US-12618734-B2 - Differential pressure measuring device for oil test

Abstract

A pressure measuring device includes a pressure gauge having a pressure measuring member, at least one connection line which connects the pressure gauge to a measured media source, a connection block which is fluidically connected to the pressure gauge, a heating element and/or cooling element which controls a temperature of the connection block, and at least one closable vent hole which is arranged in the connection block. A section of the at least one connection line which is connected to the pressure measuring member is arranged in the connection block. The at least one closable vent hole is arranged to branch off from the at least one connection line in an ascending manner and to open above the at least one connection line.

Inventors

• Wolfgang Sailer

Assignees

• AVL LIST GMBH

Dates

Publication Date

20260505

Application Date

20211110

Priority Date

20201111

Claims (20)

1. 1 . A pressure measuring device comprising: a pressure gauge comprising a pressure measuring member; at least one connection line which is configured to connect the pressure gauge to a measured media source; a connection block which is fluidically connected to the pressure gauge, the connection block being configured so that a section of the at least one connection line which is connected to the pressure measuring member is arranged therein; at least one of a heating element and a cooling element which is/are configured to control a temperature of the connection block; and at least one vent hole which is configured to be closable and which is arranged in the connection block, the at least one vent hole being arranged to branch off from the at least one connection line in an ascending manner and to open above the at least one connection line.
2. 2 . The pressure measuring device as recited in claim 1 , wherein the at least one of the heating element and the cooling element is/are further configured control the temperature of the connection block to a constant temperature.
3. 3 . The pressure measuring device as recited in claim 1 , wherein the at least one connection line extends horizontally.
4. 4 . The pressure measuring device as recited in claim 1 , wherein the connection block is made of a material having a thermal conductivity of more than 100 W/mK.
5. 5 . The pressure measuring device as recited in claim 1 , further comprising: a pressure gauge housing which is configured to attach the pressure gauge to the connection block, wherein, the connection block comprises a connection opening arranged therein via which the pressure gage is fluidically connected to the connection block.
6. 6 . The pressure measuring device as recited in claim 5 , wherein the connection block is provided as, a first connection block part which comprises the connection opening to the pressure gauge, and a second connection block part which comprises a connection to the at least one connection line.
7. 7 . The pressure measuring device as recited in claim 5 , wherein the at least one vent hole is further configured open to the at least one connection line in a region of the connection opening of the at least one connection line to the pressure gauge.
8. 8 . The pressure measuring device as recited in claim 5 , further comprising: an outer housing which is connected to the connection block and which is arranged to surround the pressure gauge and to have the pressure gauge be arranged therein.
9. 9 . The pressure measuring device as recited in claim 8 , wherein the outer housing is made of a material having a thermal conductivity of more than 100 W/mK.
10. 10 . The pressure measuring device as recited in claim 8 , wherein at least one of the outer housing and the connection block comprises/comprise a reflective surface which is arranged to face outwards.
11. 11 . The pressure measuring device as recited in claim 8 , wherein, the outer housing comprises side walls, the connection block comprises side surfaces, the outer housing and the connection block are configured to surround the pressure gauge on all sides thereof, and the side walls of the outer housing extend along the side surfaces of the connection block.
12. 12 . The pressure measuring device as recited in claim 11 , wherein webs are formed on a side surface of one of the side surfaces of the connection block which faces an interior of the outer housing.
13. 13 . The pressure measuring device as recited in claim 8 , further comprising: an insulation which is configured to surround the outer housing.
14. 14 . The pressure measuring device as recited in claim 8 , wherein, the pressure gauge is a pressure transmitter which comprises a diaphragm as a pressure measuring member, and the diaphragm is pressurized with a fluid from the at least one connection line.
15. 15 . The pressure measuring device as recited claim 14 , wherein a diameter of the connection opening to the pressure transmitter in the connection block is at least as large as a diameter of the diaphragm.
16. 16 . The pressure measuring device as recited in claim 8 , wherein, the at least one connection line is provided as a first connection line and a second connection line each of which comprise a section which is connected to the pressure gauge, the pressure gauge is a differential pressure gauge, and the section of the first connection line which connected to the pressure gauge and the section of the second connection line which is connected to the pressure gauge are each formed in the connection block.
17. 17 . The pressure measuring device as recited in claim 16 , wherein, the differential pressure gauge is a differential pressure transmitter which comprises a first pressure measuring member and a second pressure measuring member, the first pressure measuring member is pressurized with a fluid from the first connection line, and the second pressure measuring member is pressurized with a medium from the second connection line.
18. 18 . The pressure measuring device as recited in claim 17 , wherein the first pressure measuring member and the second pressure measuring member are each arranged at a height which is the same.
19. 19 . The pressure measuring device as recited in claim 18 , further comprising: a temperature sensor which is configured to control the temperature of the connection block with respect to the height, the temperature sensor being arranged centrally with respect to pressure measuring member.
20. 20 . The pressure measuring device as recited in claim 19 , wherein, the temperature sensor is arranged centrically to the pressure measuring member, or the temperature sensor is arranged symmetrically between the first pressure measuring member and the second pressure measuring member.

Description

CROSS REFERENCE TO PRIOR APPLICATIONS This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/AT2021/060426, filed on Nov. 10, 2021 and which claims benefit to Austrian Patent Application No. A50973/2020, filed on Nov. 11, 2020. The International Application was published in German on May 19, 2022 as WO 2022/099341 A2 under PCT Article 21(2). FIELD The present invention relates to a pressure measuring device with a pressure gauge having a pressure measuring element and a connection line via which the pressure gauge is connected with a measured media source. BACKGROUND Such pressure measuring devices are used, for example, for measuring an oil pressure or a differential pressure of fluids in test stands. The measurement of a hydrostatic pressure in an oil sump of a test bench should in particular be mentioned. It is also known to determine a differential pressure between the oil in the oil sump and the gas in the part of the oil sump which is not filled with oil via pressure transmitter systems in order to determine the filling level of the oil sump. A differential pressure in the piping system of a test stand can also be used to determine oil consumption so that a measurement medium source is understood to mean both pipes in which there is a flow as well as containers or tanks in which the measurement medium is essentially stationary, i.e., only a small mass exchange takes place. Either sensors or, in the case of most pressure transmitters, diaphragms serve as pressure measuring elements. Due to the strong vibrations that occur for pressure measurement, pressure transmitter systems are mostly used for measurement in which the process pressure acts via a diaphragm on a liquid in a capillary tube, which then deflects the measuring body of the pressure transmitter, which serves as a scale for determining the process pressure. This is accordingly a closed measuring system in which no exchange of the fluid acting on the measuring body exists. It has, however, been found that with rapid temperature changes and high temperatures, that the measurement results of such a system cause errors in the pressure measurement due to the thermal expansion of the fluid in the pressure transmitting system due to the changing density of the fluid. Although attempts are made to compensate these errors mostly using software-based compensation methods, the results are usually not satisfactory since measurement accuracies of up to 0.5 Pa are required. The previously described embodiments accordingly have the disadvantage that a temperature influence on the measuring devices cannot be eliminated, in particular since the temperatures of the measuring medium do not correspond to the temperatures of the fluid at the measuring body. SUMMARY An aspect of the present invention is therefore to provide a pressure measuring device which provides exact measuring results independent of the temperature variation of the measuring medium. In an embodiment, the present invention provides a pressure measuring device which includes a pressure gauge comprising a pressure measuring member, at least one connection line which is configured to connect the pressure gauge to a measured media source, a connection block which is fluidically connected to the pressure gauge, at least one of a heating element and a cooling element which is/are configured to control a temperature of the connection block, and at least one vent hole which is configured to be closable and which is arranged in the connection block. The connection block is configured so that a section of the at least one connection line which is connected to the pressure measuring member is arranged therein. The at least one vent hole is arranged to branch off from the at least one connection line in an ascending manner and to open above the at least one connection line. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is described in greater detail below on the basis of embodiments and of the drawings in which: FIG. 1 shows a top view of a pressure measuring device according to the present invention in a partially cutaway view; FIG. 2 shows a side view of the pressure measuring device according to the present invention from FIG. 1; FIG. 3 shows a perspective view of the pressure measuring device according to the present invention from FIG. 1; and FIG. 4 shows a front view of the pressure measuring device according to the present invention from FIG. 1. DETAILED DESCRIPTION The pressure measuring device according to the present invention comprises a pressure gauge, which may be configured as a pressure sensor or pressure transmitter and comprises a pressure measuring member, such as a diaphragm. This can be arranged in a pressure gauge housing. The pressure gauge is connected via a connection line to a measured media source, i.e., in particular to a fluid source, which can be defined by both a line through which the fluid flows and a conta