Patent Application
20240377274
The present invention relates to a device and retrofit kit, for measuring the pressure of a material. The invention is especially useful for measuring the pressure of a flowing substance.
Pressure sensors are typically used in pipes and conduits to measure the absolute or relative pressure of a fluid or gas in the pipe. Measurement of the pressure in the pipe is critical for monitoring pipe integrity, and fluid/gas flow. The pressure is measured either during flow, or in the absence of flow.
U.S. Pat. No. 5,212,989 describes a pressure sensor used in an automobile internal combustion engine. The pressure sensor includes a flush mounted element on the inner side of a pipe. The flush mounted element includes a flexible member, and a non-compressible fluid, in contact with the flexible member and the pressure sensor. The flexible member deforms under the pressure of the liquid in the pipe. The non-compressible liquid transmits the pressure to the pressure sensor, which detects the pressure of the non-compressible fluid.
Reference is made to Prior Art
Over time, especially when turbid fluids are measured, sediment tends to build-up on the external diaphragm (107) such as that of the U.S. Pat. No. 5,212,989 sensor or similar sensors. Deposits that collect upon the flush-mounted flexible member, reduce its functionality and reliability. Non-limiting examples of turbid materials being measured, that tend towards sediment deposit, include sludge, oils, solar fluids, and other particulate materials.
The need exists for an improved pressure sensor for pressure measurement, that may be used in any liquid, gas, or viscous material. The pressure sensor should prevent residue buildup on the external diaphragm, when used to measure pressure of materials that are corrosive, or are turbid (containing sludge or contaminants).
The present invention overcomes the limitations of the existing art. The invention provides pressure sensors and retrofit kits for pressure sensors, that continuously function even in turbid environments; and prevent scum accumulation that would interfere with pressure measurement. These and other advantages of the invention are described in the Detailed Description of the invention that follows.
In a general overview of the invention, the present invention provides a pressure sensor, and a retrofit kit for a pressure sensor, that resolve the prior art problem of residue buildup on the external diaphragm that contacts the material being measured; thus, the invention is capable of functioning over an extended length of time.
Optionally, said lengthened elastomeric conduit is formed of a material selected from: nitrile rubber (NBR), silicone, EPDM rubber, HNBR, and Viton®.
Further, in some cases the elastomeric conduit is formed of a flexible material such that movement of said elastomeric conduit in response to flow of a material being measured, prevents residue buildup upon said external diaphragm.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.
In the present invention, the term “pressure measuring mechanism” used in reference to measurement of the deformation of an internal diaphragm, refers to: means that are used to analyze the degree of deformation of the internal diaphragm, and to relate the measured deformation of the internal diaphragm, to the pressure of a substance being measured. Non-limiting examples include: optical, electronic, or mechanical means. The pressure sensing element may be a Bourdon tube, a diaphragm, a capsule, or a set of bellows, which will change shape in response to the pressure of the region in question. The deflection of the pressure sensing element may be read by a linkage connected to a needle, or it may be read by a secondary transducer. Electronic measuring, may be done for instance, using any of the following gauges: a metal strain gauge, piezoresistive strain gauge, piezoresistive silicon pressure sensor, a capacitive gauge, magnetic piezoelectric, optical, potentiometric, and resonant gauges. Specific commercial non-limiting examples are found in the Examples hereinbelow.
In the present invention, the term “non-compressible fluid” refers to a fluid with constant density, or the change in density with pressure, is so small as to be considered negligible. Non-limiting examples include water, hydraulic fluids, and glycerin.
In the present invention, the term “material”, used in relation to a substance undergoing pressure measurement, refers to any media, in various physical phases. Non-limiting examples include: gas, fluid, and viscous materials. The term “substance” is used interchangeably with the term “material”.
The present invention is illustrated by way of example in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the present invention. There is no intention to limit the invention to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The invention provides a pressure sensor, and a retrofit kit for a pressure sensor, that resolve the prior art problem of residue buildup on the external diaphragm that contacts the material being measured; thus, the invention is capable of functioning over an extended length of time.
In the following description, the invention is described in use to measure the pressure of a gas or a fluid flowing in a pipe, as these are common uses for pressure gauges. There is no intention to limit the scope of the invention to these uses, rather the invention may be used to measure any material in any phase of being, and in any location.
In a general overview, in order to prevent residue buildup from the substance being measured, on the external diaphragm, the invention provides a lengthened elastomeric conduit, which protrudes into the fluid/gas pipe. The elastomeric conduit is filled with a non-compressible fluid, and terminates in an external diaphragm. Without being bound by theory, the elastomeric nature of the conduit allows free movement of the conduit, in response to flow in the pipe, and thus dislodges any residue that initially contacts the external diaphragm. The invention is provided as a pressure sensor; or as a kit for retrofitting a prior art pressure sensor.
In one embodiment, the elastomeric conduit is angled compared to the direction of flow of the material being measured. The angle further prevents residue deposit.
Referring now in detail to
Mounting (201) connects rigid external tube (105) to lengthened elastomeric conduit (203) which extends into pipe (109) containing a fluid (111) to be measured. The lengthened elastomeric conduit (203) terminates in the external diaphragm (107). A non-compressible liquid (113) is contained between the internal diaphragm (103) and the external diaphragm (107). Any pressure exerted on the external diaphragm, by the fluid or gas (111) being measured in the pipe (109), will be transferred by the non-compressible fluid (113) to the internal diaphragm (103).
The internal diaphragm (103) deformation is then measured using the pressure measuring mechanism (150) which is any of: optical, electronic, or mechanical, as are well known in the art. The pressure being measured, for the fluid or gas (111) flowing in a pipe (109), is related to the measured deformation of the internal diaphragm (103).
As shown in
In one embodiment, in order to obtain a constant angle (170), mounting (201) is rigid, and extends at an angle into the pipe (109) at the point of attachment to the elastomer. Alternatively, or additionally, the flow of fluid or gas in the pipe (109) past the lengthened elastomeric conduit (203), generates the angle (170) by sweeping the elastomeric conduit (203) in the direction of flow.
The elastomer chosen for the lengthened elastomeric conduit (203), as well as the thickness used, may effect the angle of the conduit (203).
Presently preferred materials for the lengthened elastomeric conduit (203), include the non-limiting examples: NBR (nitrile rubber), silicone, EPDM rubber (ethylene propylene diene monomer rubber), HNBR (hydrogenated nitrile rubber), and Viton® by
DuPont. Any natural or synthetic polymer that is viscoelastic, may be utilized as the elastomer.
The lengthened elastomeric conduit (203) protrudes into the pipe (109) and may be fully or partially immersed in the fluid (111).
In an alternative embodiment the difference between the angle and direction of flow is equal or less than 90°.
In one alternative embodiment, the mounting (201) is dynamically configured: In one example, the mounting (201) has an internal spring mechanism to allow freedom of movement after its installation. Optionally, the mounting is formed of a material having inherent flexibility. Flow of a material (111) being measured, exerts a force on the lengthened elastomeric conduit (203), creating the angle (205) between the lengthened elastomeric conduit (203) and the pipe (109). As the rate of the fluid/gas (111) flow changes in the pipe, the angle (205) will change.
In some embodiments, the mounting (201) is either rigid at a defined angle (205), or is flexible around a defined angle (205). In a further embodiment, the defined angle can be any angle in range of 0°to 180°, and the flexibility around an angle (205) can range from any of but not limited to; +/−1°; +/−5°; +/−10°; or smaller than +/−25°.
Deformation of the flexible interface (301) by the fluid (111) being measured, is transmitted via the non-compressible fluid 113 to deformation of the internal diaphragm (103), which is measured by the pressure measuring mechanism (150).
In use of any of the embodiments of the invention, it may be necessary to adjust the pressure of the non-compressible fluid (113) after assembly of the fluid pressure sensor body (101) on a pipe (109). The base pressure of the non-compressible fluid (113) in the absence of a fluid in the pipe (109), may be set by any means: electrical, mechanical, fluidic actuation and a piston or pump mechanism. The base pressure may be set at any time, such as: prior to installation of pressure sensor on pipe (109), immediately after installation of pressure sensor on pipe (109), periodically after installation to remove debris by mechanical deformation of one or more flexible interfaces (301), and as a corrective measure after installation to remove debris by mechanical deformation of one or more flexible interfaces (301).
Referring to
Mounting (201) may be of the threaded screw variety, configured to mate with pipe (109) and with rigid external tube (105) of Prior art pressure sensor (shown in
Referring to
Referring to
Referring to
A retrofit kit described in relation to
The Baumer Pressure gauge selected includes an overpressure safety, with an open lower flange. The gauge measures pressure ranges of, 0.4 to 25 bar (for flange ø 100 mm) or 60 to 250 mbar (for flange ø 150 mm). The dampening liquid is glycerin 86%. The retrofitted pressure gauge, after installation of kit, was able to accurately detect the pressure of sewage in a central municipal pipe, without clogging. Visual examination after several weeks of use did not detect residue buildup upon the external diaphragm.
The retrofit kit described in relation to
Kit included lengthened elastomeric conduit made of silicone, prefilled with a non-compressible fluid, and stainless-steel threaded screw type mounting. O-rings were utilized to seal mounting to a fluid-flow pipe containing a fluid to be measured.
A retrofit kit described in relation to
Without being bound by theory, when measuring the pressure in the pipe, in addition to applying pressure on the fluid pressure sensor elements protruding into the pipe, the fluid flow also imparts a force (F) on the fluid pressure sensor elements protruding into the pipe. As a result of the force (F) action, the fluid pressure elements may experience a local or global movement. A local movement implies a local deformation of one or more of the immersed elements of the pressure sensor, and a global movement implies a movement of any of the elements of the fluid pressure sensor. Resonance may occur in the lengthened elastomeric conduit, or in the external diaphragm, due to the interaction between the masses (m), and the spring constants (k), where the resonance frequency (f) is given by
In an additional embodiment, one or more of the elements of the pressure sensor protruding into the pipe are constructed have a mass and or spring constant so at least one resonance frequency which prevents buildup of residue on the one or more pressure sensor elements protruding into the pipe and especially any of the flexible interfaces or external diaphragm. The long-term reliability of the pressure sensor measurement is enhanced by reduction of residue buildup due to the resonance mechanical vibrations.
In a further embodiment the external tube includes one or more hydro-dynamic elements configured to generate a force from the fluid flow. The hydro-dynamic elements enhance the vibrations generated in the external tube from the fluid flow.
In summary, the pressure sensors and retrofit kits of the invention, continuously function even in turbid fluids; and prevent scum accumulation on the lengthened elastomeric conduit and external diaphragm, that would interfere with pressure measurement. The functionality and reliability of the pressure measurement is thus considerably extended.
Having described the invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, as further modifications will now become apparent to those skilled in the art, and it is intended to cover such modifications as are within the scope of the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IL2022/050798 | 7/25/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63225582 | Jul 2021 | US |
