Condition responsive indicating instrument

In a condition responsive indicating instrument for measuring pressure, temperature or the like, said instrument having an inlet means for communicating with a media whose conditions is to be measured, a Bourdon tube coupled to said inlet means and responsive to a predetermined distinct condition of said media for effecting a corresponding predetermined distinct displacement indicative thereof, mechanical linkage means coupled to said Bourdon tube and including a rotatable shaft, said linkage means being responsive to each predetermined distinct condition-indicative displacement for rotating said shaft through a corresponding predetermined distinct angle indicative thereof, cavity-defining means forming a cavity for enclosing said Bourdon tube and said linkage means, said cavity adapted to be filled with a protective liquid, a dial face having a predetermined range of condition-indicating indicia thereon and a pointer secured to said shaft for rotation therewith and disposed in front of said dial face so as to indicate a predetermined distinct condition-indicative indicia on said dial face which corresponds to said predetermined distinct angle of rotation of said shaft, an improved instrument housing comprising a unitary, integrally formed casing having a generally circular front support plate whose front surface is adapted to mount said dial face and whose rear face is adapted to form one end of said cavity-defining means and a cylindrical wall integral with said support plate and extending rearwardly therefrom to form the sides of said cavity-defining means, said improved housing further including back cover means normally engageble with the rearwardly facing portion of said cylindrical wall and forming the opposite end of said cavity-defining means to prevent the escape of the protective liquid from said cavity but responsive to the attainment of a predetermined unsafe pressure condition within said cavity for disengaging said cylindrical wall and relieving the excess pressure out of the back of said instrument without damage thereto, said back cover means including a generally circular, dish-shaped diaphragm adapted to seal said opposite end of said cavity;

• a generally circular, resiliently firm back cover plate overlaying said diaphragm such that the outer radial portion thereof is normally disposed in a first annular sealing position with respect to the rearward end of said cylindrical wall for urging said diaphragm to effect said seal but responsive to the attainment of said predetermined unsafe pressure condition within said cavity such that said outer radial portion is displaced away from said first sealing position to break the seal and relieve excess pressure;
• and means for mounting said diaphragm and said back cover plate in operable position with respect to said cylindrical wall.

In a condition responsive indicating instrument which includes a dial having a plurality of indicia thereon, pointer means adapted to indicate a distinct one of said indicia for each correspondingly distinct condition measured by the instrument, inlet means coupled to the media whose condition is being measured, a Bourdon element coupled to said inlet means and responsive to a given condition of said media for effecting a predetermined motion indicative thereof and a mechanical movement coupled between said Bourdon element and said pointer means for translating the condition-indicative motion of said Bourdon element into corresponding dial indications by said pointer means, an improved housing means including a casing having a support plate, said dial being secured to one side of support plate, mounting means secured to the opposite side of said support plate for mounting said mechanical movement so as to isolate same from external forces applied to said casing, said mounting means including a one-piece integral mounting plate having a base portion with first, second and third elongated members extending in a first direction therefrom, said first and third members defining a first plane and being rigidly secured flush against said opposite side of said support plate for securing said mounting plate to said casing, said base plate being rigidly secured to a portion of said inlet means for anchoring same, and said second elongated member being disposed between said first and third members and defining a second plate parallel to but spaced away from said first plane, said second member being adapted to be secured to said mechanical movement for suspending same away from said casing to isolate said mechanical movement from external forces applied to the casing.

In a condition responsive indicating instrument which includes a dial having a plurality of indicia thereon, pointer means adapted to indicate a distinct one of said indicia for each correspondingly distinct condition measured by the instrument, inlet means coupled to the media whose condition is being measured, a Bourdon element coupled to said inlet means and responsive to a given condition of said media for effecting a predetermined motion indicative thereof and a mechanical movement coupled between said Bourdon element and said pointer means for translating the condition-indicative motion of said Bourdon element into corresponding dial indications by said pointer means, an improved housing means including a casing having a support plate, said dial being secured to one side of support plate, mounting means secured to the opposite side of said support plate for mounting said mechanical movement so as to isolate same from external forces applied to said casing, said support plate being substantially circular in shape, said casing including said support plate is a one-piece, integrally-formed construction having a cylindrical wall portion extending rearwardly from said opposite side of said support plate to define an interior portion adapted to house said mounting means, said Bourdon element and said mechanical movement, said interior portion also being adapted to be filled with a protective fluid, said housing means further including sealing means operatively engaging the rear of said wall portion for preventing the escape of said protective fluid from said interior portion, the fluid being confined within said interior portion by said circular support plate, said cylindrical wall portion and said sealing means, said one-piece casing further including a second cylindrical wall integral with said support plate and extending forwardly therefrom to encircle said dial, said second wall having an externally threaded outer surface portion and an annular shoulder disposed on the inner surface thereof, said housing means further including a relatively durable substantially transparent window overlaying said dial, said window having a generally circular portion substantially parallel to and spaced apart from said support plate, said window including an annular lip disposed radially in from the periphery of said circular window portion and toward said support plate such that a radially outer annular bight is formed between the radially outer side of said annular lip and the dial-facing, radially peripheral surface of said circular window portion, said housing means further including a resilient O-ring seal and a window securing means having an annular ring portion dimensioned to at least partially overlay the non-dial facing, radially peripheral surface of said circular window portion for retainably engaging same and an internally threaded annular rim substantially normal to and integral with said ring portion for operatively engaging the exteranl threads of said second casing wall to move said ring portion and the window engaged thereby toward said support plate to compress said O-ring seal between the outer bight of said lip and said inner annular shoulder to provide a weatherproof seal therebetween.

In a condition responsive indicating instrument which includes a dial having a plurality of indicia thereon, pointer means adapted to indicate a distinct one of said indicia for each correspondingly distinct condition measured by the instrument, inlet means coupled to the media whose condition is being measured, a Bourdon element coupled to said inlet means and responsive to a given condition of said media for effecting a predetermined motion indicative thereof and a mechanical movement coupled between said Bourdon element and said pointer means for translating the condition-indicative motion of said Bourdon element into corresponding dial indications by said pointer means, an improved housing means including a casing having a support plate, said dial being secured to one side of support plate, mounting means secured to the opposite side of said support plate for mounting said mechanical movement so as to isolate same from external forces applied to said casing, said support plate being substantially circular in shape, wherein said casing including said support plate is a one-piece, integrally-formed construction having a cylindrical wall portion extending rearwardly from said opposite side of said support plate to define an interior portion adapted to house said mounting means, s aid Bourdon element and said mechanical movement, said interior portion also being adapted to be filled with a protective fluid, said housing means further including sealing means operatively engaging the rear of said wall portion for preventing the escape of said protective fluid from said interior portion, the fluid being confined within said interior portion by said circular support plate, said cylindrical wall portion and said sealing means, said sealing means including a "blow-out" back cover to act as a safety release to prevent the build up of excessive pressures within the instrument, said sealing means including a dual purpose flexible member for both sealing said back cover to normally prevent the escape of said fluid from said interior portion and for expanding and contracting to compensate for temperature variations, said rearwardly facing cylindrical wall including an annular shoulder on the inside thereof adjacent the distal end of said wall;

• said flexible member including a generally circular, dish-shaped diaphragm having a peripheral lip and its concave portion facing away from said support plate;
• said back cover including a relatively firm yet resilient material and is generally circular in shape, said cover includes a central portion, a radially outer peripheral portion whose annular inner surface is adapted to be urged against said distal end of said cylindrical wall, and an annular hump-shaped portion coupling the central portion to the outer portion, the peak of said hump-shaped portion facing said support plate and the radially outer side thereof curving to become integral with said outer portion;
• and said sealing means further including a substantially squared, generally S-shaped bracket having one end rigidly secured to said opposite side of said support plate and the opposite end centered over the back of said interior portion and adapted to be secured to the central portions of said diaphragm and said back cover so as to normally engage the peripheral lip of said dish-shaped diaphragm and the portion radially adjacent thereto with said annular hump-shaped portion and the curved radially outer side thereof to compress said peripheral lip and the portion radially adjacent thereto against said inside annular shoulder and the inside surfaces adjacent thereto to form a fluid-tight seal therebetween, said "blow-out" back cover being responsive to a predetermined unsafe amount of internal pressure exerted against said cover by said diaphragm for flexing to move said hump-shaped annular portion outwardly from said support plate thereby allowing said peripheral lip to break the seal with said inside annular shoulder to relieve the internal pressure.

In a condition responsive indicating instrument which includes a dial having a plurality of indicia thereon, pointer means adapted to indicate a distinct one of said indicia for each correspondingly distinct condition measured by the instrument, inlet means coupled to the media whose condition is being measured, a Bourdon element coupled to said inlet means and responsive to a given condition of said media for effecting a predetermined motion indicative thereof and a mechanical movement coupled between said Bourdon element and said pointer means for translating the condition-indicative motion of said Bourdon element into corresponding dial indications by said pointer means, an improved housing means including a casing having a support plate, said dial being secured to one side of support plate, mounting means secured to the opposite side of said support plate for mounting said mechanical movement so as to isolate same from external forces applied to said casing, said support being substantially circular in shape, wherein said casing including said support plate is a one-piece, integrally-formed construction having a cylindrical wall portion extending rearwardly from said opposite side of said support plate to define an interior portion adapted to house said mounting means, said Bourdon element and said mechanical movement, said interior portion also being adapted to be filled with a protective fluid, said housing means including sealing means operatively engaging the rear of said wall portion for preventing the escape of said protective fluid from said interior portion, the fluid being confined within said interior portion by said circular support plate, said cylindrical wall portion and said sealing means, said sealing means including a "blow-out" back cover to act as a safety release to prevent the build up of excessive pressures within the instrument, said sealing means including a dual purpose flexible member for both sealing said back cover to normally prevent the escape of said fluid from said interior portion and for expanding and contracting to compensate for temperature variations, said rearwardly facing cylindrical wall including an annular shoulder on the inside thereof adjacent the distal end of said wall;

• said flexible member including a generally circular, dish-shaped diaphragm having a peripheral lip and its concave portion facing away from said support plate;
• said back cover including a relatively firm yet resilient material and is generally circular in shape, said cover includes a central portion, a radially outer peripheral portion whose annular inner surface is adapted to be urged against said distal end of said cylindrical wall, and an annular hump-shaped portion coupling the central portion to the outer portion, the peak of said hump-shaped portion facing said support plate and the radially outer side thereof curving to become integral with said outer portion;
• and said sealing means further including a bracket having one end rigidly secured to the rear side of said inlet means and the opposite end centered over the back of said interior portion and adapted to be secured to the central portions of said diaphragm and said back cover so as to normally engage the peripheral lip of said dish-shaped portion and the curved radially outer side thereof to compress said peripheral lip and the portion radially adjacent thereto against said inside annular shoulder and the inside surfaces adjacent thereto to form a fluid-tight seal therebetween, said "blow-out" back cover being responsive to a predetermined unsafe amount of internal pressure exerted against said cover by said diaphragm for flexing to move said hump-shaped annular portion outwardly from said support plate thereby allowing said peripheral lip to break the seal with said inside annular shoulder to relieve the internal pressure.