Fluid pressure measuring device

Claim 2

A fluid pressure measuring device comprising: a metal piece having a body portion having a center passageway of cylindrical shape extending from one end thereof to a point short of the opposite end thereof, such body portion having two flat parallel sides lying parallel to the center axis of the passageway; a first strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane transverse to the center axis of the passageway; a second strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane parallel to the center axis of the passageway; and circuit means for enabling the strain gages to be connected in circuit with one another whereby the first strain gage may provided an indication of fluid pressure within the passageway and the second strain gage may provide temperature compensation for the device.

Claim 3

A fluid pressure measuring device comprising: a metal piece having a body portion having a center passageway extending from one end thereof to a point short of the opposite end thereof, such body portion having two flat parallel sides lying parallel to the center axis of the passageway and two curved sides interconnecting the two flat sides, such curved sides having a common axis of revolution which coincides with the center axis of the passageway; a first strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane transverse to the center axis of the passageway; and circuit means for enabling the strain gages to be connected in circuit with one another whereby the first strain gage may provide an indication of fluid pressure within the passageway and the second strain gage may provide temperature compensation for the device.

Claim 4

A fluid pressure measuring device comprising: a metal piece having a body portion having a center passageway extending from one end thereof to a point short of the opposite end thereof, such body portion having two flat parallel sides lying parallel to the center axis of the passageway and two curved sides interconnecting the two flat sides, such curved sides having a common axis of revolution which coincides with the center axis of the passageway; a first strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane transverse to the center axis of the passageway; and circuit means for enabling the strain gages to be connected in circuit with one another whereby the first strain gage may provide an indication of fluid pressure within the passageway and the second strain gage may provide temperature compensation for the device.

Claim 5

A fluid pressure measuring device comprising: a metal piece having a body portion having a center passageway extending from one end thereof to a point short of the opposite end thereof, such body portion having two flat parallel sides lying parallel to the center axis of the passageway; a first strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane transverse to the center axis of the passageway; a second strain gage bonded to one of the flat sides above the passageway and centered at a point where direct axial deformation of the body portion caused by fluid pressure within the passageway is offset by the opposing axial deformation resulting from the transverse deformation caused by fluid pressure within the passageway for measuring the strain in a plane parallel to the center axis of the passageway; and circuit means for enabling the strain gages to be connected in circuit with one another whereby the first strain gage may provide an indication of fluid pressures within the passageway and the second strain gage may provide temperature compensation for the device.

Claim 6

A fluid pressure measuring device comprising: a metal piece having a body portion having a center passageway extending from one end thereof to a point short of the opposite end thereof, such body portion having two flat parallel sides lying parallel to the center axis of the passageway; a first strain gage bonded to one of the flat sides above the passageway for measuring the strain in a plane transverse to the center axis of the passageway; a second strain gage bonded to one of the flat sides above the passageway and centered at a point where direct axial deformation of the body portion caused by fluid pressure within the passageway is offset by the opposing axial deformation resulting from the transverse deformation caused by fluid pressure within the passageway for measuring the strain in a plane parallel to the center axis of the passageway; and circuit means for enabling the strain gages to be connected in circuit with one another whereby the first strain gage may provide an indication of fluid pressures within the passageway and the second strain gage may provide temperature compensation for the device.

Claim 7

A fluid pressure measuring device comprising: a relatively rigid metal piece having an enlarged head portion at one end thereof, a reduced body portion extending from the head portion, and a center passageway extending through the head portion and into the body portion to a point short of the free end of the body portion, the portion of such passageway within the body portion being of cylindrical shape, such body portion having two flat parallel sides lying parallel to the center axis of the passageway and two curved sides interconnecting the two flat sides, such curved sides having a common axis of revolution which coincides with the center axis of the passageway, the width of the body portion transverse to the passageway and parallel to the flat sides being equal to approximately twice the thickness of the body portion between the flat sides and the passageway length within the body portion being equal to approximately twice the thickness of the body portion between the flat sides; a first pair of semiconductor strain gages individually bonded to different ones of the two flat sides above the passageway, each being centered at approximately the midpoint along the passageway length within the body portion and oriented for measuring the strain in a plane transverse to the center axis of the passageway; a second pair of semiconductor strain gages individually bonded to different ones of the two flat sides above the passageway and located nearer the closed end of the passageway than the first pair of strain gages and oriented for measuring the strain in a plane parallel to the center axis of the passageway; and circuit means for individually connecting the four strain gages into different ones of the four arms of a Wheatstone bridge whereby the first pair of strain gages causes the bridge to provide an indication of the fluid pressure within the passageway and the second pair of strain gages provides temperature compensation for the bridge.

Claim 8

A fluid pressure measuring device comprising: a relatively rigid metal piece having an enlarged head portion at one end thereof, a reduced body portion extending from the head portion, and a center passageway extending through the head portion and into the body portion to a point short of the free end of the body portion, the portion of such passageway within the body portion being of cylindrical shape, such body portion having two flat parallel sides lying parallel to the center axis of the passageway and two curved sides interconnecting the two flat sides, such curved sides having a common axis of revolution which coincides with the center axis of the passageway, the width of the body portion transverse to the passageway and parallel to the flat sides being equal to approximately twice the thickness of the body portion between the flat sides and the passageway length within the body portion being equal to approximately twice the thickness of the body portion between the flat sides; a first pair of semiconductor strain gages individually bonded to different ones of the two flat sides above the passageway, each being centered at approximately the midpoint along the passageway length within the body portion and oriented for measuring the strain in a plane transverse to the center axis of the passageway; a second pair of semiconductor strain gages individually bonded to different ones of the two flat sides above the passageway and located nearer the closed end of the passageway than the first pair of strain gages and oriented for measuring the strain in a plane parallel to the center axis of the passageway; and circuit means for individually connecting the four strain gages into different ones of the four arms of a Wheatstone bridge whereby the first pair of strain gages causes the bridge to provide an indication of the fluid pressure within the passageway and the second pair of strain gages provides temperature compensation for the bridge.