Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
  • G01L13/02—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements
  • G01L13/025—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using diaphragms
  • G01L13/026—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using diaphragms involving double diaphragm
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L15/00—Devices or apparatus for measuring two or more fluid pressure values simultaneously
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
  • G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
  • G01L19/0618—Overload protection
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
  • G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
  • G01L19/0627—Protection against aggressive medium in general
  • G01L19/0645—Protection against aggressive medium in general using isolation membranes, specially adapted for protection
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
  • G01L19/14—Housings
  • G01L19/142—Multiple part housings

Definitions

• the invention relates to a differential pressure transducer containing a measurement structure filled with a manometer liquid.
• Differential pressure transmitters in which a silicon sensing element is subjected to two measured pressures are generally known.
• the drawback of such silicon structure is that it is subject to an individual error manifesting itself as absence of long-term stability, resulting in gradual change in the signal (bridge imbalance voltage) not resulting from change in pressure acting upon such a structure.
• Such effect is particularly troubling in transducers used for measurement of very small pressure differences, for which changes in the measurement signal resulting from sensor instability are distinctly visible on background of signals resulting from changes in the measured pressures.
• the transducer includes a pressure sensor and two seal-tight measurement zones filled with a manometer liquid acting upon the sensing element on both its sides.
• the measurement zones are isolated by an overload diaphragm and separated from the sources of pressures measured using the measurement diaphragms. Isolation of the sensor with the manometer liquid and measurement diaphragms from media, the pressures of which are to be measured, allows such transducer to find application in measuring pressure differences of a wide spectrum of media, including aggressive media.
• Use of an overload diaphragm protects the transducer from failure resulting from e.g. uncontrolled increase in the impact pressure. Disclosure of Invention
• the object of this invention was to develop a pressure transducer ensuring stable over time readout of the measured pressure differences.
• a differential pressure transducer including a pressure sensor as well as a first and a second seal-tight measurement zone filled with manometer liquid acting upon sensing elements of the pressure sensor.
• the measurement zones are separated with an overload diaphragm and separated from the sources of measured pressures with a first and a second measurement diaphragm, respectively.
• the invention consists in that the pressure sensor of the transducer has a first and a second measurement chamber, each of the measurement chambers has a first and a second inlet for the manometer liquid separated from each other with the sensing element.
• the first measurement zone is connected with the first inlet of the first measurement chamber and with the second inlet of the second measurement chamber, while the second measurement zone is connected with the first inlet of the second measurement chamber and with the second inlet of the first measurement chamber.
• the measurement zone is formed by cavities and channels in two cylinders coaxially adjacent to each other with first bases, and between the cylinders an overload diaphragm is circumferentially clamped.
• the measurement diaphragms are located on second bases of the cylinders opposite in relation to the overload diaphragm.
• the measurement chambers have the form of a set of three coaxial cylinders with channels and cavities, wherein the sensing elements are located in cavities of extreme cylinders adjacent to the central cylinder.
• connections of the measurement zones with the measurement chambers constitute capillaries.
• the transducer according to the invention effectively minimizes the impact on the measurement errors resulting from instability of sensory structures, making it possible to make a measurement device for very small pressure ranges, with accuracy and zero shift error for static pressure far less than before as well as with better long-term stability.
• Fig.1 of the drawing presents a side view of the differential transducer, whereas Fig.2 presents a horizontal cross-section through the same transducer.
• Fig.3, Fig. 4 and Fig.5 present vertical cross- sections of the same transducer.
• Fig.6 presents a simplified view of the transducer sensor and Fig.7 presents its electric scheme.
• the base of the transducer according to the invention is formed by a cylindrical left bed 1 and a cylindrical right bed 2 each having diameter of 38 mm, made of stainless steel.
• the bed 1 and the bed 2 have a cavity 3 for the overload membrane 4, which is mounted in the transducer by pressing it between the bed 1 and the bed 2 and connecting the beds with a circumferential weld 5.
• the beds 1 and 2 possess cavities 6 for known measurement diaphragms T and 7" having diameter of 32 mm.
• Each diaphragm 7 is pressed to its bed (1 and 2, respectively) with a ring circumferentially welded to the bed.
• Pressures to be measured by the transducer are led in by an known way to the external surfaces of the measurement diaphragms. Cavities 3 and 6 are connected with each other through channels 8 and filled with silicon oil constituting the manometer liquid of the transducer.
• a pipe housing 9 for the pressure sensor is connected with base of the transducer.
• the pressure sensor constitute two silicon differential sensing elements 1 0 and 1 1 , a central cylindrical connector 1 2 of diameter 1 6 mm and made of stainless steel, and two pass-through cylinders 1 3 and 14 having the same diameters and made of the same material, permanently fixed to the connector 1 2.
• each other cavities in the connector 1 2 and in the pass-through cylinders 1 3 and 14 form two measurement chambers 1 5 and 16 in which said sensing elements 1 0 and 1 1 are mounted.
• Each of the measurement chambers 1 5 and 1 6 possess two inlets 1 7, 1 9, and 1 8, 20 respectively, leading the manometer liquid to both sides of the sensing elements 1 0 and 1 1 .
• Inlets 1 7, 1 8, 1 9 and 20 of the measurement chambers 1 5 and 1 6 are interconnected with metal capillaries 21 having diameter of 1 mm.
• the capillaries 21 also connect the pressure sensor with external zones in the transducer base.
• the measurement chambers 15 and 16, capillaries 21 and the internal spaces of the bed 1 and 2 constitute two measurement zones seal- tightly filled with manometer liquid and separated from each other with the overload membrane 4.
• First inlet 17 of the first measurement chamber 15 is connected with the second inlet 20 of the second measurement chamber 16 and with part of the measurement zone situated in vicinity of the measurement diaphragm 7" to which the pressure P 2 is led.
• the second inlet 19 of the first measurement chamber 15 is connected with the first inlet 18 of the second measurement chamber 16 and with part of the measurement zone situated in vicinity of the measurement diaphragm T to which the pressure Pi is led.
• Each sensing element 10 and 1 1 comprises an integrated Wheatstone bridge, the outlets of which are connected with wires 22 passing seal-tightly through pass- through cylinders 13 and 14 and lead to electronic circuit board 23 which, in turn is connected with an exit cable 24 of the transducer.
• Figure 7 shows that the Wheatstone bridges have been connected in parallel. The connection is effected on circuit board 23 by way of printed tracks to which the wires 22 are connected.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Fluid Pressure (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=55586346

Family Applications (1)

Country Status (3)

Citations (3)

• 2015
  • 2015-02-13 PL PL411269A patent/PL227812B1/pl unknown
• 2016
  • 2016-02-13 EP EP16710811.7A patent/EP3256832A1/en not_active Withdrawn
  • 2016-02-13 WO PCT/IB2016/050777 patent/WO2016128950A1/en active Application Filing

Patent Citations (3)

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