KR102199987B1 - Hydraulic Deadweight Tester for High Pressure Gases - Google Patents

Abstract

The present invention provides a hydraulic weight-type pressure gauge for high-pressure gas, which improves manufacturability and facilitates injection of liquid by forming a gas-liquid separation space in a main column. According to the present invention, the hydraulic weight-type pressure gauge for high-pressure gas comprises: the main column installed vertically on a main body base and the gas-liquid separation space is formed therein; a central column which is inserted and installed inside the main column, has an outer surface spaced apart from an inner surface of the main column to form the gas-liquid separation space, and is filled with a liquid medium to form a hydraulic space where hydraulic pressure acts; a cylinder coupled to an upper part of the main column and installed in contact with an upper surface of the central column; a piston which is installed so as to be movable up and down inside the cylinder and pressurizes or depressurizes while moving up and down toward the hydraulic space of the central column; and a piston cap to which the top of the piston is fixed.

Description

Hydraulic Deadweight Tester for High Pressure Gases {Hydraulic Deadweight Tester for High Pressure Gases}

The present invention relates to a hydraulic deadweight pressure gauge for a high pressure gas, and more particularly, to a hydraulic deadweight pressure gauge for a high pressure gas that can utilize an existing piston-cylinder module and improves fabrication and makes it easy to inject a liquid. will be.

In general, industrial sites are widely used in piping systems for high-pressure gas, and there are many cases where other components (oil and other foreign matter) should not be mixed in the interior of the piping except for the components of the gas used.

For example, piping systems that use relatively high-pressure gases such as hydrogen charging stations for fuel cells, natural gas (CNG) charging stations, and other high-purity oxygen (O ₂ ) should always be isolated from materials that may cause fire. . Even if there is no actual heat source (flame, etc.), the high-pressure gas itself has a risk of expansion, and when contaminants such as oil are mixed with the high-pressure gas, heat is generated as the high-pressure gas compresses and expands. An explosive fire may occur.

In such a high-pressure gas piping system, a pressure gauge is installed to check the internal pressure, and regular inspection of these pressure gauges is required.

In addition, since the pressure gauge is used in a special environment, care should be taken not to be exposed to contamination even during regular inspection of the pressure gauge. In addition, there are cases where an experiment with very high precision is required when checking a pressure gauge. A pressure gauge that satisfies all these requirements is a deadweight pressure gauge.

The deadweight pressure gauge is known as the most reliable pressure gauge, although it is a simple mechanical device that well expresses the definition of pressure (P=F/A), "Pressure force per unit area (A) (㎡) (F) (N)".

The deadweight pressure gauge uses a method of measuring pressure using a force equilibrium state, and is a pressure gauge used as a primary standard (a calibration standard or a standard pressure generator) in hydraulic and pneumatic measurements.

Korean Patent Publication Nos. 10-1641081, 10-1091648, 10-0982284, 10-0806959, 10-0542229, 10-0449151, 10-0439160, and 10-0284161 No., Patent Publication Nos. 10-2011-0092776, 10-2017-0065194, and U.S. Patent Publication No. 6,701,791 disclose various technologies related to a deadweight pressure gauge.

The weight pressure gauge measures the pressure by using the equilibrium state between the piston and the mass of the weight placed on it and the pressure of the fluid applied to the cylinder, and the standard pressure (P _S ) of the weight pressure gauge is expressed by the following equation. Is defined.

In Equation 1, P _S represents the standard pressure (unit: Pa), ΣM represents the sum (unit: kg) of the mass of the weight loaded on the piston including the piston mass, and g represents the local gravitational acceleration (unit: :㎨), and A represents the reference cross-sectional area (unit: m2) of the piston-cylinder.

In a deadweight pressure gauge, when pressure is applied to a medium by means of a pressure generator, the piston is pushed and moved, and the force pushed by the medium (pressure) and the cross-sectional area of the piston-cylinder and the force that presses it (F=M*g) are balanced. And the pressure at this time is the standard pressure.

The compression medium for operation of the deadweight pressure gauge is divided into gas and liquid, and the liquid can be operated in the measuring range of 500 MPa to 1 GPa, but the gas is at the maximum level of 10 MPa (1,500 psi).

In the case of a deadweight pressure gauge using a gas medium, pistons and cylinders are made of precision-machined cylindrical metal or ceramic. Due to the nature of operation, gas easily escapes through the gap between the piston-cylinder compared to liquid (oil). Since the time is very short, the unique operation of the deadweight pressure gauge cannot be sufficiently exhibited. Therefore, the measurement range of a weight pressure gauge using purely a medium as a gas is limited to approximately 10 MPa.

To overcome this, a liquid (usually oil such as lubricating oil) is filled in a space with a certain volume using a gas compressed at high pressure, and the liquid is compressed with gas to operate a hydraulic deadweight pressure gauge. Using this method, it is possible to measure even the compression limit level of the gas, and up to 100 MPa to 140 MPa.

The simplest method is to use the incompressibility of the liquid. A device that can separate gas and liquid is installed between the gas part and the hydraulic part (hydraulic weight pressure gauge). It is a method of operating a deadweight pressure gauge by putting it in, pressurizing it, and pushing (compressing) this gas into a liquid.

For example, a gas-liquid separator is installed in the middle of a hydraulic weight pressure gauge and a gas part, and the gas is slowly pressurized so that the hydraulic weight pressure gauge operates at the point where the cross-sectional area of the piston and the size of the mass and force are balanced. Make up.

However, this method is simple and inexpensive, but it takes up a lot of space and is inconvenient to use, so it is not used much.

In addition, in this method, there is a high possibility that liquid (oil) is mixed with gas and discharged in the process of depressurizing after pressurization, which is likely to contaminate the interior of the equipment under test.

In U.S. Patent No. 6,701,791, a liquid container is installed on the side of the cylinder, and gas pressure equal to the pressure received from the bottom of the piston flows into the upper part of the liquid container, and the liquid is introduced through a small hole on the side of the cylinder. A piston-cylinder module configured to act like a pressure gauge is disclosed.

In the case of installing a liquid container in a conventional piston-cylinder module, there is a problem in that the structure is complicated, making it difficult to manufacture, there are many difficulties in injecting liquid, and the existing piston module cannot be utilized.

The present invention has been made in view of the above points, and provides a hydraulic weight pressure gauge for a high-pressure gas, which is easy to inject liquid and improves fabrication by forming a gas-liquid separation space in a main column.

The hydraulic deadweight pressure gauge for high-pressure gas according to an embodiment of the present invention is installed vertically on the main body base and has a gas-liquid separation space formed therein, and is inserted into the main column to form the gas-liquid separation space. The outer surface is spaced apart from the inner surface of the main column, and the inner surface is filled with a liquid medium to form a hydraulic space for hydraulic pressure, and the main column is installed in contact with the upper surface of the main column. It comprises a cylinder, a piston installed in the interior of the cylinder so as to be able to move upwardly and to pressurize or depressurize while moving toward the hydraulic space of the central column, and a piston cap to which the upper end of the piston is fixed.

It is also possible to install a piston guide member in the lower part of the cylinder, which is inserted into the central pillar and guides the upward movement of the piston.

In the central column, a plurality of hydraulic flow paths for flowing liquid (hydraulic pressure) by communicating the internal hydraulic space and the external gas-liquid separation space are formed in a radial direction.

The main column is connected to a pressurizing device so that the pressure of the high-pressure gas acts, and a central flow path formed in the center of the lower side so as not to directly communicate with the gas-liquid separation space, and a horizontally formed horizontally to communicate with the upper end of the central flow path And a flow path, a vertical flow path connected to one end of the horizontal flow path and formed vertically, and a connection flow path formed to connect the upper end of the vertical flow path and the gas-liquid separation space to each other.

The opposite end portion of the horizontal flow passage not connected to the vertical flow passage may be formed to penetrate to the outside, and the end portion exposed to the main column surface of the horizontal passage may be configured to connect a plug so as to be opened and closed as necessary. .

It is also possible to configure the upper end of the vertical flow path to penetrate the outside so as to be exposed to the upper surface of the main column, and to connect a plug so as to be opened and closed as necessary at the end of the vertical flow channel exposed to the upper surface of the main column. Do.

In the above, the plug of the horizontal flow channel and the vertical flow channel can be used as an injection hole for injecting a gas or liquid medium.

It is preferable to install an O-ring on the outer peripheral surface of the upper end of the central pillar to maintain airtightness between the inner surface of the main pillar.

According to the hydraulic weight pressure gauge for high pressure gas according to the embodiment of the present invention, since the gas-liquid separation space is formed in the main column, the processability and fabrication are greatly improved compared to forming the gas-liquid separation space on the piston-cylinder module side, and The cost is reduced.

In addition, according to the hydraulic deadweight pressure gauge for high pressure gas according to an embodiment of the present invention, since a gas-liquid separation space is formed in the main column, it is possible to utilize the existing piston-cylinder module, and it is possible to reduce the manufacturing cost. .

And, according to the hydraulic deadweight pressure gauge for high-pressure gas according to an embodiment of the present invention, since it is possible to inject a gas or liquid medium through a plug of a horizontal passage or a vertical passage of a main column installed vertically, injection of the medium This is done easily.

1 is a partial cross-sectional perspective view showing a hydraulic deadweight pressure gauge for high pressure gas according to an embodiment of the present invention.
2 is a partial cross-sectional perspective view showing a state in which a main column and a central column are assembled in the hydraulic deadweight pressure gauge for high pressure gas according to an embodiment of the present invention.
3 is a partial cross-sectional perspective view showing a state in which a main column and a central column are separated in a hydraulic deadweight pressure gauge for high pressure gas according to an embodiment of the present invention.
4 is a cross-sectional view showing a state in which the weight is not loaded in the hydraulic weight pressure gauge for high pressure gas according to an embodiment of the present invention.
5 is a cross-sectional view showing a state in which a weight is loaded in a hydraulic weight pressure gauge for a high pressure gas according to an embodiment of the present invention.

Next, a preferred embodiment of a hydraulic deadweight pressure gauge for high pressure gas according to the present invention will be described in detail with reference to the drawings.

The present invention can be implemented in various forms, and is not limited to the embodiments described below.

Hereinafter, in order to clearly describe the present invention, detailed descriptions of parts that are not closely related to the present invention are omitted, and the same or similar elements are denoted by the same reference numerals throughout the description of the present invention, and repetitive descriptions are omitted. .

First, the hydraulic deadweight pressure gauge for high-pressure gas according to an embodiment of the present invention, as shown in Figs. 1 to 3, the main column 10, the central column 30, the cylinder 50, and the piston It consists of (60) and, including a piston cover (70).

The main column 10 is installed perpendicular to the main body base (not shown in the drawing).

A gas-liquid separation space 18 is formed inside the main column 10.

The main column 10 is connected to a pressurizing device (not shown) so that the pressure of the high-pressure gas acts, and a central flow path 13 is formed in the center of the lower side so as not to directly communicate with the gas-liquid separation space 18 do.

The central flow path 13 is connected to a pressure generator (not shown in the drawing), and is configured such that a constant pressure set in the high-pressure gas acts.

A horizontal passage 15 is formed in the main column 10 so as to communicate with the upper end of the central passage 13.

In addition, a vertical flow path 17 is vertically formed in the main column 10 while being connected to one end of the horizontal flow path 15.

In addition, a connection passage 21 is formed in the main column 10 to connect the upper end of the vertical passage 17 and the gas-liquid separation space 18 to each other.

The opposite end of the horizontal passage 15 that is not connected to the vertical passage 17 is formed to penetrate to the outside.

The end portion exposed to the surface of the main column 10 of the horizontal flow path 15 is configured to couple the plug 16 so as to be opened and closed as necessary.

In addition, the upper end of the vertical flow path 14 is formed to penetrate the outside so as to be exposed toward the upper surface of the main column 10.

The end of the vertical flow path 14 exposed to the upper surface of the main column 10 is configured to couple the plug 17 so as to be opened and closed as necessary.

In the above, the plugs 16 and 17 of the horizontal passage 15 and the vertical passage 14 can be utilized as injection holes for injecting a gas or liquid medium.

The main body 12 of the main column 10 is formed in a cylindrical shape in which a gas-liquid separation space 18 with a bottom blocked therein is formed.

The central pillar 30 is inserted and installed in the main pillar 10.

The central pillar 30 is installed so that the gas-liquid separation space 18 is formed so that the outer surface thereof is spaced apart from the inner surface of the main column 10.

The inside of the central pillar 30 is filled with a liquid medium to form a hydraulic space 34 in which hydraulic pressure acts.

In the central column 30, a plurality of hydraulic passages 38 are formed in a radial direction by communicating the internal hydraulic space 34 and the external gas-liquid separation space 18 to each other to flow a liquid (hydraulic pressure).

It is preferable to install an O-ring 46 on the outer circumferential surface 35 of the upper end of the central column 30 in order to maintain airtightness between the inner surface of the main column 10 and the inner surface of the main column 10.

An O-ring groove 36 into which the O-ring 46 is inserted is formed on the outer peripheral surface 35 of the upper end of the central pillar 30.

An assembly groove 19 is formed inside the main pillar 10, and an assembly protrusion 39 inserted into the assembly groove 19 is formed at a lower end of the central pillar 30.

A female screw is formed in the assembly groove 19, and a male screw is formed in the assembly protrusion 39, and the central pillar 30 is integrally fixedly coupled to the main pillar 10 by screwing.

It is also possible to form a wrench groove 37 for rotating the central pillar 30 for screwing in the inside of the central pillar 30.

The main body 32 of the central pillar 30 is formed in a cylindrical shape in which a hydraulic space 34 with a floor blocked therein is formed.

The wrench groove 37 is formed on the inner bottom of the central pillar 30.

The cylinder 50 is coupled and installed on the upper portion of the main column 10.

It is also possible to form a female screw portion 24 on the inner surface of the upper end of the main column 10, and to assemble the lower end of the cylinder 50 by screwing.

A stepped step 22 is formed above the gas-liquid separation space 18 of the main column 10 so that the bottom surface of the cylinder 50 is in contact and the upper surface is closed.

The lower portion of the cylinder 50 is installed to be in contact with the upper surface of the central pillar 30.

The piston 60 is installed in the cylinder 50 so as to move upwardly.

The piston 60 is installed to pressurize or depressurize while moving upwardly toward the hydraulic space 34 of the central pillar 30.

The upper end of the piston 60 is fixed to the bottom surface of the piston cap 70.

The piston cap 70 is installed so as to be able to move up and down together with the piston 60.

The load of the weight acts on the piston cap 70.

In the above, the configuration of the cylinder 50, the piston 60, and the piston cap 70 can be implemented by applying various configurations of the existing piston cylinder module, so a detailed description will be omitted.

In addition, it is possible to install a piston guide member 56 that is inserted into the central column 30 and guides the upward movement of the piston 60 at the lower portion of the cylinder 50.

The piston guide member 56 may be formed integrally with the cylinder 50, or may be manufactured as a separate component from the cylinder 50 and configured to be assembled.

When the piston guide member 56 is formed and installed as described above, since the portion of the central column 30 into which the piston 60 is inserted does not need to be maintained with high precision, the manufacture of the central column 30 is facilitated.

Next, the operation of the hydraulic deadweight pressure gauge for a high pressure base according to the present invention configured as described above will be described with reference to FIGS. 4 and 5.

First, as shown in FIG. 4, in a state in which the weight of the weight does not act on the piston cap 70, the piston 60 and the piston cap 70 are moved upwards.

In the above state, the pressure of the high-pressure gas (indicated by soft point hatching in FIG. 4) flowing through the central flow path 13 is the liquid medium injected into the gas-liquid separation space 18 and the hydraulic space 34 (in FIG. The piston 60 is moved upwards by the pressure of the liquid medium by acting on (indicated by dark point hatching).

In the above, the high-pressure gas transfers pressure while moving to the gas-liquid separation space 18 through the central passage 13, the horizontal passage 15, the vertical passage 14, and the connection passage 21.

And, as shown in Figure 5, when the load of the weight acts on the piston cap 70, the piston cap 70 moves downward, the piston 60 also moves downward, and the piston ( According to the movement of 60), pressure increases and acts on the liquid medium (indicated by dark dot hatching in FIG. 5) in the hydraulic space 34, and the liquid medium in the organic liquid separation space 18 through the hydraulic flow path 38 High-pressure gas (indicated by soft point hatching in FIG. 5) is partially pushed out of the gas-liquid separation space 18 due to the electrolytic pressure, so that the connecting passage 21, the vertical passage 14, the horizontal passage 15, and the central passage 13 Through this, the pressure acts toward the pressure generator (not shown in the drawing), and the pressure of the high-pressure gas rises.

In the above, it is possible to calculate the standard pressure using the pressure change of the high-pressure gas and the mass of the weight and the piston.

In the above, a preferred embodiment of the hydraulic deadweight pressure gauge for high pressure gas according to the present invention has been described, but the present invention is not limited thereto, and various modifications are carried out within the scope of the claims, the description of the invention and the accompanying drawings. It is possible, and this also falls within the scope of the present invention.

10-main column, 12-main column body, 14-vertical passage, 15-horizontal passage
16,17-plug, 18-gas-liquid separation space, 19-assembly groove, 21-connection channel
22-stepped, 24-female thread, 30-central pillar, 32-central pillar body
35-Outer circumference of upper part, 36-O-ring groove, 37-Wrench groove, 38-Hydraulic flow path
39-assembly protrusion, 50-cylinder, 56-piston guide member, 60-piston
70-piston cap

Claims (7)

A main column installed vertically on the main body base and forming a gas-liquid separation space therein,
A central pillar that is inserted and installed inside the main pillar and has an outer surface spaced apart from the inner surface of the main pillar so that the gas-liquid separation space is formed, and is filled with a liquid medium to form a hydraulic space in which hydraulic pressure acts;
A cylinder coupled to the upper portion of the main pillar and installed in contact with the upper surface of the central pillar;
A piston installed in the cylinder so as to move upwardly and to pressurize or reduce pressure while moving toward the hydraulic space of the central column;
It includes a piston cap to which the upper end of the piston is fixed,
The main column is connected to a pressurizing device so that the pressure of the high-pressure gas acts, and a central flow path formed in the center of the lower side so as not to directly communicate with the gas-liquid separation space, and a horizontally formed horizontally to communicate with the upper end of the central flow path. A flow path, a vertical flow path connected to one end of the horizontal flow path and formed vertically, and a connection flow path formed to connect the upper end of the vertical flow path and the gas-liquid separation space,
For high-pressure gas, the opposite end of the horizontal flow path not connected to the vertical flow path is formed to penetrate to the outside, and the end exposed to the main column surface of the horizontal flow path is configured to connect a plug so that it can be opened or closed as needed. Hydraulic deadweight pressure gauge.
The method according to claim 1,
A hydraulic deadweight pressure gauge for high-pressure gas installed at a lower portion of the cylinder and provided with a piston guide member that is inserted into the central pillar and guides the vertical movement of the piston.
The method according to claim 1,
A hydraulic weight pressure gauge for high-pressure gas in which a plurality of hydraulic flow paths through which liquid flows by communicating the internal hydraulic space and the external gas-liquid separation space are formed in the radial direction in the central pillar.
delete delete The method according to claim 1,
For high-pressure gas configured to allow the upper end of the vertical flow path to be exposed to the outside so as to be exposed toward the upper surface of the main column, and to connect a plug to be opened and closed as necessary at the end of the vertical flow path exposed to the upper surface of the main column Hydraulic deadweight pressure gauge.
The method according to claim 1,
A hydraulic deadweight pressure gauge for high-pressure gas, wherein an O-ring is installed on the outer peripheral surface of the upper end of the central column to maintain airtightness between the inner surface of the main column.

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