a corresponding one of the
 internal passageways 38, 40. The passageways 52 are sloped, as best seen
 in FIG. 3, to provide drainage of cavities within the attached manifold 24
 and transmitter 28 through the passageways 38, 40 to the drains 16 in
 liquid service applications. The discharge ports 48 diverge radially
 outwardly from the second planar surface 26 at the transmitter side of the
 adapter 10, as indicated by reference number 54, and then converge
 inwardly to the bottom of the port 48. The divergent sections 54 of the
 discharge port 48 prevent entrapment of liquid when the adapter 10 is
 mounted in a vertically misaligned position.
 When the full drain and vent adapter 10 for pressure-sensing transmitters
 is used in liquid service applications, the adapter 10 is oriented as
 shown in FIG. 1, 4 and 6. That is, the threaded second holes 34 are
 provided in the upper portion of the adapter 10 to receive the threaded
 bolts 36 extending through the mounting flange of the standard horizontal
 mount manifold 24. Straight through-holes 30 are provided in the lower
 portion of the adapter 10 to permit for passage of mounting screws 32
 therethrough for engagement with threaded holes provided in the base of
 the pressure sensing transmitter 28. The screws 32 are typically torqued
 to high values as specified by the manufacture of the transmitter 28.
 When the full drain and vent adapter 10 for pressure-sensing transmitters
 is used in gas service applications, as shown in FIG. 2, the adapter 10 is
 turned 180.degree., i.e., top for bottom, from the orientation shown on in
 FIG. 1. In gas service applications, the drain plugs 42, 44 used in liquid
 service applications become vent plugs 42, 44, and the vent plugs 42, 44
 in the liquid service applications become drain plugs 42, 44. In either
 application, the sensor foil area of the transmitter 28 lies at or very
 close to the second planar surface 26 and the ports 48 when the
 transmitter 28 and adapter 10 are joined together.
 Thus, it can be readily seen that the full drain and vent adapter 10, for
 pressure-sensing transmitters, embodying the present invention allows the
 transmitter sensing foils to be positioned in a vertical plane while using
 a standard horizontal mount manifold 24. Advantageously, the vertical
 orientation of the sensing foils prevents condensate or deposits on the
 foils from affecting measurement accuracy. Also, as a result of the full
 drain and vent characteristics of the adapter 10, the foil face can be
 fully vented or fully immersed in a pressurized media, rendering the
 transmitter suitable for use in either liquid or gas service applications.
 Another important advantage of the full drain and vent adapter 10 is that
 the adapter cavities 48 adjacent the sensing foils of the transmitter 28
 are constructed so that they allow full drain or vent even if the adapter
 10 is not precisely vertically aligned. A further advantage is that the
 full drain and vent adapter 10 embodying the present invention allows
 factory or shop assembly of the adapter 10 to a transmitter base, whereby
 the screws 32 securing the adapter 10 to the transmitter head can be
 tightened to the manufacturer's specified torque value in a factory or
 controlled shop environment. The thus-assembled adapter 10 and transmitter
 28 provides desirable protection for the sensing foils of the transmitter
 28 during subsequent shipment, handling, and installation.
 Although the present invention is described in a specific exemplary
 embodiment, with specific illustrative port and passageway arrangements
 and drain/vent port constructions, those skilled in the art will recognize
 that changes in those arrangements and constructions can be made without
 departing from the spirit of the invention. Such changes are intended to
 fall within the scope of the following claims. Other aspects, features and
 advantages of the present invention may be obtained from a study of this
 disclosure and the drawings, along with the appended claims.