CN209858136U - Vacuum measuring device - Google Patents
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- CN209858136U CN209858136U CN201920807898.1U CN201920807898U CN209858136U CN 209858136 U CN209858136 U CN 209858136U CN 201920807898 U CN201920807898 U CN 201920807898U CN 209858136 U CN209858136 U CN 209858136U
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Abstract
The utility model discloses a vacuum measuring device, include: the vacuum cavity is internally provided with a weighing sensor; the mounting cavity is fastened at the top of the vacuum cavity and internally provided with a piston assembly; a coupling assembly; and the fastening is at the piston cylinder gland at installation cavity top, and the piston cylinder gland seals for a piston cylinder of piston assembly to the top of the piston in the piston cylinder gland forms the vacuum and measures the chamber, wherein: the installation cavity and a piston cylinder of the piston assembly are respectively provided with a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston and the piston cylinder. The vacuum measuring device of the utility model can balance the weight of the piston rod and the like, and measure the vacuum value from 0 pressure; the measurement range of a conventional gas piston manometer is extended down by 4 to 5 orders of magnitude.
Description
Technical Field
The utility model relates to a measure the field, especially relate to a vacuum measurement device.
Background
Vacuum is an important parameter in the fields of semiconductors, aerospace, pharmacy and the like, the measurement level of the vacuum is directly related to the scientific and technological level of the country, and certain products are even limited to export by developed countries. Therefore, increasing the vacuum metering level is critical to the high technology of a country.
In the prior art vacuum measurement, a gas piston type pressure gauge is adopted to accurately measure the gas pressure value (about 100kPa) of a small container in an expansion device, and then the small container in the expansion device is expanded to a large container through a series of small containers, so that 1 x 10 is generated in the final large volume-4Vacuum of Pa magnitude, if the measuring range of the gas piston type pressure gauge can extend downwards by 3 to 4 magnitudes, namely the measuring range of the piston type pressure gauge is 1Pa to 100Pa, the measuring range of the expansion device can be detected downwards to 1 x 10-7Pa。
Therefore, the measuring range of the gas piston type pressure gauge is extended downwards, the gas piston type vacuum measuring device with the measuring range of less than 100Pa is designed, the measuring range of the vacuum expansion device can be extended downwards greatly, and the problem of calibration of a vacuum gauge with the measuring range of (0.001-40) kPa can be solved.
SUMMERY OF THE UTILITY MODEL
The technical problem to be solved by the utility model is to provide a vacuum measuring device, which can balance the weight of a piston rod and the like, and measure the vacuum value from 0 pressure; the measurement range of a conventional gas piston manometer is extended down by 4 to 5 orders of magnitude.
In order to solve the technical problem, an embodiment of the utility model provides a vacuum measuring device, include: the vacuum cavity is internally provided with a weighing sensor; the mounting cavity is fastened at the top of the vacuum cavity and internally provided with a piston assembly; the coupling assemblies are respectively and fixedly connected between one piston of the piston assembly and the weighing sensor; the piston cylinder gland is fastened at the top of the mounting cavity and is sealed relative to a piston cylinder of the piston assembly, and a vacuum measuring cavity is formed at the top of a piston in the piston cylinder gland; the central axis of vacuum cavity, weighing sensor's the central axis, the central axis of installation cavity, piston assembly's the central axis and the central axis of piston cylinder gland are coaxial, wherein: the installation cavity and a piston cylinder of the piston assembly are respectively provided with a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston and the piston cylinder.
Wherein, the lubricating gas leads to the structure and includes: at least one first groove arranged on the inner wall of the vacuum cavity; at least one second groove arranged on the inner wall of the piston cylinder; a plurality of radial holes for gas communication are arranged between the first groove and the second groove; and a lubricating gas inlet port for introducing lubricating gas and a lubricating gas outlet port for discharging lubricating gas, which are respectively communicated with the first groove, wherein: a lubricating gas source is introduced from the lubricating gas inlet, and the lubricating gas passes through the first groove, the radial hole and the second groove and is extracted from the lubricating gas outlet.
The vacuum cavity and the vacuum measuring cavity are connected through a first pipeline, and a vacuum valve is arranged in the first pipeline; the piston cylinder gland is provided with a second pipeline communicated with the vacuum measurement cavity, a vacuum measurement interface is arranged in the second pipeline, and a vacuum stop valve is connected to the vacuum measurement interface.
The bottom of the piston cylinder gland is provided with an annular groove for placing a sealing ring, and the annular groove is used for isolating the introduced lubricating gas from the vacuum measurement cavity.
And O-shaped ring grooves for placing sealing rings are respectively arranged between the mounting cavity and a vacuum cavity cover of the vacuum cavity and between the mounting cavity and the piston cylinder.
Wherein, the clearance between piston and the piston cylinder faying face is less than 0.5 um.
The piston cylinder is made of hard alloy materials, the coaxiality tolerance of the inner cylindrical surface and the outer cylindrical surface of the piston cylinder is not more than 0.01mm, the straightness of the inner cylindrical surface is not more than 0.2um, and the roughness is not more than 0.02 um; the piston is made of low-density and high-hardness ceramic materials, the straightness of the cylindrical surface of the piston is not more than 0.1um, and the roughness of the cylindrical surface of the piston is not more than 0.02 um.
The position of the piston cylinder relative to the mounting cavity can be finely adjusted, so that the inner cylindrical surface of the piston cylinder is coaxial with the central axis of the bearing plane of the weighing sensor.
The center of a weighing plane of the weighing sensor is provided with an opening, and the bottom of the opening is provided with a first positioning conical surface.
Wherein, the coupling subassembly includes: metal pole and steel ball, the one end of metal pole is established to the plane, and the other end of metal pole is equipped with the second location conical surface, wherein: steel balls are respectively arranged in the first positioning conical surface and the second positioning conical surface, one end of the metal rod, which is provided with a plane, is inserted into the opening and is propped against the steel balls in the first positioning conical surface, and the steel balls in the second positioning conical surface at the other end of the metal rod are propped against the piston.
The utility model provides a vacuum measuring device has following beneficial effect: a piston cylinder of the mounting cavity and the piston assembly is respectively provided with a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston and the piston cylinder, and lubricating gas is led in and out through the lubricating gas conducting structure so as to reduce the friction force between the joint surfaces of the piston and the piston cylinder; the weighing sensor is used for weighing a first weight of the piston and the coupling assembly, vacuumizing the vacuum cavity and the vacuum measurement cavity, weighing a thrust generated by the measured vacuum acting on the piston in the vacuum measurement cavity and a second weight of a downward resultant force of the weights of the piston and the coupling assembly by the weighing sensor, acquiring a vacuum value acting in the vacuum measurement cavity according to the stored area of the piston, the first weight and the second weight, balancing the weight of the piston rod and the like, and measuring the vacuum value from 0 pressure; the measurement range of a conventional gas piston manometer is extended down by 4 to 5 orders of magnitude.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is an external structural schematic diagram of a vacuum measurement apparatus according to an embodiment of the present invention.
Fig. 2 is a schematic top view of a vacuum measuring apparatus according to an embodiment of the present invention.
Fig. 3 is a schematic cross-sectional structure view of the vacuum measuring apparatus according to the embodiment of the present invention, as shown in fig. 2 in the Y-Y direction.
Fig. 4 is a schematic cross-sectional structure diagram of a lubricating gas conducting structure of a vacuum measuring apparatus according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Referring to fig. 1 to fig. 4, a first embodiment of the vacuum measuring apparatus of the present invention is shown.
The vacuum measuring apparatus in this embodiment includes: the vacuum chamber comprises a vacuum chamber body 1 and a weighing sensor 2 arranged in the vacuum chamber body 1; the mounting cavity 3 is fastened at the top of the vacuum cavity 1, and a piston assembly 4 is arranged in the mounting cavity 3; the coupling assemblies 5 are respectively fixedly connected between a piston 41 of the piston assembly 4 and the weighing sensor 2; the piston cylinder gland 6 is fastened at the top of the mounting cavity 3, the piston cylinder gland 6 is sealed relative to a piston cylinder 42 of the piston assembly 4, and a vacuum measurement cavity B is formed at the top of a piston 41 in the piston cylinder gland 6; the central axis of the vacuum cavity 3, the central axis of the weighing sensor 2, the central axis of the mounting cavity 3, the central axis of the piston assembly 4 and the central axis of the piston cylinder gland 6 are coaxial, and the coaxial central axis is O;
a piston cylinder 42 of the installation cavity 3 and the piston assembly 4 is respectively provided with a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston 41 and the piston cylinder 42, and lubricating gas is led in and out through the lubricating gas conducting structure so as to reduce the friction force between the joint surfaces of the piston 41 and the piston cylinder 42;
the weighing sensor 5 weighs a first weight of the piston 41 and the coupling component 5, the vacuum cavity 1 and the vacuum measurement cavity B are vacuumized, the weighing sensor 5 weighs a thrust generated by the measured vacuum acting on the piston 41 in the vacuum measurement cavity B and a second weight of a downward resultant force of the weight of the piston 41 and the coupling component 5, and a vacuum value in the vacuum measurement cavity B is obtained according to the stored area, the first weight and the second weight of the piston 41.
In specific implementation, the vacuum cavity 1 is a rectangular box body and is composed of a vacuum cavity body 11, a nitrile rubber sealing gasket 12 and a vacuum cavity cover 13, the vacuum cavity body 11 and the vacuum cavity cover 13 are made of nonmagnetic metal materials, in this embodiment, aluminum alloy materials are subjected to aging treatment, the nitrile rubber sealing gasket 12 is flatly laid on the vacuum cavity body 11, the vacuum cavity cover 13 is placed on the nitrile rubber sealing gasket 12, and the nitrile rubber sealing gasket 12 is tightly pressed between the vacuum cavity body 11 and the vacuum cavity cover 13 through hexagon socket head cap screws.
Further, a vacuum interface 111 and a sealed wire passing socket 112 for connecting with a vacuum pump are respectively arranged on one side of the vacuum cavity 1; the vacuum cavity 1 is made of nonmagnetic metal material. During implementation, the sealed wire passing socket 112 is used for leading an electric connection wire of the weighing sensor 2 installed in the vacuum cavity 1 out of the vacuum cavity 1 and connecting the electric connection wire with the micro-processing assembly 7, the vacuum interface 111 is used for connecting a composite molecular vacuum pump and vacuumizing the vacuum cavity 1, and a circular hole communicated with the installation cavity 3 is formed in the middle of the vacuum cavity cover 13.
Further, the vacuum chamber 1 and the vacuum measuring chamber B are connected through a first pipeline T, and a vacuum valve T1 is arranged in the first pipeline T.
The weighing sensor 2 is positioned in the vacuum cavity 1 and fixed on the bottom surface of the vacuum cavity body 11 by screws. Further, the center of the weighing top surface of the load cell 2 is provided with an opening 21, and the bottom of the opening 21 is provided with a first positioning conical surface 211 for assembling the steel ball 51 of the coupling component 5.
Preferably, the first positioning tapered surface 211 has an angle of 90 ° and is disposed at the bottom of the opening 21.
Preferably, the method further comprises the following steps: a bottom plate 8 arranged at the bottom of the vacuum cavity 1, wherein the bottom plate 8 is provided with a horizontal bubble 81 for leveling the bottom plate; leveling feet 82 which can be adjusted manually are respectively arranged at four corners of the bottom plate 8. In specific implementation, the bearing surface of the weighing sensor 2 is perpendicular to the gravity direction by adjusting four leveling feet 82 on the bottom plate 8, and then the horizontal bubble 81 on the bottom plate 8 is leveled. Thus, as long as the horizontal bubble 81 is displayed in a horizontal state, the bearing surface of the load cell 2 is also in a horizontal state.
During specific implementation, the bottom plate 8 is a rectangular plate made of a rigid material, an aluminum plate subjected to stabilizing treatment is generally selected, the thickness of the aluminum plate is generally larger than 8mm, four corners of the aluminum plate are respectively provided with a leveling foot 82 capable of being manually adjusted, and a leveling bubble 81 is arranged at the edge of the bottom plate 8, so that the level of the adjustable bottom plate 8 can be conveniently adjusted.
The level of the load bearing plane of the load cell 2 is associated with a level bubble 81 on the bottom plate 8, and the coupling mechanism 5 connecting the piston 4 and the load cell 2 is placed in the central position of the load bearing plane of the precision load cell.
The mounting chamber 3 is fastened to the top of the vacuum chamber 1. During specific implementation, the mounting cavity 3 and the piston cylinder gland 6 are revolving bodies, and the piston cylinder gland 6 of the mounting cavity 3 is made of nonmagnetic metal materials.
O-shaped ring grooves 31 for placing sealing rings are respectively arranged between the mounting cavity 3 and the vacuum cavity cover 13 of the vacuum cavity 1 and between the mounting cavity 3 and the piston cylinder 42. The O-shaped ring groove 31 is used for placing a sealed O-shaped ring, the inner cylindrical surface of the mounting cavity 3 is vertically supported on the piston cylinder 42, and the piston cylinder gland 6 is fastened on the mounting cavity 3 through hexagon socket head cap screws.
The piston cylinder gland 6 is provided with a second pipeline P communicated with the vacuum measurement cavity B, a vacuum measurement interface P1 is arranged in the second pipeline P, a vacuum stop valve P2 is connected to the vacuum measurement interface P1, and the vacuum can be measured by connecting the vacuum stop valve P2. Meanwhile, the bottom of the piston cylinder gland 6 is provided with an annular groove 61 for placing a sealing ring, so that the introduced lubricating gas is isolated from the vacuum measurement cavity B.
Preferably, the mounting cavity 3 is fixed on the top of the vacuum cavity 1 through fastening screws, and the relative position of the mounting cavity 3 and the vacuum cavity 1 can be finely adjusted in the front, back, left and right directions so as to adjust the coaxiality of the piston assembly 4 and the bearing plane center of the weighing sensor 2. That is, the top pressure guiding hole 61 of the piston cylinder gland 6 is used for communicating with the atmosphere, the piston assembly 4 is assembled in the mounting cavity 3, and the position of the piston cylinder 42 relative to the vacuum cavity 1 can be finely adjusted in a front-back, left-right mode, that is, the position of the piston cylinder 42 relative to the mounting cavity 3 can be finely adjusted, so that the inner cylindrical surface of the piston cylinder 42 and the central axis of the bearing plane of the weighing sensor 2 are coaxially adjusted.
The piston assembly 4 includes: a piston cylinder 42 and a piston 41, the piston cylinder 42 is fastened between the piston cylinder gland 6 and the mounting cavity 3, and the piston 41 is freely floating in the piston cylinder 42. The piston cylinder 42 is made of hard alloy materials, and the piston 41 is made of low-density and high-hardness ceramic materials. The coaxiality tolerance of the inner cylindrical surface and the outer cylindrical surface of the piston cylinder 42 is not more than 0.01mm, the straightness of the inner cylindrical surface is not more than 0.2um, the roughness is not more than 0.02um, the straightness of the cylindrical surface of the piston 41 is not more than 0.1um, the roughness is not more than 0.02um, the clearance between the piston 41 and the piston cylinder 42 is not more than 0.5um, the piston 41 is freely floated in the piston cylinder 42, the piston cylinder 42 is installed and pressed in the installation cavity 3, and the fit between the piston cylinder 42 and the installation cavity 3 is clearance fit and the fit clearance is extremely.
Preferably, the difference in atmospheric pressure between the upper and lower sides of the piston 41 forms a thin film of lubricating gas in the gap between the piston 41 and the cylinder 42 to reduce the friction between the joining surfaces of the piston 41 and the cylinder 42.
The lubricating gas film is realized by the following structure that a lubricating gas conducting structure for forming the lubricating gas film in the clearance between the piston 41 and the piston cylinder 42 is respectively arranged on the mounting cavity 3 and one piston cylinder 42 of the piston assembly 4, and the lubricating gas is led in and led out through the lubricating gas conducting structure so as to reduce the friction force between the joint surfaces of the piston 41 and the piston cylinder 42.
In specific implementation, the lubricating gas conducting structure comprises: at least one first groove 91 provided on the inner wall of the vacuum chamber 3; at least one second groove 92 provided on the inner wall of the piston cylinder 42; a plurality of radial holes 93 for gas communication are provided between the first groove 91 and the second groove 92; and a lubricating gas introduction port 94 for introducing a lubricating gas and a lubricating gas discharge port 95 for discharging the lubricating gas, which communicate with the first groove 91, respectively, wherein: a source of lubricating gas is introduced through the lubricating gas inlet 94 and is drawn through the lubricating gas outlet 95 after passing through the first groove 91, the radial hole 93 and the second groove 92, so that a viscous gas flow is maintained between the joining surfaces of the piston 41 and the piston cylinder 42 during the measurement of the vacuum value.
By the lubricating gas conducting structure, the joint surface of the piston 41 and the piston cylinder 42 is a super mirror surface with the roughness less than 0.02um, the friction force between the piston 41 and the piston cylinder 42 is extremely small relative to the downward force formed by the vacuum action on the upper end of the piston 41, the lubricating gas guided into the piston gap from the middle hole of the piston cylinder 42 flows to the upper end and the lower end of the piston gap, and is pumped out from the lubricating gas outlet 95 through the hole on the piston cylinder 42 before reaching the end surface, the lubricating gas forms a dynamic lubricating gas film in the gap between the nano-scale piston 41 and the piston cylinder 42 with the thickness of 0.5um, the friction between the joint surface of the piston 41 and the piston cylinder 42 is further reduced, and the friction force Fr between the piston 41 and the piston cylinder.
Further, the coupling assembly 5 includes: a metal rod 51 and a steel ball 52, wherein one end of the metal rod 51 is a plane, and the other end of the metal rod 52 is provided with a second positioning conical surface 511, wherein: steel balls 52 are respectively arranged in the first positioning conical surface 211 and the second positioning conical surface 511, one end of the metal rod 51 with a plane surface is inserted into the opening 21 and is pressed against the steel balls 52 in the first positioning conical surface 211, and the steel balls 52 in the second positioning conical surface 511 at the other end of the metal rod 51 are pressed against the piston 41 and float and are pressed against the piston 41 of the piston cylinder 42.
In specific implementation, the length of the metal rod 51 is not less than 50mm, the lower end of the metal rod 51 is a plane, and the angle of the upper end of the metal rod is 90 ° to the second positioning conical surface 511.
Further, the method also comprises the following steps: and the microprocessor component 7 is used for storing the area of the piston 41 and respectively reading and recording the first weight and the second weight, the microprocessor component 7 is arranged outside the vacuum cavity 1/the mounting cavity 3, and the microprocessor component 7 is connected with the weighing sensor 2.
The vacuum measuring device in this embodiment can balance the peeling function based on the weighing sensorThe weight of the piston rod, etc., the sensor measures the downward force generated by the vacuum acting on the piston, regardless of the weight of the piston rod, etc., so that the vacuum value can be measured from 0 force; the piston adopts a unique design, gas with the pressure of more than 40kPa is guided into a gap between the piston cylinder and the piston rod from the middle part of the piston cylinder, and the gas is guided out of the piston cylinder 42 through a plurality of holes on the piston cylinder 42 before reaching the upper end and the lower end of the gap between the piston cylinder 42 and the piston 41, so that viscous gas flow can be formed in the gap between the piston cylinder 42 and the piston 41, the sensitivity of the piston 41 in the piston cylinder 42 is improved, and the gas flow can be prevented from entering the vacuum cavity 1 at the lower end of the piston 41. Thus, the vacuum degree of the reference end can be kept at 10 by the composite molecular vacuum pump-5Pa. Thus, even if the vacuum in the vacuum measurement chamber B at the upper end of the piston 41 is reduced to 1Pa, the gas flow in the clearance between the piston 41 and the piston cylinder 42 is still viscous flow, and the piston 41 can still float freely in the piston cylinder 42, thereby extending the measurement range of the conventional gas piston manometer down by 4 to 5 orders of magnitude.
When the vacuum measuring device with the structure is implemented, the central axis of the vacuum cavity 3, the central axis of the weighing sensor 2, the central axis of the mounting cavity 3, the central axis of the piston assembly 4 and the central axis of the piston cylinder gland 6 are coaxial, the coaxial central axis is O, the piston 41 with the known area a floats freely in the piston cylinder 42, the lower end of the piston 41 is connected with the high-precision weighing sensor 2 through the coupling mechanism 5, the upper end of the mounting cavity 3 is provided with a vacuum measuring interface P1, the interface is connected with vacuum to be measured through a vacuum stop valve P2, and the range of the vacuum to be measured is generally as follows: (0.001 to 40) kPa.
When vacuum measurement is performed, firstly, a lubricating gas source of not less than 40kPa is connected to the lubricating gas inlet, the lubricating gas source is introduced from the lubricating gas inlet 94, and the lubricating gas is extracted from the lubricating gas outlet 95 after passing through the first groove 91, the radial hole 93 and the second groove 92, so that gas viscous flow is maintained in the piston gap. Then, the vacuum valve P2 of the measurement port P1 is closed, the vacuum valve T1 connecting the upper and lower chambers of the piston is opened, and the vacuum chamber 1 and the vacuum are connected by the composite molecular vacuum pump through the vacuum port 111The measuring cavity B is vacuumized until 10-4Above the order of magnitude.
The vacuum cavity 1 connects the vacuum measurement cavity B with the vacuum cavity 1 through a vacuum pipeline T and is communicated or cut off by a vacuum valve T1, a vacuum port 111 on the vacuum cavity 1 is connected with a composite molecular vacuum pump, and the cavities at the upper and lower ends of the piston rod 41 can be vacuumized by the composite molecular vacuum pump until 10-5Pa, the vacuum valve T1 connecting the upper and lower end chambers of the piston 41 can be closed, only the vacuum chamber 1 is vacuumized and maintained at 10 degrees-5Pa of reference vacuum. In order to maintain a viscous flow of gas in the piston gap between the piston 41 and the piston cylinder 42 during vacuum measurement, a gas source of not less than 40kPa is introduced into the piston gap and the gas flow is guided out of the piston gap before reaching the upper and lower ends of the piston gap, so that the piston is made sensitive by maintaining the viscous gas flow in the piston gap and the gas flow is prevented from entering the vacuum measurement chamber B at the upper end of the piston rod and the vacuum chamber 1 at the lower end of the piston rod, and the stability of the measurement environment is deteriorated.
Load cell 2 weighs a first weight f of piston 41 and coupling assembly 51：
f1＝Wtare
The vacuum valve T1 connecting the upper and lower cavities of the piston is closed, the vacuum stop valve P2 of the measuring port P1 is opened, and the measured vacuum enters the vacuum measuring cavity B. After stabilization, the microprocessor assembly 7 reads the downward thrust P × A generated on the piston by the vacuum to be measured and weighed by the precision weighing sensor 2 and the second weight f of the downward resultant force of the weight Wtare of the piston 41 and the coupling mechanism 52：
f2＝P×A+Wtare
The two above equations are subtracted:
f2-f1＝P×A
namely:
in the above formula, the area a of the piston 41 is a fixed value and can be measured in advance, so that the vacuum value can be calculated in real time and displayed simultaneously by the transmission of the weight values f2 and f1 measured by the load cell 2 to the microprocessor module 7 outside the vacuum chamber through the cable and the sealed wire passing socket.
Implement the utility model discloses a vacuum measuring device has following beneficial effect: a piston cylinder of the mounting cavity and the piston assembly is respectively provided with a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston and the piston cylinder, and lubricating gas is led in and out through the lubricating gas conducting structure so as to reduce the friction force between the joint surfaces of the piston and the piston cylinder; the weighing sensor is used for weighing a first weight of the piston and the coupling assembly, vacuumizing the vacuum cavity and the vacuum measurement cavity, weighing a thrust generated by the measured vacuum acting on the piston in the vacuum measurement cavity and a second weight of a downward resultant force of the weights of the piston and the coupling assembly by the weighing sensor, acquiring a vacuum value acting in the vacuum measurement cavity according to the stored area of the piston, the first weight and the second weight, balancing the weight of the piston rod and the like, and measuring the vacuum value from 0 pressure; the measurement range of a conventional gas piston manometer is extended down by 4 to 5 orders of magnitude.
Claims (10)
1. A vacuum measurement device, comprising:
the weighing sensor is arranged in the vacuum cavity;
the mounting cavity is fastened at the top of the vacuum cavity and internally provided with a piston assembly;
the coupling assemblies are respectively and fixedly connected between one piston of the piston assembly and the weighing sensor; and
the piston cylinder gland is fastened at the top of the mounting cavity and is sealed relative to a piston cylinder of the piston assembly, and a vacuum measuring cavity is formed at the top of the piston in the piston cylinder gland;
the central axis of vacuum cavity, the central axis of weighing sensor, the central axis of installation cavity, the central axis of piston subassembly and the central axis of piston cylinder gland are coaxial, wherein:
and a lubricating gas conducting structure for forming a lubricating gas film in a gap between the piston and the piston cylinder is respectively arranged on the mounting cavity and one piston cylinder of the piston assembly.
2. The vacuum measuring device of claim 1, wherein the lubricating-gas conducting structure comprises:
at least one first groove arranged on the inner wall of the vacuum cavity;
the at least one second groove is formed in the inner wall of the piston cylinder;
a plurality of radial holes for gas communication are arranged between the first groove and the second groove; and
a lubricating gas inlet port for introducing a lubricating gas and a lubricating gas outlet port for discharging the lubricating gas, which are respectively communicated with the first groove, wherein:
and a lubricating gas source is introduced from a lubricating gas inlet, and the lubricating gas passes through the first groove, the radial hole and the second groove and is extracted from the lubricating gas outlet.
3. The vacuum measuring device according to claim 1, wherein the vacuum chamber body and the vacuum measuring chamber are connected by a first pipeline, and a vacuum valve is arranged in the first pipeline;
and a second pipeline communicated with the vacuum measuring cavity is arranged on the piston cylinder gland, a vacuum measuring interface is arranged in the second pipeline, and a vacuum stop valve is connected to the vacuum measuring interface.
4. The vacuum measuring device of claim 2, wherein the bottom of the piston cylinder gland is provided with an annular groove for seating a seal ring to isolate the introduced lubricating gas from the vacuum measuring chamber.
5. The vacuum measuring device according to claim 2, wherein O-ring grooves for placing sealing rings are respectively provided between the mounting cavity and a vacuum cavity cover of the vacuum cavity and between the mounting cavity and the piston cylinder.
6. The vacuum measuring device of claim 1, wherein a clearance between the piston and the piston cylinder interface is less than 0.5 um.
7. The vacuum measuring device of claim 1, wherein the piston cylinder is made of cemented carbide, the coaxiality tolerance of the inner cylindrical surface and the outer cylindrical surface of the piston cylinder is not more than 0.01mm, the straightness of the inner cylindrical surface is not more than 0.2um, and the roughness is not more than 0.02 um;
the piston is made of low-density and high-hardness ceramic materials, the straightness of the cylindrical surface of the piston is not more than 0.1um, and the roughness of the cylindrical surface of the piston is not more than 0.02 um.
8. The vacuum measuring device of claim 1, wherein the position of the piston cylinder relative to the mounting cavity is fine-adjustable such that the inner cylindrical surface of the piston cylinder and the central axis of the load bearing plane of the load cell are coaxial.
9. The vacuum measuring device as claimed in claim 1, wherein the weighing plane of the weighing cell is centrally provided with an opening, and the bottom of the opening is provided with a first positioning cone.
10. The vacuum measurement device of claim 9, wherein the coupling assembly comprises: metal pole and steel ball, the one end of metal pole is established to the plane, the other end of metal pole is equipped with the second location conical surface, wherein:
the steel balls are respectively arranged in the first positioning conical surface and the second positioning conical surface, one end, with a plane, of the metal rod is inserted into the opening and pressed against the steel balls in the first positioning conical surface, and the steel balls in the second positioning conical surface at the other end of the metal rod are pressed against the piston.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920807898.1U CN209858136U (en) | 2019-05-31 | 2019-05-31 | Vacuum measuring device |
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| CN201920807898.1U CN209858136U (en) | 2019-05-31 | 2019-05-31 | Vacuum measuring device |
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| CN209858136U true CN209858136U (en) | 2019-12-27 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110174212A (en) * | 2019-05-31 | 2019-08-27 | 辽宁红沿河核电有限公司 | A kind of vacuum measuring device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110174212A (en) * | 2019-05-31 | 2019-08-27 | 辽宁红沿河核电有限公司 | A kind of vacuum measuring device |
| CN110174212B (en) * | 2019-05-31 | 2024-07-09 | 辽宁红沿河核电有限公司 | Vacuum measuring device |
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