Patent Description:
Differential pressure measurements can be accomplished by a differential pressure transducer which provides an output that is the difference between two pressures. In the case of the absolute pressure transducer, the output is truly indicative of monitored pressure, e.g. relative to a vacuum. A duplex differential pressure transducer traditionally has two separate absolute pressure capsules to measure differential pressure across a medium such as, for example, an oil filter. The monitored absolute pressure outputs from each pressure capsule are compared to determine the pressure difference between an inlet side and an outlet side of the oil filter.

Generally, traditional duplex pressure transducers must meet certain accuracy and size requirements. Larger pressure capsules increase pressure measurement accuracy. But, on the other hand, duplex pressure transducers are generally found in confined areas where space and clearance are critical, making dimension requirements and size high priority considerations. Duplex pressure transducers generally house the pressure capsules in a side-by-side horizontal arrangement.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for duplex pressure transducers that allow for improved accuracy while still conforming to envelope size restrictions. There also remains a need in the art for such duplex pressure transducers that are easy to make and use. The present disclosure provides a solution for these problems.

<CIT> discloses a differential pressure instrument having a sealed interior pressure chamber containing a fill-liquid, and a pair of flexible diaphragms to apply to the fill-liquid an input differential pressure to be sensed by a chip within the chamber.

<CIT> discloses sensor circuitry for a sensor having fluid-filled portions in communication with each other.

<CIT> discloses a transducer which generates a force signal in an external member directly proportional to differential pressure.

The invention is a transducer baseplate according to claim <NUM>.

A transducer baseplate includes a base with a protrusion extending from the base along a longitudinal axis of the transducer baseplate and a pair of respective pressure plena. Each plenum is in fluid connection with an area external to the protrusion through a respective pressure line. The transducer baseplate is characterised in that it further comprises a pair of opposed transducer receptacles defined within the protrusion. The pressure plena are separated by a plenum wall, one plenum in fluid communication with each receptacle, respectively. The pressure lines provide a direct fluid path to their respective receptacles.

The receptacles each have a cross-sectional shape and the base has a cross-sectional perimeter in a plane perpendicular to the longitudinal axis. The combined cross-sectional shapes of the receptacles may be too large to fit non-overlappingly within the cross-sectional perimeter of the base. The pressure lines can also each have a cross-sectional shape. The combined cross-sectional shapes of one pressure line and of one receptacle may be too large to fit within the cross-sectional perimeter of the base.

In accordance with certain embodiments, the receptacles can have circular cross-sections and each can have a receptacle diameter in a plane aligned with the longitudinal axis.

The base and pressure lines can also have circular cross-sections. The base can have a base diameter in a plane perpendicular to the longitudinal axis where the combined receptacle diameters are greater than the base diameter.

It is contemplated that the receptacles can be configured to each receive a separate high temperature pressure capsule. In addition, the protrusion can also include an end surface configured to secure circuitry. The transducer baseplate can also include a mounting flange below the base with respect to the longitudinal axis. The pressure lines can define a channel through the mounting flange, through the base, and through the protrusion to provide a direct fluid path to their respective receptacles. The mounting flange can have sealing sockets defined proximate to respective first ends of the pressure lines. The sealing sockets can be configured to receive seals. Further, the transducer baseplate is configured to withstand temperatures from -<NUM> to <NUM> degrees Celsius (<NUM> to <NUM> degrees Kelvin), and pressures from <NUM> to <NUM> psi (<NUM> kPa to <NUM> MPa) while still maintaining less than ± <NUM>% error.

A duplex pressure transducer includes a transducer baseplate as described above, a separate high temperature pressure capsule secured in each receptacle, circuitry, and a transducer housing. The circuitry is operatively connected to an end surface of the protrusion each in electronic communication with a separate high temperature pressure capsules. The transducer housing is sealed over at least the transducer receptacles, high temperature pressure capsules, and circuitry. The circuitry can include a pair of opposing circuit boards. The circuit boards each can be configured to receive pressure readings from their respective separate high temperature pressure capsules.

In accordance with certain embodiments, the high temperature pressure capsules can be spaced away from the transducer housing such that there is clearance for at least one electrical cable each between the high temperature pressure capsules and the transducer housing. The transducer housing can be affixed to the baseplate by weld joints located on the base, and can include a port configured to receive electrical connectors. The transducer housing and weld joints can be configured to withstand burst pressures of up to <NUM> psi (<NUM> MPa).

It is contemplated that the transducer baseplate, high temperature pressure capsules, circuitry and transducer housing can be configured to withstand temperatures from -<NUM> to <NUM> degrees Celsius (<NUM> to <NUM> degrees Kelvin) and pressures from <NUM> to <NUM> psi (<NUM> kPa to <NUM> MPa) while still maintaining less than ± <NUM>% error.

So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below by way of example only and with reference to certain figures, wherein:.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a perspective view of an exemplary embodiment of a transducer baseplate constructed in accordance with the present disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of a transducer baseplate constructed in accordance with the present disclosure, or aspects thereof, are provided in <FIG>, as will be described.

In reference to <FIG>, a transducer baseplate <NUM> includes a base <NUM>, a protrusion <NUM> extending from base <NUM> along a longitudinal axis A, a pair of opposed transducer receptacles <NUM> defined within protrusion <NUM>, and pressure plena <NUM> associated with each receptacle <NUM>. Protrusion <NUM> has an end surface <NUM>. Transducer baseplate <NUM> also includes a mounting flange <NUM>. Mounting flange <NUM> is below base <NUM> with respect to longitudinal axis A, as oriented in <FIG>. Mounting flange <NUM> has sealing sockets <NUM> defined proximate to respective first ends <NUM> of pressure lines <NUM>. Sealing sockets <NUM> are configured to receive seals (not shown). A variety of seals can be used, such as, o-ring seals.

Pressure plena <NUM> are separated by a plenum wall <NUM>, each plenum <NUM> being in fluid connection with an area external to protrusion <NUM> through a respective pressure line <NUM>. Pressure lines <NUM> provide a direct fluid path to their respective receptacles <NUM>. Transducer baseplate <NUM> is configured to withstand temperatures from -<NUM> to <NUM> degrees Celsius (<NUM> to <NUM> degrees Kelvin), and pressures from <NUM> to <NUM> psi (<NUM> kPa to <NUM> MPa) while still maintaining less than ± <NUM>% error. It can be appreciated that the temperature and pressure ranges listed above are working temperatures and pressures for maintaining less than ± <NUM>% error and that baseplate <NUM> can be configured to withstand higher temperatures and pressures.

Now with reference to <FIG>, each receptacle <NUM> is configured to receive a separate high temperature pressure capsule <NUM>. Pressure lines <NUM> each define a channel through mounting flange <NUM>, through base <NUM>, and through protrusion <NUM> to provide a direct fluid path to their respective receptacles <NUM>. Receptacles <NUM> each have a cross-sectional shape B, and base <NUM> has a cross-sectional perimeter C, in a plane perpendicular to the longitudinal axis A. Combined cross-sectional shapes B are too large to fit non-overlappingly within cross-sectional perimeter C of base <NUM>. In another aspect, each receptacle <NUM> has a receptacle diameter E in a plane parallel to longitudinal axis A. Base <NUM> has a base diameter F in a plane perpendicular to the longitudinal axis A. The combined receptacle diameters E are greater than base diameter F.

It can be appreciated that, high temperature pressure capsules <NUM> do not fit inside the transducer housing (<NUM>) in a side by side arrangement, i.e. where each receptacle diameter E is aligned perpendicular to longitudinal axis A. Instead, a vertical configuration of high temperature pressure capsules <NUM>, i.e. with each receptacle diameter E aligned parallel to longitudinal axis A, is used to create a transducer that accommodates larger capsules than traditional configurations, therein making the transducer more accurate. Further, it can be appreciated that while shown substantially in cylindrical shapes, high temperature pressure capsules <NUM> and receptacles <NUM>, can be of any suitable shape.

Now with reference to <FIG>, another exemplary embodiment is shown, namely a duplex pressure transducer <NUM>. Duplex pressure transducer <NUM> includes a transducer baseplate <NUM> as described above, a separate high temperature pressure capsule <NUM> secured in each receptacle <NUM>, circuitry <NUM>, and a transducer housing <NUM>. Circuitry <NUM>, shown as a pair of opposing circuit boards, are operatively connected to end surface <NUM> of protrusion <NUM> each in electronic communication with separate high temperature pressure capsules <NUM>. Each circuit board <NUM> is configured to receive pressure readings from its respective separate high temperature pressure capsule <NUM>. The high temperature pressure capsules <NUM> are spaced away from transducer housing <NUM> such that there is clearance for at least one electrical cable each, shown schematically, between high temperature pressure capsules <NUM> and transducer housing <NUM>.

Now with reference to <FIG>, transducer housing <NUM> is hermetically sealed over at least transducer receptacles <NUM>, high temperature pressure capsules <NUM>, and circuit boards <NUM>. Transducer housing <NUM> is affixed to the baseplate <NUM> by weld joints <NUM> located on base <NUM>. Further, transducer housing <NUM> includes a port <NUM> configured to receive electrical connectors <NUM>, shown schematically. It can be appreciated that while one port <NUM> is shown, any suitable number of ports can be defined in the transducer housing <NUM> for a given application. The thickness and material of transducer housing <NUM> and weld joints <NUM> is configured to withstand burst pressures of up to <NUM> psi (<NUM> MPa).

Those having skill in the art will readily appreciate that duplex pressure transducer <NUM> uses separate high temperature pressure capsules <NUM> to measure differential pressure across a medium, such as an oil filter. Duplex pressure transducer <NUM> is designed to have less than ± <NUM>% error over the operating ranges of -<NUM> to <NUM> degrees Celsius (<NUM> to <NUM> degrees Kelvin) and <NUM> to <NUM> psi (<NUM> kPa to <NUM> MPa). To achieve such accuracy under these high pressure and temperature conditions, one having skill in the art will readily appreciate that the size of the high temperature pressure capsules <NUM> may need to increase. As such, duplex pressure transducer <NUM> is configured to allow for a larger capsule, without sacrificing size or pressure and temperature capacity. The vertical transducer baseplate <NUM> configuration for the high temperature pressure capsules <NUM>, as described above, allows for increased accuracy by tolerating a larger capsule, without sacrificing duplex pressure transducer size, or pressure and temperature capacity.

Claim 1:
A transducer baseplate (<NUM>) comprising:
a base (<NUM>) with a protrusion (<NUM>) extending from the base along a longitudinal axis (A) of the transducer baseplate, wherein the base has a cross-sectional perimeter (C) in a plane perpendicular to the longitudinal axis; and
a pair of pressure plena (<NUM>), each plenum being in fluid connection with an area external to the protrusion through a respective pressure line (<NUM>);
characterised in that the transducer baseplate further comprises a pair of transducer receptacles (<NUM>) defined within the protrusion and opposed across the longitudinal axis (A), wherein the receptacles each have a cross-sectional shape (B) in a plane parallel to the longitudinal axis;
wherein the pressure plena are separated by a plenum wall (<NUM>), one plenum in fluid communication with each receptacle, respectively; and
wherein the pressure lines provide a direct fluid path to their respective receptacles.