CN107083769B - Negative pressure calibration device and method for vibrating wire type pore water pressure gauge - Google Patents
Negative pressure calibration device and method for vibrating wire type pore water pressure gauge Download PDFInfo
- Publication number
- CN107083769B CN107083769B CN201710486332.9A CN201710486332A CN107083769B CN 107083769 B CN107083769 B CN 107083769B CN 201710486332 A CN201710486332 A CN 201710486332A CN 107083769 B CN107083769 B CN 107083769B
- Authority
- CN
- China
- Prior art keywords
- vacuum pressure
- pressure gauge
- water
- calibration
- sealing
- Prior art date
- Legal status (The legal status 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 status listed.)
- Active
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Soil Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention discloses a negative pressure calibration device of a vibrating wire type pore water pressure gauge, which comprises a multi-stage vacuum pressure generating device, a calibration sealing tank, a frequency tester and a computer system, wherein the frequency tester is connected with the computer system; the multi-stage vacuum pressure generating device is connected with the calibration sealing tank, and a vacuum pressure gauge is arranged on the calibration sealing tank; and when the rate is timed, the vibrating wire type pore water pressure gauge is suspended in the calibration sealing tank through a pore pressure gauge cable, the pore pressure gauge cable is connected with a frequency tester, and the frequency tester is connected with a computer system. The invention obtains high-speed water flow by using the submersible pump, generates stable vacuum value by using the ejector, realizes the gradual loading and unloading of vacuum pressure by controlling the flow of the high-speed water flow, better accords with the actual working conditions of the pore water pressure gauge, can carry out more accurate negative pressure calibration on the vibrating wire type pore water pressure gauge so as to ensure the negative pressure measurement precision of the pore water pressure gauge, and has the advantages of time saving, labor saving, high efficiency and low cost.
Description
Technical Field
The invention relates to a testing device for monitoring the pore water pressure of a foundation, in particular to a negative pressure calibration device and method of a vibrating wire pore water pressure meter.
Background
In order to evaluate the foundation consolidation effect during the foundation treatment, the pore water pressure of each soil layer is generally monitored as an important parameter. The pore water pressure is obtained by embedding a pore water pressure meter into a corresponding soil layer, measuring related data and then calculating. At present, in practical engineering application, a vibrating wire type pore water pressure gauge is mostly adopted, and the pore water pressure is obtained through measuring the frequency conversion of a vibrating wire. However, when a negative pore water pressure value needs to be measured, the change of the vibrating wire deformation direction causes the change of the pore water pressure and the vibrating wire frequency conversion coefficient, and if the calculation is still performed according to the original conversion coefficient at the moment, the accuracy of the measured value of the pore water pressure is seriously influenced.
In order to accurately measure the pore water pressure value, the pore water pressure gauge must be calibrated before burying, and the relationship between the vibrating wire frequency and the actual pore water pressure is established through the calibration. The existing pore water pressure gauge calibration device mainly calibrates positive pore water pressure. The negative pore water pressure rate is mostly rated by adopting a mode of reversely applying positive pressure, so that time and labor are wasted, and the precision is difficult to guarantee.
Disclosure of Invention
The invention provides a negative pressure calibration device and method for a vibrating wire type pore water pressure gauge, aiming at solving the technical problems in the prior art.
The invention adopts a technical scheme for solving the technical problems in the prior art, which is as follows: a negative pressure calibration device of a vibrating wire type pore water pressure gauge comprises a multi-stage vacuum pressure generating device, a calibration sealing tank, a frequency tester and a computer system; the multistage vacuum pressure generating device is connected with the calibration sealing tank, and a vacuum pressure gauge is installed on the calibration sealing tank; the multistage vacuum pressure generating device comprises a submersible pump, a water tank, a water supply pipe, a flow dividing water pipe, a water return pipe, an ejector and an exhaust pipe; the submersible pump is installed in the water tank and controlled by the computer system, the submersible pump is connected with the water supply pipe, the water supply pipe is connected with the ejector, the ejector is connected with the calibration seal tank through the exhaust pipe, the ejector is connected with the water tank through the return pipe, the water supply pipe is provided with a flow control water valve and a diversion water pipe, the diversion water pipe is positioned at the downstream of the flow control water valve, the diversion water pipe is provided with a diversion flow control water valve, and the diversion water pipe is connected with the water tank; and the computer system performs fitting analysis on the frequency value measured by the frequency tester and the vacuum pressure value measured by the vacuum pressure gauge under the corresponding frequency, and calculates to obtain a negative pressure calibration coefficient.
A thermometer is arranged on the calibration sealing tank.
And a one-way valve is arranged in the air suction port of the ejector.
The calibration seal pot comprises a calibration seal pot body and a calibration seal cover, wherein a flange plate is welded at the top of the calibration seal pot body, the flange plate is fixedly connected with the calibration seal cover, a seal ring is arranged between the flange plate and the calibration seal cover, a pore pressure gauge cable is fixed on the calibration seal cover through a cable seal bolt, a vacuum pressure gauge is fixed on the calibration seal cover through a vacuum pressure gauge seal bolt, and a thermometer is fixed on the calibration seal cover through a thermometer seal bolt.
The invention adopts another technical scheme for solving the technical problems in the prior art, which is as follows: a method for calibrating the negative pressure of a vibrating wire type pore water pressure gauge by adopting the negative pressure calibration device comprises the following steps: 1) firstly, checking the states of a vacuum pressure meter and a frequency tester to ensure that the vacuum pressure meter and the frequency tester are in a calibration state, checking the water depth in a water tank and ensuring that a submersible pump is completely submerged underwater; suspending the vibrating wire type pore water pressure gauge in a calibration sealing tank through a pore pressure gauge cable; 2) automatically controlling and starting the submersible pump by using a computer system, performing vacuum test, and checking and calibrating the sealing performance of the sealed tank and the stability of vacuum pressure values at all levels; 3) after the trial pumping and the inspection are finished, the vacuum pressure of the calibration sealing tank is applied step by step, the vacuum pressure of each stage is roughly adjusted through the flow control water valve, and then the vacuum pressure is accurately adjusted through the flow diversion flow control water valve to accurately reach the required vacuum pressure value of each stage; in the process of applying the vacuum pressure, when the vacuum pressure of each stage is stable, reading the reading of the vacuum pressure gauge to obtain a vacuum pressure value, measuring the frequency value of the vibrating string type pore water pressure gauge by using a frequency tester, and automatically transmitting the frequency value to a computer system; in the operation process, the vacuum pressure of each stage is increased step by step, and the vacuum pressure is adjusted back after the stage is not increased; 4) after the vacuum pressure is applied to the last stage, the vacuum pressure is gradually released by adjusting the flow control water valve and the flow dividing flow control water valve, and in the vacuum pressure releasing process, when the vacuum pressure of each stage is stable, the vacuum pressure value and the frequency value of the vibrating string type pore water pressure gauge are obtained by adopting the method same as the method in the step 3); 5) and according to the frequency value measured by the frequency tester and the vacuum pressure value measured by the vacuum pressure gauge under the corresponding frequency, the computer system performs data fitting analysis on the two data, and calculates to obtain a negative pressure rate coefficient.
The invention has the advantages and positive effects that: the high-speed water flow is obtained by the submersible pump, the ejector is used for generating a stable vacuum value, and the vacuum pressure is gradually loaded and unloaded by controlling the flow rate of the high-speed water flow. And then, the relationship between the vacuum pressure and the vibrating wire frequency of each level is established by reading the vibrating wire frequency of the pore water pressure gauge corresponding to the vacuum pressure of each level, and the calibration coefficient is further obtained, so that the aim of accurately measuring the negative pore water pressure by adopting the vibrating wire type pore water pressure gauge is fulfilled. Compared with the existing negative pressure calibration technology of the pore water pressure gauge, the invention applies all levels of vacuum pressure values through the multi-stage vacuum pressure generating device, better accords with the actual working conditions of the pore water pressure gauge, and is convenient to ensure the precision of the pore water pressure gauge. Compared with the prior art, the flow dividing water pipe is arranged on the multistage vacuum pressure generating device, so that the vacuum pressure values at all levels are more reasonable and stable, and the flow dividing water pipe plays a role in finely adjusting and stabilizing the vacuum pressures at all levels. The negative pressure calibration device has simple structure, easy operation and low cost; in the actual operation process, the automatic control and the subsequent data processing of the negative pressure calibration process are easily realized through the control of a computer system, so that the negative pressure calibration efficiency of the vibrating wire type pore water pressure gauge is greatly improved.
Drawings
FIG. 1 is a schematic structural diagram of a negative pressure calibration device of a vibrating wire pore water pressure gauge according to the present invention;
FIG. 2 is a top view of a calibration sealing cap in the negative pressure calibration apparatus of the vibrating wire type pore water pressure gauge of the present invention;
FIG. 3 is a cross-sectional view of a-a of FIG. 2;
FIG. 4 is a top view of a tank body of a calibration seal tank in the vibrating wire type pore water pressure gauge negative pressure calibration device of the present invention;
fig. 5 is a sectional view taken along line b-b in fig. 4.
In the figure: 1. the device comprises a water tank, 2, a submersible pump, 3, a water supply pipe, 4, a flow control water valve, 5, a flow dividing water pipe, 6, a flow dividing flow control water valve, 7, an ejector, 8, a water return pipe, 9, an exhaust pipe, 10, a flow dividing sealing tank body, 11, a flow dividing sealing cover, 12, a sealing tank sealing fixing bolt, 13, a sealing groove, 14, a vacuum pressure gauge, 15, a vacuum pressure gauge sealing bolt, 16, a thermometer, 17, a thermometer sealing bolt, 18, a vibrating string type pore water pressure gauge, 19, a pore pressure gauge cable, 20, a cable sealing bolt, 21, a frequency tester, 22 and a computer system.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:
referring to fig. 1 to 5, a negative pressure calibration device of a vibrating wire pore water pressure gauge includes a multi-stage vacuum pressure generating device, a calibration sealed tank, a frequency tester 21 and a computer system 22.
The multistage vacuum pressure generating device is connected with the calibration sealing tank, a vacuum pressure gauge 14 is installed on the calibration sealing tank, and the vacuum pressure gauge 14 is a high-precision vacuum pressure gauge with higher precision.
The multistage vacuum pressure generating device comprises a submersible pump 2, a water tank 1, a water supply pipe 3, a flow dividing water pipe 5, a water return pipe 8, an ejector 7 and an exhaust pipe 9; immersible pump 2 is installed in the water tank 1, immersible pump 2 by computer system 22 control, immersible pump 2 with feed pipe 3 is connected, feed pipe 3 with ejector 7 is connected, ejector 7 passes through exhaust tube 9 with it connects to rate the seal pot, ejector 7 passes through wet return 8 with water tank 1 is connected be equipped with flow control water valve 4 and reposition of redundant personnel water pipe 5 on the feed pipe 3, reposition of redundant personnel water pipe 5 is located the low reaches of flow control water valve 4 be equipped with reposition of redundant personnel flow control water valve 6 on the reposition of redundant personnel water pipe 4, reposition of redundant personnel water pipe 5 with water tank 1 is connected.
And when the rate is timed, the vibrating wire type pore water pressure gauge 18 is suspended in the calibration sealed tank through a pore pressure gauge cable 19, the pore pressure gauge cable 19 is connected with the frequency tester 21, the frequency tester 21 is connected with the computer system 22, and the computer system 22 performs fitting analysis on the frequency value measured by the frequency tester 21 and the vacuum pressure value under the corresponding frequency measured by the vacuum pressure gauge 14 to calculate a negative pressure calibration coefficient.
In the present embodiment, in order to know the temperature state of the rate timing, a thermometer 16 is provided on the rate-setting airtight container, and a precision thermometer is preferably used as the thermometer 16. The sealed jar of calibration is including the sealed jar of the calibration jar body 10 of calibration and the sealed lid 11 of calibration the top welding of the sealed jar of the calibration jar body 10 has the ring flange, the ring flange with the sealed lid 11 of calibration adopts sealed jar sealed fixing bolt 12 fixed connection together, is equipped with the sealing ring between the ring flange with be equipped with seal groove 13 on the sealed lid 11 of calibration, seal groove 13 is located sealed jar sealed fixing bolt 12 inboardly, installs in seal groove 13 the sealing ring. The hole pressure gauge cable 19 is fixed on the calibration sealing cover 11 through a cable sealing bolt 20, the vacuum pressure gauge 15 is fixed on the calibration sealing cover 11 through a vacuum pressure gauge sealing bolt 15, and the thermometer 16 is fixed on the calibration sealing cover 11 through a thermometer sealing bolt 17. The water inlet of the ejector 7 is connected with the water supply pipe 3, the water outlet is connected with the water return pipe 8, and the air suction port is connected with the air exhaust pipe 9 to form a T-shaped structure. A check valve is arranged in an air suction port of the ejector 7 to prevent water flow from reversely flowing into the calibration seal tank through the air suction port.
The method for calibrating the negative pressure of the vibrating wire type pore water pressure gauge 18 by adopting the negative pressure calibration device comprises the following steps:
1) firstly, checking the states of the vacuum pressure gauge 14 and the frequency tester 21 to ensure that the vacuum pressure gauge and the frequency tester are in a calibration state, checking the water depth in the water tank 1, and ensuring that the submersible pump 2 is completely submerged under water; the vibrating wire type pore water pressure 18 meter is suspended in the calibration sealed tank through a pore pressure meter cable 19.
2) The submersible pump 2 is automatically controlled and started by the computer system 22, and the sealing performance of the sealed tank and the stability of vacuum pressure values of all stages are checked and calibrated.
3) After the trial pumping and the inspection are finished, the vacuum pressure is applied to the calibration sealing tank step by step, the vacuum pressure of each stage is roughly adjusted through the flow control water valve 4, and then the vacuum pressure is accurately adjusted through the shunt flow control water valve 6 to accurately reach the required vacuum pressure value of each stage; in the process of applying the vacuum pressure, when the vacuum pressure of each stage is stable, reading the reading of the vacuum pressure gauge 14 to obtain a vacuum pressure value, measuring the frequency value of the vibrating wire type pore water pressure gauge 18 by using the frequency tester 21, and automatically transmitting the frequency value to the computer system 22; in the operation process, the vacuum pressure of each stage is increased step by step, and the vacuum pressure is adjusted back after the stage is not increased.
4) After the vacuum pressure is applied to the last stage, the vacuum pressure is gradually released by adjusting the flow control water valve 4 and the flow diversion control water valve 6, and in the vacuum pressure releasing process, when the vacuum pressure of each stage is stable, the vacuum pressure value and the frequency value of the vibrating string type pore water pressure gauge 18 are obtained by adopting the method same as the method in the step 3).
5) According to the frequency value measured by the frequency tester 21 and the vacuum pressure value at the corresponding frequency measured by the vacuum pressure gauge 14, the computer system 22 performs data fitting analysis on the two data, and calculates to obtain a negative pressure rate coefficient.
The vacuum value range formed by the multi-stage vacuum pressure generating device adopted by the negative pressure calibration device is-99 kPa-0kPa, the pressure stabilizing value range of each stage of vacuum pressure is +/-1 kPa of theoretical grading vacuum pressure, and the vibrating wire type pore water pressure gauge with the negative pressure measuring range of-98 kPa-0kPa can be calibrated.
Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims (5)
1. A negative pressure calibration device of a vibrating wire type pore water pressure gauge is characterized by comprising a multi-stage vacuum pressure generating device, a calibration sealing tank, a frequency tester and a computer system;
the multistage vacuum pressure generating device is connected with the calibration sealing tank, and a vacuum pressure gauge is installed on the calibration sealing tank; the multistage vacuum pressure generating device comprises a submersible pump, a water tank, a water supply pipe, a flow dividing water pipe, a water return pipe, an ejector and an exhaust pipe; the submersible pump is installed in the water tank and controlled by the computer system, the submersible pump is connected with the water supply pipe, the water supply pipe is connected with the ejector, the ejector is connected with the calibration seal tank through the exhaust pipe, the ejector is connected with the water tank through the return pipe, the water supply pipe is provided with a flow control water valve and a diversion water pipe, the diversion water pipe is positioned at the downstream of the flow control water valve, the diversion water pipe is provided with a diversion flow control water valve, and the diversion water pipe is connected with the water tank;
and the computer system performs fitting analysis on the frequency value measured by the frequency tester and the vacuum pressure value measured by the vacuum pressure gauge under the corresponding frequency, and calculates to obtain a negative pressure calibration coefficient.
2. The vibrating wire type pore water pressure gauge negative pressure rating device according to claim 1, wherein a thermometer is arranged on the rating sealing tank.
3. The negative pressure calibration device of the vibrating wire pore water pressure gauge according to claim 1, wherein a one-way valve is provided in the suction port of the ejector.
4. The negative pressure rating device of the vibrating wire pore water pressure gauge according to claim 2, wherein the rating sealing tank comprises a rating sealing tank body and a rating sealing cover, a flange is welded on the top of the rating sealing tank body and fixedly connected with the rating sealing cover, a sealing ring is arranged between the flange and the rating sealing cover, the pore pressure gauge cable is fixed on the rating sealing cover through a cable sealing bolt, the vacuum pressure gauge is fixed on the rating sealing cover through a vacuum pressure gauge sealing bolt, and the thermometer is fixed on the rating sealing cover through a thermometer sealing bolt.
5. A method for calibrating the negative pressure of a vibrating wire pore water pressure gauge by using the negative pressure calibration device as claimed in claim 1, characterized by comprising the following steps:
1) firstly, checking the states of a vacuum pressure meter and a frequency tester to ensure that the vacuum pressure meter and the frequency tester are in a calibration state, checking the water depth in a water tank and ensuring that a submersible pump is completely submerged underwater; suspending the vibrating wire type pore water pressure gauge in a calibration sealing tank through a pore pressure gauge cable;
2) automatically controlling and starting the submersible pump by using a computer system, performing vacuum test, and checking and calibrating the sealing performance of the sealed tank and the stability of vacuum pressure values at all levels;
3) after the trial pumping and the inspection are finished, the vacuum pressure of the calibration sealing tank is applied step by step, the vacuum pressure of each stage is roughly adjusted through the flow control water valve, and then the vacuum pressure is accurately adjusted through the flow diversion flow control water valve to accurately reach the required vacuum pressure value of each stage; in the process of applying the vacuum pressure, when the vacuum pressure of each stage is stable, reading the reading of the vacuum pressure gauge to obtain a vacuum pressure value, measuring the frequency value of the vibrating string type pore water pressure gauge by using a frequency tester, and automatically transmitting the frequency value to a computer system; in the operation process, the vacuum pressure of each stage is increased step by step, and the vacuum pressure is adjusted back after the stage is not increased;
4) after the vacuum pressure is applied to the last stage, the vacuum pressure is gradually released by adjusting the flow control water valve and the flow dividing flow control water valve, and in the vacuum pressure releasing process, when the vacuum pressure of each stage is stable, the vacuum pressure value and the frequency value of the vibrating string type pore water pressure gauge are obtained by adopting the method same as the method in the step 3);
5) and according to the frequency value measured by the frequency tester and the vacuum pressure value measured by the vacuum pressure gauge under the corresponding frequency, the computer system performs data fitting analysis on the two data, and calculates to obtain a negative pressure rate coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710486332.9A CN107083769B (en) | 2017-06-23 | 2017-06-23 | Negative pressure calibration device and method for vibrating wire type pore water pressure gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710486332.9A CN107083769B (en) | 2017-06-23 | 2017-06-23 | Negative pressure calibration device and method for vibrating wire type pore water pressure gauge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107083769A CN107083769A (en) | 2017-08-22 |
| CN107083769B true CN107083769B (en) | 2022-06-21 |
Family
ID=59605888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710486332.9A Active CN107083769B (en) | 2017-06-23 | 2017-06-23 | Negative pressure calibration device and method for vibrating wire type pore water pressure gauge |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107083769B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112859945B (en) * | 2021-01-15 | 2022-06-17 | 四川大学 | Calibration platform pore pressure control system and control method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101358449B (en) * | 2008-09-11 | 2010-09-01 | 中国科学院武汉岩土力学研究所 | Pore water pressure measuring device in foundation stabilization zone |
| CN203642910U (en) * | 2013-12-02 | 2014-06-11 | 河海大学 | Dual-pore water pressure gauge-based settlement measurement device and system |
| CN103938606A (en) * | 2014-04-30 | 2014-07-23 | 中交天津港湾工程研究院有限公司 | Vibration wire type pore water pressure measuring head device capable of working stably in vacuum state in long term |
| CN106245690B (en) * | 2016-08-08 | 2019-01-08 | 浙江绩丰岩土技术股份有限公司 | Round-the-clock all the period of time foundation pit automatic monitoring early warning system and its monitoring and pre-alarming method |
-
2017
- 2017-06-23 CN CN201710486332.9A patent/CN107083769B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107083769A (en) | 2017-08-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106968934B (en) | Pump cavitation surplus Auto-Test System and its method | |
| CN106525358B (en) | Valve pressure testing system and method | |
| CN109029619B (en) | Volume measuring device based on dynamic differential pressure attenuation | |
| CN105806766A (en) | Flexible wall permeameter capable of measuring volume changes | |
| CN111729612B (en) | Piston pressure adjusting device and gas distribution method for intermediate gas concentration of high-temperature high-pressure kettle | |
| JP6471703B2 (en) | Airtight leak inspection device and airtight leak inspection method | |
| CN107083769B (en) | Negative pressure calibration device and method for vibrating wire type pore water pressure gauge | |
| CN102590016A (en) | Soil moisture characteristic curve measurement device and measurement method thereof | |
| CN108414345A (en) | A kind of erosion experiment bend pipe of configuration cathode protection device | |
| WO2017181444A1 (en) | Method and device for measuring diffusion coefficient of carbon dioxide in crude oil | |
| CN107747548B (en) | Semi-submersible type hydraulic testing device of vertical axial suction centrifugal pump | |
| CN103604573A (en) | Vacuum container sectional pressure raising quantitative leakage rate test method | |
| CN107328452B (en) | Device for measuring volume of irregular sealed cavity and operation method thereof | |
| CN210037114U (en) | Measuring system for measuring sealing performance of sealing box by oxygen-containing method | |
| CN116296054A (en) | Soil pressure sensor's mark system based on soil medium | |
| CN106698571B (en) | Full-automatic preparation and store device of airless water | |
| CN108956409A (en) | A kind of minute-pressure permeameter and test method | |
| CN209783837U (en) | multi-medium leakage rate adjustable leakage rate calibration system | |
| CN110005603B (en) | Device and method for testing air exhaust performance of micro vacuum pump | |
| CN210051489U (en) | Nuclear power station valve pressure test leak detection device | |
| CN206873431U (en) | A kind of type vibration wire pore pressure gauge negative pressure calibration device | |
| CN210089813U (en) | Simple and easy calibrating device of vapour-pressure type level gauge | |
| CN203083666U (en) | Water meter verification device | |
| CN108019344B (en) | Method for testing efficiency of electric water supply pump set | |
| CN209992349U (en) | Device for detecting permeability of sand-free concrete well pipe |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |