WO1991017701A1 - Tubular pressure transducer - Google Patents

Tubular pressure transducer Download PDF

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Publication number
WO1991017701A1
WO1991017701A1 PCT/US1990/001861 US9001861W WO9117701A1 WO 1991017701 A1 WO1991017701 A1 WO 1991017701A1 US 9001861 W US9001861 W US 9001861W WO 9117701 A1 WO9117701 A1 WO 9117701A1
Authority
WO
WIPO (PCT)
Prior art keywords
tube
tubing
stripe
semi
pressure
Prior art date
Application number
PCT/US1990/001861
Other languages
French (fr)
Inventor
Thomas P. Frank
Original Assignee
Medex, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Medex, Inc. filed Critical Medex, Inc.
Priority to PCT/US1990/001861 priority Critical patent/WO1991017701A1/en
Priority to JP90509079A priority patent/JPH05506368A/en
Priority to CA002080025A priority patent/CA2080025A1/en
Priority claimed from CA002080025A external-priority patent/CA2080025A1/en
Publication of WO1991017701A1 publication Critical patent/WO1991017701A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0001—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means
    • G01L9/0002—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means using variations in ohmic resistance
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/021—Measuring pressure in heart or blood vessels
    • A61B5/0215—Measuring pressure in heart or blood vessels by means inserted into the body

Definitions

  • This invention relates to a fluid (gas or liguid) pressure transducer, and particularly to a blood pressure transducer.
  • Blood pressure transducers are known. See, for example, Patent No. 4,576,181 disclosing a dis ⁇ posable blood pressure transducer and Patent No. 4,610,256 disclosing a blood pressure transducer having a disposable dome. Such transducers are com ⁇ plicated, expensive, and somewhat difficult to set up to provide assurance of a complete debubbling, that is, complete removal of air bubbles in the system.
  • Transducers of the type described in the patents referred to above employ a silicon chip forming a pressure sensor, an elastomeric diaphragm on which the chip is mounted, a temperature compensation circuit, a light shield because of the sensitivity of the silicon chip, and a housing mounting all of the foregoing elements in such a way that they can be connected in line with the tubing to which the patient's catheter is connected.
  • the system including the transducer and tubing, is filled with a saline solution that drips slowly through the catheter, the catheter being inserted into the patient's blood vessel.
  • the sensor is electrically connected to a blood pressure monitor presenting a visual display of the patient's blood pressure.
  • An objective of the present invention has been to provide a disposable pressure transducer which is exceedingly simple in its construction, is very inexpensive, and presents virtually no debubbling set up problems.
  • the objective is attained by providing an elastomeric tube doped with conductive particles so that its resistance changes with changes in pressure.
  • the tube section has conductive terminals intimately connected with it at each end.
  • the tube is inserted, as a transducer, in the fluid pressure system to be monitored.
  • the conductive terminals are connected to the monitoring system, preferably through a bridge circuit, the tube forming one part of a Wheatstone bridge.
  • tubular trans ⁇ ducer for example, carbon-doped silicon rubber
  • the internal surface of the tube When used as a blood pressure transducer, as contrasted to an industrial application, the internal surface of the tube must be coated with a dielectric in order to insulate the electrical portion of the total system from the patient. In addition to being a satisfactory dielectric, the coating must also be biocompatible with the fluid system to which the patient is connected.
  • An alternative form of the invention in ⁇ volves the formation of an insulative tubing that does not require a dielectric internal coating.
  • the tubing itself is a dielec ⁇ tric.
  • a stripe or band of sensor material is deposit ⁇ ed on the surface of the tubing to form the sensor.
  • the sensing material could be a conductive polymer, and it could be applied by printing, vapor deposition, etc.
  • Still another alternative consists of pro ⁇ viding a dielectric tube and creating a layer imme ⁇ diately below the surface that is semi-conductive and is formed by ion implantation in accordance with a well known process such as is disclosed in "High Tech Materials Alert," July 1987, page 3.
  • the dielectric nature of the tubing isolates the sensing element, be it printed or ion-implanted, from the fluid within the tube whose pressure is to be measured.
  • Fig. 1 is a diagrammatic view of the pres ⁇ sure monitoring system, the encircled portion being greatly enlarged for illustrative purposes;
  • Fig. 2 is a cross section taken along lines 2-2 of Fig. 1;
  • Fig. 3 is a fragmentary perspective view of an alternative form of the transducer
  • Fig. 4 is a fragmentary perspective view of still another alternative form of the transducer
  • Fig. 5 is a cross-sectional view taken along lines 5-5 of Fig. 4;
  • Fig. 6 is a fragmentary perspective view of still another alternative form of the transducer
  • Fig. 7 is a cross-sectional view taken along lines 7-7 of Fig. 6;
  • Fig. 8 is a cross-sectional view taken along lines 8-8 of Fig. 6.
  • a conventional blood pressure monitoring system includes a catheter 10 for insertion into a patient's blood vessel.
  • Pressure tubing 11 connects the catheter to a transducer 12 of the present invention.
  • a bag of saline solution 13 is connected by a tubing 14 and a flush valve 15 to the transducer.
  • the transducer is a tubular section or tube 16 of an elastomer that has been doped with conductive particles in such a way that its resistance changes in response to pressure applied to it.
  • the tube has, at each end, spigot-type Luer adapters 17.
  • Each adapter has one portion inserted into the end of the tube 16 with the remaining portion projecting from the end of the tubing and adapted to be inserted into the cathe ⁇ ter system tubing to make a liquid-tight connection therewith.
  • two conductive terminals 19 are fastened to the exterior surface of the tube.
  • the contact can simply be a surface contact as by wrapping a wire around the circumference of the tubular section.
  • Those conduc ⁇ tors are connected to the Wheatstone bridge 20.
  • the transducer is a variable resistance element which is connected via a bridge 20 to a monitor circuit. The bridge and monitor circuit convert the changes in resistance to a visual display indicated at 21. Except for the specific transducer, all of the other elements of the circuit are conventional.
  • the tubing is preferably a carbon-doped silicon rubber. It has an internal coating indicated at 25.
  • the coating could be deposited on the interior of the tubing or, alternatively, could be laminated to it by means of a co-extrusion process. It is impor ⁇ tant that the internal coating provide sufficient dielectric protection to provide leakage current pro ⁇ tection and defibrillator withstand. It also must be biocompatible with the fluids passing through it so as to avoid contamination of the patient. It must be able to withstand sterilization processes.
  • tubing which is about .250 inch outside diameter, 0.200 in inside diameter and about 2 inches between conductors provides a good response from the varia ⁇ tions in blood pressure normally found in a patient.
  • the spacing between the conductors can be increased or decreased in order to increase or decrease the resis ⁇ tance between them as required for the particular app ⁇ lication.
  • the tubing dimensions, durometer, material resistivity can also be varied.
  • the variations in blood pres ⁇ sure that are transmitted to the interior of the tubular section 12 cause a pressure to be applied to the tubular section and this alters its resistance.
  • the variations in resistance cause the output from the Wheatstone bridge to vary, thus providing the visual display of the patient's blood pressure.
  • the device is useful with industrial applications.
  • Fig. 3 An alternative from of the invention is illustrated in Fig. 3.
  • tubing indi ⁇ cated at 30 is formed of an insulating polymer.
  • a conductive polymer is deposited in a stripe 31 on the surface of the tubing 30.
  • the conductive polymer could be printed, coated, or vapor deposited onto the surface.
  • variations in pressure within the tubing will be reflected by variations in the resistance between the two conductors 32 of the stripe 31 to provide information at the monitor 21.
  • the stripe may be in the form of a circumferential band extending around a substantial portion of the circumference of the tubing 30.
  • the ion implanta ⁇ tion forms a semi-conductive section whose resistance will vary with changes in pressure in the tubing. It will be in the form of a stripe 41 (Figs. 4, 5), or a band 42 (Figs. 6, 7, 8), as in the previous embodi ⁇ ment. Conductors will connect the implant to a bridge as in the previous embodiments.
  • fluid under varying pressure will cause the insulative tubes to expand and contract, thereby causing said stripe or ion-implanted portion to expand and contract, thereby varying the resistance of the stripe or ion-implanted portion.
  • the variation in resistance is proportional to the variation in pressure and the measurement of it, as, for example, by incorporating it in a Wheatstone bridge, will provide a measurement of pressure and variations in pressure.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Cardiology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Physiology (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

In a blood pressure monitoring system, a transducer (12) which is a conductive rubber tube (16) having conductive terminals (19) at each end. In alternative embodiments, a nonconductive tube has a semiconductive stripe (31) or band or an ion-implanted stripe (41) or band (42) forming the pressure-responsive element.

Description

Tubular Pressure Transducer
This is a continuation-in-part of copending U. S. patent application Serial No. 07/086,613, filed August 18, 1987.
This invention relates to a fluid (gas or liguid) pressure transducer, and particularly to a blood pressure transducer.
Blood pressure transducers are known. See, for example, Patent No. 4,576,181 disclosing a dis¬ posable blood pressure transducer and Patent No. 4,610,256 disclosing a blood pressure transducer having a disposable dome. Such transducers are com¬ plicated, expensive, and somewhat difficult to set up to provide assurance of a complete debubbling, that is, complete removal of air bubbles in the system. Transducers of the type described in the patents referred to above employ a silicon chip forming a pressure sensor, an elastomeric diaphragm on which the chip is mounted, a temperature compensation circuit, a light shield because of the sensitivity of the silicon chip, and a housing mounting all of the foregoing elements in such a way that they can be connected in line with the tubing to which the patient's catheter is connected. The system, including the transducer and tubing, is filled with a saline solution that drips slowly through the catheter, the catheter being inserted into the patient's blood vessel. Thus, the pressure in the blood vessel is transmitted directly via the saline solution through the tubing to the transducer. The sensor is electrically connected to a blood pressure monitor presenting a visual display of the patient's blood pressure.
Less complex in structure is a tubular sensor of Patent No. 4,600,855. That system, however, reguires a special tube and piezoelectric film sur¬ rounding the tube. A complex electric circuit is employed to energize the piezoelectric film to cause the tube to resonate and to monitor the frequencies of resonance.
An objective of the present invention has been to provide a disposable pressure transducer which is exceedingly simple in its construction, is very inexpensive, and presents virtually no debubbling set up problems.
The objective is attained by providing an elastomeric tube doped with conductive particles so that its resistance changes with changes in pressure. The tube section has conductive terminals intimately connected with it at each end. The tube is inserted, as a transducer, in the fluid pressure system to be monitored. The conductive terminals are connected to the monitoring system, preferably through a bridge circuit, the tube forming one part of a Wheatstone bridge.
It has been found that such a tubular trans¬ ducer, for example, carbon-doped silicon rubber, pro¬ vides an excellent monitor of the pressure variations within the fluid system.
When used as a blood pressure transducer, as contrasted to an industrial application, the internal surface of the tube must be coated with a dielectric in order to insulate the electrical portion of the total system from the patient. In addition to being a satisfactory dielectric, the coating must also be biocompatible with the fluid system to which the patient is connected.
An alternative form of the invention in¬ volves the formation of an insulative tubing that does not require a dielectric internal coating. In this form of the invention, the tubing itself is a dielec¬ tric. A stripe or band of sensor material is deposit¬ ed on the surface of the tubing to form the sensor. The sensing material could be a conductive polymer, and it could be applied by printing, vapor deposition, etc. Still another alternative consists of pro¬ viding a dielectric tube and creating a layer imme¬ diately below the surface that is semi-conductive and is formed by ion implantation in accordance with a well known process such as is disclosed in "High Tech Materials Alert," July 1987, page 3. In this embodi¬ ment, as well as the former embodiment, the dielectric nature of the tubing isolates the sensing element, be it printed or ion-implanted, from the fluid within the tube whose pressure is to be measured.
Obviously, the straight tubular section in series with the tube connected to the patient's catheter introduces no problem of debubbling. Thus, bubbles which could damp the electrical signals are eliminated as well as any hazardous bubbles that might enter the patient's circulatory system and cause embolism.
The several features of the invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Fig. 1 is a diagrammatic view of the pres¬ sure monitoring system, the encircled portion being greatly enlarged for illustrative purposes;
Fig. 2 is a cross section taken along lines 2-2 of Fig. 1;
Fig. 3 is a fragmentary perspective view of an alternative form of the transducer; Fig. 4 is a fragmentary perspective view of still another alternative form of the transducer;
Fig. 5 is a cross-sectional view taken along lines 5-5 of Fig. 4;
Fig. 6 is a fragmentary perspective view of still another alternative form of the transducer;
Fig. 7 is a cross-sectional view taken along lines 7-7 of Fig. 6;
Fig. 8 is a cross-sectional view taken along lines 8-8 of Fig. 6.
Referring to Fig. 1, a conventional blood pressure monitoring system is shown. It includes a catheter 10 for insertion into a patient's blood vessel. Pressure tubing 11 connects the catheter to a transducer 12 of the present invention. A bag of saline solution 13 is connected by a tubing 14 and a flush valve 15 to the transducer.
The transducer is a tubular section or tube 16 of an elastomer that has been doped with conductive particles in such a way that its resistance changes in response to pressure applied to it. The tube has, at each end, spigot-type Luer adapters 17. Each adapter has one portion inserted into the end of the tube 16 with the remaining portion projecting from the end of the tubing and adapted to be inserted into the cathe¬ ter system tubing to make a liquid-tight connection therewith. Between the ends of the tubular section 12, two conductive terminals 19 are fastened to the exterior surface of the tube. The contact can simply be a surface contact as by wrapping a wire around the circumference of the tubular section. Those conduc¬ tors are connected to the Wheatstone bridge 20. The transducer is a variable resistance element which is connected via a bridge 20 to a monitor circuit. The bridge and monitor circuit convert the changes in resistance to a visual display indicated at 21. Except for the specific transducer, all of the other elements of the circuit are conventional.
The tubing is preferably a carbon-doped silicon rubber. It has an internal coating indicated at 25. The coating could be deposited on the interior of the tubing or, alternatively, could be laminated to it by means of a co-extrusion process. It is impor¬ tant that the internal coating provide sufficient dielectric protection to provide leakage current pro¬ tection and defibrillator withstand. It also must be biocompatible with the fluids passing through it so as to avoid contamination of the patient. It must be able to withstand sterilization processes.
It has been found that a short length of tubing which is about .250 inch outside diameter, 0.200 in inside diameter and about 2 inches between conductors provides a good response from the varia¬ tions in blood pressure normally found in a patient. The spacing between the conductors can be increased or decreased in order to increase or decrease the resis¬ tance between them as required for the particular app¬ lication. The tubing dimensions, durometer, material resistivity can also be varied.
In operation, the variations in blood pres¬ sure that are transmitted to the interior of the tubular section 12 cause a pressure to be applied to the tubular section and this alters its resistance. The variations in resistance cause the output from the Wheatstone bridge to vary, thus providing the visual display of the patient's blood pressure.
With suitable modifications, the device is useful with industrial applications.
An alternative from of the invention is illustrated in Fig. 3. There standard tubing indi¬ cated at 30 is formed of an insulating polymer. A conductive polymer is deposited in a stripe 31 on the surface of the tubing 30. The conductive polymer could be printed, coated, or vapor deposited onto the surface. When that tubing or a portion of it is placed in a fluid circuit of the type shown in Fig. 1, for example, with conductors 32 connecting the stripe 31 to the Wheatstone bridge 20, variations in pressure within the tubing will be reflected by variations in the resistance between the two conductors 32 of the stripe 31 to provide information at the monitor 21. Instead of a longitudinally-extending stripe 31, the stripe may be in the form of a circumferential band extending around a substantial portion of the circumference of the tubing 30.
Another alternative that consists of forming the sensing element by an ion implantation immediately beneath the surface of the tubing. The ion implanta¬ tion forms a semi-conductive section whose resistance will vary with changes in pressure in the tubing. It will be in the form of a stripe 41 (Figs. 4, 5), or a band 42 (Figs. 6, 7, 8), as in the previous embodi¬ ment. Conductors will connect the implant to a bridge as in the previous embodiments.
In the embodiments of Figs. 3-8, fluid under varying pressure will cause the insulative tubes to expand and contract, thereby causing said stripe or ion-implanted portion to expand and contract, thereby varying the resistance of the stripe or ion-implanted portion. The variation in resistance is proportional to the variation in pressure and the measurement of it, as, for example, by incorporating it in a Wheatstone bridge, will provide a measurement of pressure and variations in pressure.
From the above disclosure of the general principles of the present invention and the preceding detailed description of a preferred embodiment, those skilled in the art will readily comprehend the various modifications to which the present invention is susceptible. Therefore, I desire to be limited only by the scope of the following claims and eguivalents thereof:
I claim:

Claims

(1) A fluid pressure transducer comprising, a resilient insulative tube, a semi-conductive stripe deposited on said tube, and conductors connected to said stripe, whereby fluid under varying pressure will cause said insulative tube to expand and contract, thereby causing said stripe to expand and contract, thereby varying the resistance of the stripe as a reflection of the variation of fluid pressure.
(2) A fluid pressure transducer comprising, a resilient insulative tube, ions implanted in the surface of at least a portion of said tube to create a semi-conductive portion of said tube, and conductors connected to the semi¬ conductive portion of said tube, whereby fluid under varying pressure will cause said insulative tube to expand and contract, thereby causing the ion-implanted portion of the tube to expand and contract, thereby varying the resistance of the ion-implanted portion of the tube. (3) A fluid pressure transducer comprising, a resilient insulative tubing, a semi-conductive band deposited on and partially surrounding a section of tubing, and circumferentially spaced conductors connected to said semi-conductive band, whereby fluid under varying pressure will cause said insulative tube to expand and contract, thereby causing said semi-conductive band to expand and contract, thereby varying the resistance of the semi-conductive band.
PCT/US1990/001861 1990-05-11 1990-05-11 Tubular pressure transducer WO1991017701A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/US1990/001861 WO1991017701A1 (en) 1990-05-11 1990-05-11 Tubular pressure transducer
JP90509079A JPH05506368A (en) 1990-05-11 1990-05-11 tubular pressure transducer
CA002080025A CA2080025A1 (en) 1990-05-11 1990-05-11 Tubular pressure transducer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PCT/US1990/001861 WO1991017701A1 (en) 1990-05-11 1990-05-11 Tubular pressure transducer
CA002080025A CA2080025A1 (en) 1990-05-11 1990-05-11 Tubular pressure transducer

Publications (1)

Publication Number Publication Date
WO1991017701A1 true WO1991017701A1 (en) 1991-11-28

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1990/001861 WO1991017701A1 (en) 1990-05-11 1990-05-11 Tubular pressure transducer

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995006205A1 (en) * 1993-08-23 1995-03-02 W.L. Gore & Associates, Inc. Pre-failure warning pump diaphragm
US5581019A (en) * 1992-07-16 1996-12-03 W. L. Gore & Associates, Inc. Gasket/insertable member and method for making and using same
EP1156214A1 (en) * 2000-05-18 2001-11-21 Firma Carl Freudenberg Control system for Membrane pump
EP1156215A1 (en) * 2000-05-18 2001-11-21 Firma Carl Freudenberg Control system for pump membrane
EP2876421A1 (en) * 2013-11-25 2015-05-27 ContiTech AG Elastomer hollow body, in particular elastomer hose, having a sensor element for measuring pressure and method for the same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3149492A (en) * 1961-03-06 1964-09-22 Astra Inc Fluid pressure gauge
US3957037A (en) * 1975-02-24 1976-05-18 Nasa Readout electrode assembly for measuring biological impedance
US4027659A (en) * 1975-11-21 1977-06-07 Krandex Corporation Radiographic opaque and conductive stripped medical tubes
US4420980A (en) * 1980-10-06 1983-12-20 Siemens Aktiengesellschaft Arrangement for measuring the pressure in cylindrical cavities
US4425526A (en) * 1981-10-29 1984-01-10 The Perkin-Elmer Corp. Method of making electrical connections to thin film coatings and the electrical connector formed thereby
US4484479A (en) * 1978-04-05 1984-11-27 Richard Eckhardt Gas flow metering
US4706501A (en) * 1980-11-21 1987-11-17 Imperial Chemical Industries Plc Detection of step charges of pressure in vessels and apparatus therefor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3149492A (en) * 1961-03-06 1964-09-22 Astra Inc Fluid pressure gauge
US3957037A (en) * 1975-02-24 1976-05-18 Nasa Readout electrode assembly for measuring biological impedance
US4027659A (en) * 1975-11-21 1977-06-07 Krandex Corporation Radiographic opaque and conductive stripped medical tubes
US4484479A (en) * 1978-04-05 1984-11-27 Richard Eckhardt Gas flow metering
US4420980A (en) * 1980-10-06 1983-12-20 Siemens Aktiengesellschaft Arrangement for measuring the pressure in cylindrical cavities
US4706501A (en) * 1980-11-21 1987-11-17 Imperial Chemical Industries Plc Detection of step charges of pressure in vessels and apparatus therefor
US4425526A (en) * 1981-10-29 1984-01-10 The Perkin-Elmer Corp. Method of making electrical connections to thin film coatings and the electrical connector formed thereby

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5581019A (en) * 1992-07-16 1996-12-03 W. L. Gore & Associates, Inc. Gasket/insertable member and method for making and using same
WO1995006205A1 (en) * 1993-08-23 1995-03-02 W.L. Gore & Associates, Inc. Pre-failure warning pump diaphragm
EP1156214A1 (en) * 2000-05-18 2001-11-21 Firma Carl Freudenberg Control system for Membrane pump
EP1156215A1 (en) * 2000-05-18 2001-11-21 Firma Carl Freudenberg Control system for pump membrane
WO2001088375A1 (en) * 2000-05-18 2001-11-22 Carl Freudenberg Kg Device for monitoring the integrity of a membrane
WO2001088376A1 (en) * 2000-05-18 2001-11-22 Carl Freudenberg Kg Method and device for detecting pump operation parameters of a diaphragm delivery unit
EP2876421A1 (en) * 2013-11-25 2015-05-27 ContiTech AG Elastomer hollow body, in particular elastomer hose, having a sensor element for measuring pressure and method for the same

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