JP2006514265A - Pressure sensor housing and assembly - Google Patents

Abstract

A pressure sensor housing and assembly are disclosed. The pressure sensor may have a manifold and header with one integral housing. The integral housing has a pressure inlet in communication with the elongated tube. The integral housing may also have a sensing die coupled with the elongated tube for receiving a pressure input signal through the pressure inlet. The sensing die may sense the applied pressure and derive an electrical signal from the applied pressure.

Description

  The present invention relates generally to sensors, and more particularly to pressure sensor housings and assemblies.

  Pressure measurements are typically made in the process control industry (eg, paper, oil refining, chemical manufacturing, etc.), vehicles (eg, engine hydraulics), aircraft manufacturing, utilities and heating, and other industries. Pressure measurements are usually made as absolute measurements, gauge measurements, or differential measurements. An absolute pressure sensor measures pressure against a vacuum, a gauge sensor measurement measures pressure against atmospheric pressure, and a differential sensor measurement measures a pressure difference between two input values.

  The pressure sensor may incorporate an “up-the-tube” pressure inlet design to possibly deal with differential, gauge and absolute pressure measurements. The tube upstream pressure sensor can measure pressure without damaging the sensor components. For example, tube upstream pressure measurements prevent fluid from contacting the sensing die electronics. A typical tube upstream pressure sensor has a glass header connected to the manifold (via a laser weld). Also, the printed circuit board is connected upright to the glass header using a flexible printed circuit board joint (ie, flex tape). Manufacturing the pressure sensor in this way reduces the amount of space on the circuit board due to laser welding of the header and flex tape connection of the header, since both the laser weld and the flex tape connection are used on the circuit board. Reduce.

  Existing tube upstream pressure sensors are also configured so that the pressure input and electrical output flow in opposite directions, causing interference between the sensor input and output.

  As a result, existing tube upstream pressure sensors cannot meet manufacturing and performance requirements, and therefore pressure sensors that are manufactured without such existing difficulties and problems are desired.

  According to an exemplary embodiment, an integral housing is provided that includes a pressure inlet defined through a surface of the integral housing. The housing also has an elongate tube disposed within the integral housing. The elongate tube has a first end and a second end. The first end is in pressure communication with the pressure inlet. The housing also has a sensing die attached to the second end of the elongated tube so that the pressure present at the pressure inlet can be measured by the sensing die.

  In another embodiment, a pressure sensor assembly having a first end and a second end is provided. The first end has a surface with a pressure inlet comprising an elongated tube. The assembly also has a sensing die with a pressure sensitive surface. The sensing die is coupled to an elongated tube and mounted such that a pressure sensing surface is substantially perpendicular to the surface of the housing with the pressure inlet. The assembly also includes a circuit board coupled to the second end of the integral housing so as to be substantially perpendicular to the surface of the housing with the pressure inlet.

  In yet another embodiment, a tube upstream sensor is provided having an integral housing with a pressure inlet defined through the surface of the integral housing. The housing also has a sensing die disposed within the integral housing. The sensing die is in pressure communication with the pressure inlet. The housing further includes an elongated Pyrex tube disposed within the integral housing. The elongated Pyrex tube is in pressure communication with the pressure inlet.

These as well as other features and advantages of the present invention will become apparent to those of ordinary skill in the art by reading the following detailed description, with appropriate reference to the accompanying drawings.
Referring to the accompanying drawings, elements having the same reference numeral represent like elements throughout.

  In the exemplary embodiment, a tube upstream pressure sensor assembly is shown. The assembly may have an integral housing with a manifold and header connected to the circuit board. The integral housing may be free of a flex tape joint or a laser weld joint, like an existing tube upstream pressure sensor, to increase circuit board space compared to an existing pressure sensor assembly. The tube upstream sensor also insulates the electronic side of the sensing die from the process fluid input signal. Thus, the process fluid input signal does not interfere with the electrical output signal using such a configuration.

  Referring to FIG. 1, one embodiment of a pressure sensor assembly 100 is shown. The pressure sensor assembly 100 includes a printed circuit board 102, a manifold 104, and a header 106. Manifold 104 and header 106 may include a single integrated pressure sensor housing 108. In another embodiment, the manifold 104 and the header 106 may be separate pieces that are attached or welded together to form an integral housing 108. The printed circuit board 102 may be mounted to the integrated housing 108 using screws 110 (ab) or equivalent. The integral housing 108 has a base 112 whose surface 114 has an opening that allows a pressure signal to be measured (the opening is not shown in FIG. 1 for ease of illustration). The integral housing 108 also has leads (not shown in FIG. 1) that pass through the printed circuit board 102. Solder contacts 116 conductively couple the leads to the printed circuit board 102. The printed circuit board 102 may be mounted to the integrated housing 108 such that it is perpendicular to the surface 114 of the base 112 (ie, in an upright position relative to the integrated housing 108).

  The base 112 of the integral housing 108 may be a generally planar mounting surface that allows the integral housing 108 to be mounted with any generally planar surface. The integral housing 108 may comprise a stainless steel material, but other materials are possible.

  The pressure sensor assembly 100 includes a header 106 that is disposed substantially perpendicular to the manifold 104. By integrating the header 106 and manifold 104 into one integral housing 108 and rotating the header 106 about 90 ° from the manifold 104, several advantages of the assembly and components can be realized. For example, integrating header 106 and manifold 104 eliminates mounting header 106 and manifold 104 to each other, which eliminates manufacturing steps and additional components such as laser weld joints. Also, rotating the header 106 to be approximately perpendicular to the manifold 104 allows the printed circuit board 102 to be soldered directly to the header 106, which can be a separate flex tape connection or complementary. Eliminates additional manufacturing and processing steps such as complex connectors. Also, the increased area of the printed circuit board 102 can be used due to the shape of the pressure sensor assembly 100.

  Referring to FIG. 2, a cover 200 for the pressure sensor assembly 100 of FIG. 1 is shown. The cover 200 is made of steel, metal, ceramic, etc., and can protect the pressure sensor assembly 100 from harsh environments. Cover 200 may slide over printed circuit board 102 and integral housing 108 to close and protect them. The cover 200 may be attached to the pressure sensor assembly 100 at the base 112 of the integral housing 108 by a friction fit, snap fit, screw or other means. Closing the pressure sensor assembly 100 using the cover 200 provides a sealed package for the pressure sensor assembly 100. The sealed package may reduce the effect of moisture or moisture on the printed circuit board 102 or other electronic components of the pressure sensor assembly 100.

  FIG. 3A shows a front isometric view of the integrated housing 108. FIG. 3B shows a rear isometric view of the integrated housing 108. As shown in FIG. 3B, the header 106 includes pins 300 for attachment to the printed circuit board 102. The pins 300 are disposed in corresponding openings in the printed circuit board 102 and may be soldered to the printed circuit board 102. The pin 300 may be a small electric wire. Although only seven pins 300 are shown in FIG. 3B for ease of illustration, any desired number of pins may be used. Also, the pins 300 may be configured or arranged at different positions on the header 106 depending on the desired mounting of the printed circuit board 102.

  FIG. 3C is a cross-sectional view of the integrated housing 108. The integral housing 108 may include a sensing die 302, an elongated tube 304, a pressure inlet 306 in the base 112, and a plurality of connecting leads 308. The elongate tube 304 is disposed within the cavity 310 of the integral housing 108. The elongate tube 304 may be a cylindrical tube with openings at both ends, but other shapes are possible. The elongate tube 304 may be mounted obliquely relative to the integral housing 108 that includes the pressure intake 306. For example, as shown in FIG. 3C, the cylindrical portion of the elongated tube 304 is disposed parallel to the base 112 of the unitary housing 108. However, the elongate tube 304 may be mounted in other arrangements as well. The elongated tube 304 may be glued with epoxy resin in the cavity 310 or soldered in place.

  One end 312 of the elongated tube 304 is in communication with the pressure inlet 306. A sensing die 302 is connected to the other end 314 of the elongated tube 304. Sensing die 302 senses pressure at surface 316 and creates an electrical signal proportional to the pressure. Input pressure applied to the sensing die 302 is transmitted through the pressure inlet 306 and through the elongated tube 304 where it reaches the surface 316 of the sensing die 302. The input pressure may be applied by liquid or gas.

  The sensing die 302 may comprise a flexible diaphragm that functions as a resistive element, with strain gauges joined to the diaphragm or distributed within the diaphragm. Under pressure induced strain, the resistance value of the strain gauge changes and this change in resistance value can be converted to an electrical output proportional to the input pressure using an appropriate circuit. The sensing die 302 may also comprise a capacitive sensor whose pressure diaphragm is one plate of a capacitor whose value changes due to a pressure induced shift. Sensing die 302 may also be a piezoresistive pressure sensor or a silicon cell. A piezoresistive pressure sensor has a diaphragm with a piezoresistive strain gauge dispersed on a sensing die. By measuring the voltage on a piezoresistive strain gauge, the pressure applied to the diaphragm is determined. Other variations of the sensing die are possible as well.

  The sensing die 302 measures the pressure difference between the two sides of the diaphragm as a whole. The sensing die 302 can measure absolute pressure, differential pressure or gauge pressure as required.

  The elongate tube 304 may be made of Pyrex or other material having a thermal expansion coefficient that is approximately the same as the thermal expansion coefficient of the sensing die 302. This reduces and / or prevents temperature-induced variations in signal output caused by using materials for sensing die 302 and elongated tube 304 having different coefficients of thermal expansion. For example, the sensing die 302 may be rigidly attached to the elongate tube 304, and temperature induced errors in pressure measurements may occur due to thermal expansion coefficient imbalances.

  A connecting lead 308 extends from the sensing die 302 to the pin 300. Connection lead 308 is wire bonded to sensing die 302 or connected through other means or soldered to pin 300.

  4 is a cross-sectional view of the pressure sensor assembly 100 of FIG. 1 with the cover 200 attached. The surface 114 of the integral housing 108 and the cover 200 form a seal 400. As shown, the surface 316 of the sensing die 302 is substantially parallel to the printed circuit board 102 and is substantially perpendicular to the surface 114 of the integrated housing 108. Also, the surface 114 is substantially perpendicular to the surface 402 of the printed circuit board 102. Although the vertical or parallel relationship between the elements described herein is not important for all embodiments of the invention, other configurations may achieve the advantages of the invention.

  FIG. 4 also shows the output port 404 of the printed circuit board 102. The output port 404 is conductively coupled to the end 406 of the printed circuit board 102 opposite the integral housing 108. However, the output port 404 may be anywhere on the pressure sensor assembly 100.

  The pressure sensor assembly 100 shown in FIGS. 1-4 and other configurations described herein are set forth for purposes of example only, and other configurations and elements may be used instead, It should be understood that these elements may be omitted entirely. For example, the selection of materials for use in the pressure sensor assembly 100 is selected to withstand high pressures, high temperatures or other environmental conditions.

  The pressure sensor assembly 100 shown in FIGS. 1-4 can be employed as a tube upstream pressure sensor assembly. However, those skilled in the art will appreciate that the pressure sensor assembly 100 may be used in accordance with other pressure sensor technologies.

  Those skilled in the art to which the present invention pertains may make modifications resulting in other embodiments employing the principles of the present invention without departing from the spirit and features of the invention. Accordingly, the embodiments described herein are illustrative in all respects and are not intended to be limiting, and the scope of the invention is thus not limited by the following description, but by the appended claims. Indicated by a range of. Thus, the present invention has been described with respect to particular embodiments and modifications obvious to those skilled in the art are within the scope of the present invention. Other embodiments are possible as well.

FIG. 6 is a rear view of one embodiment of a pressure sensor assembly. FIG. 2 shows a cover for the pressure sensor assembly of FIG. 1. FIG. 2 is a front isometric view of a portion of the pressure sensor assembly of FIG. 1. FIG. 2 is a rear isometric view of a portion of the pressure sensor assembly of FIG. 1. FIG. 2 is a cross-sectional view of a portion of the pressure sensor assembly of FIG. FIG. 3 is a cross-sectional view of the pressure sensor assembly of FIG. 1 and a portion of the cover of FIG.

Claims (20)

An integral housing;
A pressure inlet defined through a surface of the integral housing;
An elongate tube disposed within the integral housing, having a first end and a second end, the first end being in pressure communication with the pressure inlet;
A pressure sensor comprising a sensing die attached to the second end of the elongated tube, wherein the pressure present at the pressure inlet is measurable by the sensing die.   The pressure sensor of claim 1, wherein the integral housing comprises a manifold and a header.   The pressure sensor of claim 1, wherein the elongated tube comprises a material having approximately the same coefficient of thermal expansion as the sensing die.   The sensing die has a pressure sensitive surface, the sensing die of the elongated tube such that the pressure sensitive surface is perpendicular to the surface through which the pressure inlet is defined. The pressure sensor according to claim 1, which is attached to the second end.   The pressure sensor of claim 1, further comprising a cover hermetically attached to the integral housing.   The pressure sensor of claim 1, wherein the elongated tube has a low coefficient of thermal expansion.   The pressure sensor according to claim 1, wherein the elongated tube is disposed obliquely in the integrated housing.   The pressure sensor according to claim 1, wherein the elongated tube has a cylindrical shape.   The pressure sensor according to claim 1, wherein the elongated tube is a Pyrex tube.   The pressure sensor of claim 1, wherein the surface of the integral housing through which the pressure inlet is defined is a substantially flat mounting surface.   The pressure sensor of claim 10, wherein the elongated tube is disposed substantially parallel to the flat mounting surface. An integral housing having a first end and a second end, the first end having a surface with a pressure inlet, the pressure inlet having an elongated tube;
A sensing die having a pressure sensing surface coupled to an elongated tube and mounted such that a pressure sensing surface is substantially perpendicular to a surface of the housing comprising the pressure inlet, and a circuit board comprises the pressure inlet. And a circuit board coupled to the second end of the unitary housing to be substantially perpendicular to the surface of the housing.   The pressure sensor assembly of claim 12, wherein the sensing die has approximately the same coefficient of thermal expansion as the elongated tube.   The pressure sensor assembly of claim 12, wherein the sensing die senses pressure through the pressure inlet.   The pressure sensor assembly of claim 12, wherein the elongated tube is a Pyrex tube.   The pressure sensor assembly of claim 12, further comprising a plurality of leads that electrically couple the circuit board with the sensing die.   The pressure sensor assembly of claim 12, further comprising a cover hermetically attached to the integral housing. A pressure inlet defined through the surface of the integral housing;
A sensing die disposed within the integral housing and in pressure communication with the pressure inlet;
A tube upstream pressure sensor comprising an integral housing having an elongated Pyrex tube disposed in the integral housing and in pressure communication with the pressure inlet.   The tube upstream pressure sensor of claim 18, wherein the sensing die comprises a material having substantially the same coefficient of thermal expansion as the elongated pyrex tube.   The tube upstream pressure sensor of claim 18, wherein the integral housing comprises a header and a manifold.

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