Testing device and method for gas viscosity under multiple working conditions

Abstract

The present invention relates to the technical field of gas viscosity testing, and is a testing device and method for gas viscosity under multiple working conditions, the former comprising a constant temperature box, a capillary, a driving mechanism, and a first cylinder and a second cylinder having the same structure and arranged in opposite directions. The structure of the present invention is reasonable and compact. The present application adopts coaxial equal-diameter double cylinders installed in opposite directions, which can solve two problems in the capillary method test of gas viscosity: one is the adjustment of the gas state, using the driving mechanism to realize the left and right movement of the piston rod, thereby changing the volume of the rodless chamber of the cylinder, so that the driving mechanism and the cylinder can be used to realize the pressurization or decompression function, so that the gas reaches the set pressure; the second is to maintain the constant gas state during the test. During the test, the first cylinder, the second cylinder and the capillary are connected to form a closed test loop. Changing the piston movement speed of the two cylinders can also adjust the gas flow in the test loop to meet the needs of performing multiple groups of tests under the same gas state.

Description

Technical Field

[0001] The invention relates to the technical field of gas viscosity testing, in particular to a device and method for testing gas viscosity under multiple working conditions. Background Art

[0002] The accurate measurement of gas viscosity is of great significance in many key areas, including petrochemicals, transportation, and the defense industry. Gas viscosity is closely related to its state, such as high-pressure natural gas in oil and gas wells and negative-pressure air in high-altitude environments. There are two main methods for obtaining gas viscosity: one is the theoretical calculation method, which estimates based on molecular kinetic theory and the equation of state. Although this method is simple, it is limited by the assumptions of the theoretical model and cannot accurately reflect the true viscosity of the gas under actual working conditions. In particular, the error is large in high-temperature, high-pressure, or non-ideal gas systems. The other is the experimental measurement method, which includes the falling ball method, the vibrating wire method, and the capillary method. The falling ball method is limited to transparent media and has high requirements for detecting the ball's motion. The vibration method requires isolation from external vibration interference and has a complex device structure. The capillary method is widely used for gas viscosity testing in laboratories and industrial sites due to its simple structure and wide range of applications.

[0003] The principle of measuring gas viscosity using the capillary method is to adjust the measured gas to a set temperature and pressure, allowing it to flow at a constant volume flow rate through a capillary tube of known inner diameter and length. The pressure difference across the capillary tube is measured, and the gas viscosity is calculated using the Hagen-Poiseuille formula for laminar flow. The constancy of the gas state throughout the test and the stability of the volume flow rate are two basic prerequisites for ensuring accurate and reliable viscosity measurement results.

[0004] Chinese patent document CN111307663A discloses a gas viscosity measuring device, which includes a storage tank, a mass flow control assembly, a first pressure gauge, a first capillary tube, a second pressure gauge, and a second capillary tube connected in sequence by pipelines, as well as a first differential pressure gauge connected in parallel with the first capillary tube and a second differential pressure gauge connected in parallel with the second capillary tube; the first pressure gauge is used to measure the pressure at the inlet end of the first capillary tube, and the second pressure gauge is used to measure the pressure at the inlet end of the second capillary tube; the gas viscosity measuring device also includes a first thermostatic bath for maintaining a constant temperature of the gas in the first capillary tube, a first thermocouple for measuring the temperature of the gas in the first capillary tube, a second thermostatic bath for maintaining a constant temperature of the gas in the second capillary tube, and a second thermocouple for measuring the temperature of the gas in the second capillary tube.

[0005] The Chinese patent document with publication number CN109142152A discloses a double capillary viscometer for measuring the viscosity of acidic natural gas, which includes an inlet stop valve connected to a gas cylinder, a measuring pipeline connected to the inlet stop valve, a solid particle filter and a gas dryer connected in sequence, and an upstream inlet piezoelectric valve; along the main test pipeline, an upstream capillary, a mid-way piezoelectric valve, a downstream preheating capillary, a downstream test capillary, a downstream outlet piezoelectric valve, an outlet stop valve, and then an H2S absorption bottle, and finally a vacuum pump; the above test pipelines are divided into upstream Pipeline and downstream pipeline; wherein, the upstream capillary is spirally wound on a cylindrical aluminum block and immersed in an alcohol constant temperature device, and the downstream preheating capillary and the downstream test capillary are immersed in a silicone oil constant temperature device in the same way; an upstream inlet pressure gauge is connected after the upstream inlet piezoelectric valve, and an upstream outlet pressure gauge is installed in front of the mid-way piezoelectric valve, and the two pressure gauges are connected with an upstream differential pressure gauge; a downstream inlet pressure gauge is installed between the downstream preheating capillary and the downstream test capillary, and a downstream outlet pressure gauge is installed in front of the downstream outlet piezoelectric valve, and the two pressure gauges are connected with a downstream differential pressure gauge.

[0006] To achieve gas state regulation and flow control, gas viscosity measurement devices use components such as pressure reducing valves and back-pressure valves. A dual-capillary viscometer for measuring the viscosity of sour natural gas uses a piezoelectric valve with control logic. However, both of the above solutions have two problems: first, the dynamic change in valve opening when adjusting the pressure reducing valve or piezoelectric valve causes the gas state in the capillary to change during the test; second, the flow in the pipeline is affected by the compressibility of the gas, making it difficult to maintain stability.

[0007] Chinese patent publication CN110646567A discloses a PVT testing device and method suitable for ultrahigh-pressure, high-temperature viscosity measurement. The device consists of two upper and lower PVT cylinders, a high-definition camera, a capillary viscosity tester, a sealed piston cylinder, and a high-temperature oven, the device being located within the oven. The upper PVT cylinder has a displacement rod with a piston and a grating scale, with the displacement rod's advance measured by the grating scale. The lower PVT cylinder has a rigid direct drive with a piston, each piston having a protruding tip. The displacement rod is connected to the rigid direct drive via a balanced pressure line and a control valve, and the displacement movement is driven by the pressure transmitted by the balanced pressure line. Both the displacement rod and the rigid direct drive are connected to a magnetically driven agitator. The upper and lower PVT cylinders have glass windows and a channel hole, with the channel hole facing the high-definition camera. A pneumatic isolation valve is located between the upper and lower PVT cylinders. The capillary viscosity tester connects to the interior spaces of the upper and lower PVT cylinders via a three-way valve and a pressure gauge. A sealed piston cylinder connects to the interior space of the upper PVT cylinder via a pressure gauge and a three-way valve. The sealed piston cylinder has a rigid direct drive with a piston. Using two facing PVT cylinders with pistons, the test fluid is introduced into the interconnected PVT cylinders and capillary tube via an external high-pressure pipeline.

[0008] This system utilizes two PVT cylinders with pistons placed face-to-face. The test fluid is introduced into the interconnected PVT cylinder and capillary tube via an external high-pressure line. An additional balanced pressure line drives the piston, causing the test fluid to flow through the capillary tube for viscosity testing. To ensure consistent fluid flow and flow in the test lines, the medium pressure in the balanced pressure line must be sufficiently high and stable.

[0009] Chinese patent document publication number CN113567302A discloses an ultra-high temperature and high pressure oil and gas fluid viscosity meter and its use method, which includes a high-pressure cavity and an external pressure system. The interior of the high-pressure cavity is axially configured as an open cavity, and the ports on both sides of the high-pressure cavity are sealed with end face covers. A through hole is opened in the middle of the end faces of the two end face covers. Three through holes are provided in the middle of the top of the outside of the high-pressure cavity. The high-pressure pipeline of the external pressure system is connected to the five through holes of the high-pressure cavity. The through holes are all high-pressure fluid channels. A heating jacket is provided around the outer side of the high-pressure cavity.

[0010] It connects two high-pressure chambers on both sides of the capillary, and uses two high-pressure displacement pumps and hydraulic oil to push the high-pressure chamber piston, allowing the test gas to enter the capillary for viscosity testing. In order to keep the state and flow of the test gas in the capillary constant, the high-pressure displacement pump needs to increase the thrust sufficiently high and maintain a synchronous operating speed.

[0011] A PVT testing device and method suitable for ultra-high pressure and high temperature viscosity measurement, as well as an ultra-high temperature and high pressure oil and gas fluid viscosity meter and its use method, use a balanced pressure pipeline or a high-pressure displacement pump to increase the complexity and operation difficulty of the test system, thereby affecting the accuracy of the viscosity test.

[0012] Currently, the existing publicly available viscosity testing methods are only applicable to viscosity testing of gases under pressure higher than normal pressure. There is still no effective testing device and method for the viscosity of gases under negative pressure. Summary of the Invention

[0013] The present invention provides a testing device and method for gas viscosity under multiple working conditions, which overcomes the shortcomings of the above-mentioned existing technologies and can effectively solve the problems of existing gas viscosity testing devices such as adjustment of gas state before testing, changes in gas state during testing, and unstable volume flow control.

[0014] One of the technical solutions of the present invention is achieved through the following measures: a test device for the viscosity of gases under multiple working conditions, comprising a constant temperature box, a capillary, a driving mechanism, and a first cylinder and a second cylinder with the same structure and arranged in opposite directions. A driving mechanism is provided between the right end of the piston rod of the first cylinder and the left end of the piston rod of the second cylinder. The driving mechanism enables the piston rods of the first cylinder and the piston rods of the second cylinder to move synchronously in the same direction. A first air inlet and a first air outlet are provided on the outer side of the first cylinder at intervals, and the first air inlet and the first air outlet are connected to each other inside and outside. They are both connected to the rodless cavity of the first cylinder. A second air inlet and a second air outlet that are connected inside and outside are provided at intervals on the outside of the second cylinder. The second air inlet and the second air outlet are both connected to the rodless cavity of the second cylinder. A capillary is provided in the constant temperature box. A first test pipeline is fixedly connected between the first end of the capillary and the first air outlet. An emptying pipeline is fixedly connected on the first test pipeline, and an emptying valve is installed on the emptying pipeline. A second test pipeline is fixedly connected between the second end of the capillary and the second air outlet. A differential pressure gauge is provided between the first end and the second end of the capillary.

[0015] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0016] The above-mentioned device may further include a first four-way valve and a second four-way valve. A buffer gas tank is provided in the constant temperature box. The gas outlet of the buffer gas tank is fixedly connected to the first end of the capillary tube. The first test pipeline is fixedly connected between the gas inlet of the buffer gas tank and the first port of the first four-way valve. A third test pipeline is fixedly connected between the second port of the first four-way valve and the first gas outlet. A fourth test pipeline is fixedly connected between the third test pipeline and the third port of the first four-way valve. A first exhaust check valve is installed on the fourth test pipeline.

[0017] The second test line is fixedly connected between the second end of the capillary tube and the first port of the second four-way valve. A fifth test line is fixedly connected between the second port of the second four-way valve and the second gas outlet. A sixth test line is fixedly connected between the fifth test line and the third port of the second four-way valve. A second exhaust check valve is installed on the sixth test line.

[0018] The fourth port of the first four-way valve is fixedly connected to the first air intake pipeline, and the air intake valve is installed on the first air intake pipeline. The second air intake pipeline is fixedly connected between the first air intake pipeline corresponding to the position between the air intake valve and the first four-way valve and the fourth port of the second four-way valve. The third air intake pipeline is fixedly connected between the first air intake pipeline corresponding to the position between the second air intake pipeline and the first four-way valve and the first air inlet, and the first air intake check valve is installed on the third air intake pipeline. The fourth air intake pipeline is fixedly connected between the second air intake pipeline and the second air inlet, and the second air intake check valve is installed on the fourth air intake pipeline.

[0019] The fourth test pipeline corresponding to the position between the first exhaust check valve and the first four-way valve can be fixedly connected to a first pressure relief pipe, and the first pressure relief valve is installed on the first pressure relief pipe. The sixth test pipeline corresponding to the position between the second exhaust check valve and the second four-way valve is fixedly connected to a second pressure relief pipe, and the second pressure relief valve is installed on the second pressure relief pipe.

[0020] The above-mentioned constant temperature box may include a thermostat, a temperature controller and a box body. The buffer gas tank, capillary tube and thermostat are fixedly installed in the box body at intervals. A temperature sensor is provided in the box body. The temperature sensor and thermostat are both connected to the temperature controller. Insulation layers are provided on the outside of the box body, the outside of the first cylinder and the outside of the second cylinder.

[0021] The above-mentioned driving mechanism may include a driving motor and a screw, the output shaft of the driving motor is connected to the middle part of the screw, and the two ends of the screw are respectively detachably fixed to the right end of the piston rod of the first cylinder and the left end of the piston rod of the second cylinder.

[0022] The second technical solution of the present invention is achieved by the following measures: a method for testing the viscosity of a gas under multiple working conditions, comprising the following steps:

[0023] Step 1: Connect the end of the first air inlet line to the air source;

[0024] Step 2: Close the first pressure relief valve, the second pressure relief valve, and the exhaust valve, open the air inlet valve, and control the first four-way valve and the second four-way valve, so that gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube, and the rodless cavity of the second cylinder; open the exhaust valve, so that the driving mechanism drives the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right;

[0025] Step 3: Close the drain valve, open the thermostat and temperature controller, make the temperature inside the box reach the test temperature and keep it constant, and close the air inlet valve;

[0026] Step 4: When the pressure in the buffer gas tank reaches the target value, the motor is driven to move the lead screw to the right or left at a set speed V;

[0027] Step 5: Record the differential pressure gauge reading ΔP on both sides of the capillary tube, and calculate the flow rate Q=VA based on the set speed V and the cross-sectional area A of the first cylinder;

[0028] Step 6: Calculate the gas viscosity μ according to the following formula:

[0029]

[0030] in is the capillary radius, is the capillary length, is the pressure difference, is the volume flow rate;

[0031] Step 7: Change the set speed of the screw and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0032] Step 8: Compare and analyze multiple groups of test results to obtain accurate gas viscosity values.

[0033] The following is a further optimization and / or improvement of the second technical solution of the above invention:

[0034] As the first preferred embodiment, the above-mentioned step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the exhaust valve, open the air intake valve, the first port and the second port of the first four-way valve, the first port and the second port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube and the rodless cavity of the second cylinder; open the exhaust valve, and drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right.

[0035] As a second preference, the above-mentioned step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the drain valve, open the air intake valve, the first port and the third port of the first four-way valve, the first port and the third port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube and the rodless cavity of the second cylinder; start the drive motor, and the drive motor drives the piston rod of the first cylinder and the piston rod of the second cylinder to reciprocate left and right, and the rodless cavity of the first cylinder and the rodless cavity of the second cylinder periodically inhale and exhaust, so that the gas pressure in the first test pipeline is greater than the target value; open the drain valve, and the drive motor drives the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or synchronously to the right.

[0036] As a third preference, the above-mentioned step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the exhaust valve, open the intake valve, the first port and the third port of the first four-way valve, the first port and the third port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary and the rodless cavity of the second cylinder; open the exhaust valve, drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right; close the intake valve, open the first port and the fourth port of the first four-way valve, the first port and the fourth port of the second four-way valve, the first pressure relief valve and the second pressure relief valve, drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right, the rodless cavity of the first cylinder and the rodless cavity of the second cylinder inhale gas from the first test pipeline, and discharge the gas through the first pressure relief pipe and the second pressure relief pipe, and the pressure of the first test pipeline is greater than the set negative pressure value.

[0037] The present invention has a reasonable and compact structure. It employs coaxial, equal-diameter twin cylinders (a first cylinder and a second cylinder) mounted opposite each other to address two issues encountered in capillary tube testing of gas viscosity: First, gas state adjustment. A drive mechanism is used to achieve left-right movement of the piston rod, thereby changing the volume of the rodless chamber of the cylinder. When the volume of the rodless chamber decreases, the gas is pressurized, and when the volume of the rodless chamber increases, the gas is depressurized. This allows the drive mechanism and cylinders to achieve pressurization or depressurization, thereby bringing the gas to a set pressure. A constant temperature chamber is then used to maintain the gas at a set temperature. Second, a constant gas state is maintained during testing. During testing, the first and second cylinders are connected to the capillary tube to form a closed test loop. The pistons of the two cylinders exert synchronous, uniform push / pull forces on the gas at opposite speeds. The gas volume in the test loop remains constant, achieving quasi-steady-state flow and ensuring a constant gas state. Changing the piston speeds of the two cylinders can also adjust the gas flow rate in the test loop, meeting the need for multiple tests under the same gas state and improving the accuracy of gas viscosity test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Attachment Figure 1 Schematic diagram of the structures of embodiments 1 to 7 of the present invention.

[0039] Attachment Figure 2 The main cross-sectional view of the driving mechanism in the fifth embodiment of the present invention is shown in FIG. Figure 1 .

[0040] Attachment Figure 3 The main cross-sectional view of the driving mechanism in the fifth embodiment of the present invention is shown in FIG. Figure 2 .

[0041] The codes in the accompanying drawings are: 1 for the box, 2 for the capillary tube, 3 for the first cylinder, 4 for the second cylinder, 5 for the first test line, 6 for the emptying line, 7 for the emptying valve, 8 for the second test line, 9 for the differential pressure gauge, 10 for the first four-way valve, 11 for the second four-way valve, 12 for the buffer gas tank, 13 for the third test line, 14 for the fourth test line, 15 for the first exhaust check valve, 16 for the fifth test line, 17 for the sixth test line, 18 for the second exhaust check valve, 19 for the sixth test line, 20 for the seventh test line, 21 for the eighth test line, 22 for the eighth test line, 23 for the eighth test line, 24 for the eighth test line, 25 for the eighth test line, 26 for the eighth test line, 27 for the eighth test line, 28 for the eighth test line, 29 for the eighth test line, 30 for the eighth test line, 31 for the eighth test line, 32 for the eighth test line, 33 for the eighth test line, 34 for the eighth test line, 35 for the eighth test line, 36 for the eighth test line, 37 for the eighth test line, 38 for the eighth test line, 39 for the eighth test line, 40 for the eighth test line, 41 for the eighth test line, 42 for the eighth test line, 43 for the eighth test line, 44 for the eighth test line, 45 for the eighth test line, 46 for the eighth test line, 47 for the eighth test line, 48 for the eighth test line, 49 for the eighth test line, 50 for the eighth test line, 51 for the eighth test line, 52 for the eighth test line, 53 for the eighth test line, 54 for the eighth test line, 55 for the eighth test line, 56 for the eighth test line, 57 for the 9 is the first air intake pipeline, 20 is the air intake valve, 21 is the second air intake pipeline, 22 is the third air intake pipeline, 23 is the first air intake check valve, 24 is the fourth air intake pipeline, 25 is the second air intake check valve, 26 is the first pressure relief pipe, 27 is the first pressure relief valve, 28 is the second pressure relief pipe, 29 is the second pressure relief valve, 30 is the thermostat, 31 is the temperature controller, 32 is the temperature sensor, 33 is the insulation layer, 34 is the screw, 35 is the drive motor, 36 is the base, and 37 is the reducer. DETAILED DESCRIPTION

[0042] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0043] In the present invention, for the convenience of description, the relative position relationship of each component is described based on the Figure 1 The layout is described in detail, such as the positional relationships of front, back, top, bottom, left, and right are based on the Figure 1 The layout direction is determined by the

[0044] The present invention will be further described below in conjunction with the embodiments and accompanying drawings:

[0045] Example 1: As shown in the attached Figure 1 As shown, the test device for the viscosity of gases under multiple working conditions includes a constant temperature box, a capillary 2, a driving mechanism, and a first cylinder 3 and a second cylinder 4 with the same structure and arranged back to back. A driving mechanism is provided between the right end of the piston rod of the first cylinder 3 and the left end of the piston rod of the second cylinder 4. The driving mechanism enables the piston rods of the first cylinder 3 and the second cylinder 4 to move synchronously in the same direction. A first air inlet and a first air outlet that are connected to the outside of the first cylinder 3 are provided at intervals. The first air inlet and the first air outlet are both connected to the rodless cavity of the first cylinder 3. A second air inlet and a second air outlet that are connected inside and outside are provided on the outside of the second cylinder 4. The second air inlet and the second air outlet are both connected to the rodless cavity of the second cylinder 4. A capillary 2 is provided in the constant temperature box. A first test pipeline 5 is fixedly connected between the first end of the capillary 2 and the first air outlet. An emptying pipeline 6 is fixedly connected to the first test pipeline 5, and an emptying valve 7 is installed on the emptying pipeline 6. A second test pipeline 8 is fixedly connected between the second end of the capillary 2 and the second air outlet. A differential pressure gauge 9 is provided between the first end and the second end of the capillary 2.

[0046] The first cylinder 3 and the second cylinder 4 are arranged back to back, that is, when the piston rod of the first cylinder 3 moves to the right, the volume of the rodless chamber of the first cylinder 3 increases, and at the same time, the piston rod of the second cylinder 4 moves to the right, the volume of the rodless chamber of the second cylinder 4 decreases. Conversely, when the piston rod of the first cylinder 3 moves to the left, the volume of the rodless chamber of the first cylinder 3 decreases, and at the same time, the piston rod of the second cylinder 4 moves to the left, the volume of the rodless chamber of the second cylinder 4 increases.

[0047] According to requirements, the inner diameter of the capillary tube 2 is 0.75 to 2 mm, and the length is 3 to 5 m. A connecting pipe is fixedly connected between the left and right ends of the capillary tube 2, and a differential pressure gauge 9 is installed on the connecting pipe. The pressure bearing capacity of the first cylinder 3 and the second cylinder 4 is not less than 200 MPa.

[0048] This application adopts coaxial equal-diameter double cylinders (first cylinder 3 and second cylinder 4) installed in opposite directions, which can solve two problems in the capillary method test of gas viscosity: one is the adjustment of the gas state, which uses the driving mechanism to realize the left and right movement of the piston rod, thereby changing the volume of the rodless chamber of the cylinder. When the volume of the rodless chamber decreases, the gas pressurization effect is achieved, and when the volume of the rodless chamber increases, the gas decompression effect is achieved. In this way, the driving mechanism and the cylinder can be used to realize the pressurization or decompression function, so that the gas reaches the set pressure, and the constant temperature box is used to make the gas reach the set temperature; the second is the test process The gas state is maintained constant. During the test, the first cylinder 3 and the second cylinder 4 are connected to the capillary 2 to form a closed test loop. The pistons of the two cylinders produce synchronous and constant push / pull reverse effects on the gas (when one cylinder produces a push effect on the gas, the other cylinder produces a synchronous and constant pull effect on the gas). The gas volume in the test loop remains unchanged, achieving quasi-steady-state flow and ensuring a constant gas state. Changing the piston movement speed of the two cylinders can also adjust the gas flow in the test loop, meeting the needs of conducting multiple groups of tests under the same gas state, thereby improving the accuracy of the gas viscosity test results.

[0049] The above-mentioned test device for gas viscosity under multiple working conditions can be further optimized and / or improved according to actual needs:

[0050] Example 2: As an optimization of the above example, as shown in the attached Figure 1 As shown, it also includes a first four-way valve 10 and a second four-way valve 11. A buffer gas tank 12 is provided in the constant temperature box. The gas outlet of the buffer gas tank 12 is fixedly connected to the first end of the capillary 2. The first test pipeline 5 is fixedly connected between the gas inlet of the buffer gas tank 12 and the first port of the first four-way valve 10. A third test pipeline 13 is fixedly connected between the second port of the first four-way valve 10 and the first gas outlet. A fourth test pipeline 14 is fixedly connected between the third test pipeline 13 and the third port of the first four-way valve 10. A first exhaust one-way valve 15 is installed on the fourth test pipeline 14.

[0051] The second test pipeline 8 is fixedly connected between the second end of the capillary tube 2 and the first port of the second four-way valve 11. A fifth test pipeline 16 is fixedly connected between the second port of the second four-way valve 11 and the second gas outlet. A sixth test pipeline 17 is fixedly connected between the fifth test pipeline 16 and the third port of the second four-way valve 11. A second exhaust check valve 18 is installed on the sixth test pipeline 17.

[0052] The fourth port of the first four-way valve 10 is fixedly connected to the first air intake pipeline 19, on which an air intake valve 20 is installed. A second air intake pipeline 21 is fixedly connected between the first air intake pipeline 19 corresponding to the position between the air intake valve 20 and the first four-way valve 10 and the fourth port of the second four-way valve 11. A third air intake pipeline 22 is fixedly connected between the first air intake pipeline 19 corresponding to the position between the second air intake pipeline 21 and the first four-way valve 10 and the first air inlet, and a first air intake check valve 23 is installed on the third air intake pipeline 22. A fourth air intake pipeline 24 is fixedly connected between the second air intake pipeline 21 and the second air inlet, and a second air intake check valve 25 is installed on the fourth air intake pipeline 24.

[0053] As required, the first four-way valve 10, the second four-way valve 11, the first exhaust check valve 15, the second exhaust check valve 18, the first intake check valve 23, and the second intake check valve 25 are all conventionally known technologies. During use, the first four-way valve 10 and the second four-way valve 11 can be used to connect the other end of the first intake pipeline 19 to a different gas source. When the gas source is high-pressure, the first port of the first four-way valve 10 is connected to the second port, and the first port of the second four-way valve 11 is connected to the second port. The intake valve 20 is opened, and the high-pressure gas enters the rodless chamber of the first cylinder 3, the third test line 13, the first test line 5, and the capillary tube 2 through the third intake line 22. Simultaneously, it enters the rodless chamber of the second cylinder 4, the fifth test line 16, the second test line 8, and the capillary tube 2 through the fourth intake line 24.

[0054] When the gas source is a low-pressure mixture, the first port of the first four-way valve 10 is connected to the third port, the first port of the second four-way valve 11 is connected to the third port, the intake valve 20 is opened, and the low-pressure mixture enters the rodless cavity of the first cylinder 3, the fourth test pipeline 14, the first test pipeline 5 and the capillary 2 through the third intake pipeline 22, and at the same time enters the rodless cavity of the second cylinder 4, the sixth test pipeline 17, the second test pipeline 8 and the capillary 2 through the fourth intake pipeline 24.

[0055] Depending on the test method, the gas source can be a low-pressure mixed gas or a high-pressure gas source. The high-pressure gas source can be online gas from an industrial pipeline / device, or high-pressure gas generated by a booster device.

[0056] Example 3: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the fourth test pipeline 14 corresponding to the position between the first exhaust check valve 15 and the first four-way valve 10 is fixedly connected to a first pressure relief pipe 26, and a first pressure relief valve 27 is installed on the first pressure relief pipe 26. The sixth test pipeline 17 corresponding to the position between the second exhaust check valve 18 and the second four-way valve 11 is fixedly connected to a second pressure relief pipe 28, and a second pressure relief valve 29 is installed on the second pressure relief pipe 28.

[0057] When the gas source is a low-pressure mixed gas, the first port of the first four-way valve 10 is connected to the fourth port, and the first port of the second four-way valve 11 is connected to the fourth port. The air intake valve 20 is opened, and the low-pressure mixed gas enters the first test pipeline 5 and the capillary 2 through the first air intake pipeline 19, and enters the second test pipeline 8 and the capillary 2 through the second air intake pipeline 21. Then the first pressure relief valve 27 and the second pressure relief valve 29 are opened, and the driving mechanism drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move back and forth left and right. When the driving mechanism drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move to the left, the volume of the rodless chamber of the first cylinder 3 decreases, and the volume of the rodless chamber of the second cylinder 4 increases. The gas in the second test pipeline 8 is sucked into the rodless chamber of the second cylinder 4.

[0058] When the driving mechanism drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move to the right, the volume of the rodless chamber of the first cylinder 3 increases, and the gas in the first test pipeline 5 is sucked into the rodless chamber of the first cylinder 3. At the same time, the volume of the rodless chamber of the second cylinder 4 decreases, and the gas in the rodless chamber of the second cylinder 4 is discharged through the second pressure relief pipe 28.

[0059] When the driving mechanism drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move to the left again, the volume of the rodless chamber of the first cylinder 3 decreases, and the gas in the rodless chamber of the first cylinder 3 is discharged through the first pressure relief pipe 26. At the same time, the volume of the rodless chamber of the second cylinder 4 increases, and the gas in the second test pipeline 8 is sucked into the rodless chamber of the second cylinder 4 again. This cycle repeats, and the gas in the first test pipeline 5, the second test pipeline 8 and the capillary tube 2 decreases, and the pressure decreases until the set negative pressure value is reached.

[0060] Example 4: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the constant temperature box includes a thermostat 30, a temperature controller 31 and a box body 1. The buffer gas tank 12, the capillary tube 2 and the thermostat 30 are fixedly installed in the box body 1 at intervals. A temperature sensor 32 is provided in the box body 1. The temperature sensor 32 and the thermostat 30 are both connected to the temperature controller 31. An insulation layer 33 is provided on the outside of the box body 1, the outside of the first cylinder 3 and the outside of the second cylinder 4.

[0061] According to the needs, the thermostat 30 is an existing well-known technology, such as an electric heater, a heat exchanger and a refrigerator. The thermostat has heating and cooling functions, and the temperature control range is -40 to 220°C. It is suitable for testing the viscosity of multi-working gas. The test pipeline in contact with the air, the outside of the box 1, the surface of the first cylinder 3, the surface of the second cylinder 4 and the surface of the valve body are all provided with an insulation layer 33, and the buffer gas tank 12 is provided with a pressure gauge to facilitate testing the gas pressure. During use, through such a setting, the temperature environment of the buffer gas tank 12 and the capillary 2 is kept constant, reducing the impact of temperature changes on the gas in the pipeline during the test, and can improve the accuracy of the test results.

[0062] Example 5: As an optimization of the above embodiment, as shown in the attached Figure 1 、 2 As shown in Figure 3, the driving mechanism includes a driving motor 35 and a screw 34. The output shaft of the driving motor 35 is connected to the middle part of the screw 34 through transmission. The two ends of the screw are respectively detachably fixed to the right end of the piston rod of the first cylinder 3 and the left end of the piston rod of the second cylinder 4.

[0063] According to the requirements, the drive motor 35 and the lead screw 34 form an existing well-known through-type lead screw stepper motor (such as a through-type ball screw stepper motor disclosed in the Chinese patent document with the announcement number CN217240551U, which can make the ball screw reciprocating positioning accuracy of about 0.03mm, and input the motor through the pulse signal), as shown in the attached Figure 1 As shown, a base (not shown in the figure) is fixedly installed on the lower side of the driving motor 35, the upper left side of the base is fixedly installed together with the lower side of the first cylinder 3, and the upper right side of the base is fixedly installed together with the lower side of the second cylinder 4. The left end of the screw 34 is rotatably installed together with the right end of the piston rod of the first cylinder 3 (rotatably installed together through an existing well-known rotary joint), and at the same time, the right end of the screw 34 is rotatably installed together with the left end of the piston rod of the second cylinder 4. In this way, when the screw 34 moves left and right (spiral motion), it can drive the piston rods of the first cylinder 3 and the piston rods of the second cylinder 4 to move synchronously in the same direction.

[0064] Or, as attached Figure 2As shown, the driving mechanism includes a driving motor (not shown in the figure) and a screw 34, a base 36 is fixedly installed on the lower side of the driving motor, the upper left side of the base 36 is fixedly installed with the lower side of the first cylinder 3, and the upper right side of the base 36 is fixedly installed with the lower side of the second cylinder 4, a reducer 37 is provided at the rear of the driving motor 35, and the reducer 37 is an existing well-known dual-output shaft reducer, the rear end of the output shaft of the driving motor and the front end of the input shaft of the reducer 37 are connected together by a coupling, and the two output shaft ends of the dual-output shaft reducer are fixedly installed with screws, the right end of the piston rod of the first cylinder 3 is fixedly installed with a first screw nut, the first screw nut is threadedly connected to the outer side of the left screw 34, and the left end of the piston rod of the second cylinder 4 is fixedly installed with a second screw nut, the second screw nut is threadedly connected to the outer side of the right screw 34, in order to prevent the first screw nut and the second screw nut from rotating with the screw 34, the lower side of the first screw nut and the lower side of the second screw nut are in contact with each other on the upper side of the base 36, and can also be attached Figure 3 As shown, a first guide rod parallel to the left lead screw 34 is provided in the first lead screw nut, and a second guide rod parallel to the right lead screw 34 is provided in the second lead screw nut. The left and right ends of the first guide rod are fixedly mounted between the right end of the first cylinder 3 and the left side of the reducer 37, and the left and right ends of the second guide rod are fixedly mounted on the right side of the reducer 37 and between the left end of the second cylinder 4. In this way, the driving motor drives the lead screws on both sides to rotate through the reducer 37, so that the first lead screw nut and the second lead screw nut move to the left or to the right at the same time. The rotation of the driving motor 35 can be driven by the existing well-known RCmf stepper motor driver, so that the stepper motor running through the lead screw 34 can convert the rotational motion into the linear reciprocating motion of the two cylinder pistons.

[0065] This application has the following technical effects:

[0066] First, by using the first cylinder 3 and the second cylinder 4, the gas in the first test pipeline and the second test pipeline can be pressurized or depressurized, so that the gas reaches the set high pressure or negative pressure state, meeting the needs of various working condition tests. This device can test the viscosity of gases with a temperature range of -40 to 220°C and a pressure (gauge pressure) range of -0.098MPa to 200MPa.

[0067] Second, the gas state is maintained constant during the test. During the test, the first cylinder 3 and the second cylinder 4 are connected to the capillary 2 to form a closed test loop. The pistons of the first cylinder 3 and the second cylinder 4 produce synchronous and constant push / pull reverse effects on the gas. The gas volume in the test loop remains unchanged, achieving quasi-steady-state flow and ensuring a constant gas state. Changing the piston movement speed can also adjust the gas flow in the test loop to meet the needs of conducting multiple groups of tests under the same gas state, thereby improving the accuracy of the gas viscosity test results.

[0068] Third, the coaxial first cylinder 3 and the second cylinder 4 of equal diameter are installed back to back, and the piston rods of the first cylinder 3 and the second cylinder 4 are connected to the screw, which can ensure the precise synchronous movement of the two pistons; and the gas force acting on the end faces of the pistons connected at both ends of the screw is balanced, so the driving motor 35 only needs to overcome a small friction force to achieve precise and stable reciprocating linear motion of the screw 34, reducing the complexity and operation difficulty of the test system.

[0069] Example 6: As shown in the attached Figure 1 As shown, the multi-condition gas viscosity testing method includes the following steps:

[0070] Step 1: Connect the end of the first air inlet line 19 to the air source;

[0071] Step 2: Close the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7, open the air inlet valve 20, the first port and the second port of the first four-way valve 10, and the first port and the second port of the second four-way valve 11, and the gas enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2 and the rodless cavity of the second cylinder 4;

[0072] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right;

[0073] Step 3: Close the drain valve 7, open the thermostat 30 and the temperature controller 31, so that the temperature in the box 1 reaches the test temperature and remains constant, and close the air inlet valve 20;

[0074] Step 4: When the pressure in the buffer gas tank 12 reaches the target value, the motor 35 is driven to move the lead screw 34 to the right or left at a set speed V;

[0075] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2, and calculate the flow rate Q=VA based on the set speed V and the cross-sectional area A of the first cylinder 3;

[0076] Step 6: Calculate the gas viscosity μ according to the following formula (Hagen-Poiseuille formula):

[0077]

[0078] in is the radius of capillary 2, is the length of capillary 2, is the pressure difference, is the volume flow rate;

[0079] Step 7: Change the set speed of the screw 34 and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0080] Step 8: Compare and analyze multiple groups of test results to obtain accurate gas viscosity values.

[0081] The gas source in this embodiment is a high-pressure gas source, and the viscosity test method using direct air intake from the high-pressure gas source is adopted:

[0082] The first step is to check and close all valves and connect the end of the first air inlet line 19 to the air source;

[0083] In the second step, the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7 are closed, and the air inlet valve 20, the first port and the second port of the first four-way valve 10, and the first port and the second port of the second four-way valve 11 are opened, so that the gas enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2 and the rodless cavity of the second cylinder 4;

[0084] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right to discharge the impurity gas in the test pipeline and the cylinder;

[0085] In the third step, after the impurity gas is exhausted, the exhaust valve 7 is closed, the thermostat 30 and the temperature controller 31 are opened, so that the temperature in the box 1 reaches the test temperature and remains constant, and the air inlet valve 20 is closed;

[0086] Step 4: Set the speed of the drive motor 35. The drive motor 35 causes the screw 34 to move rightward or leftward at the set speed V. When the screw 34 moves rightward, the second cylinder 4 slowly exhausts air while the first cylinder 3 slowly inhales air. When the screw 34 moves leftward, the first cylinder 3 slowly exhausts air while the second cylinder 4 slowly inhales air, thereby achieving a quasi-steady state. In this way, the gas volume and state in the test pipeline remain unchanged during the test.

[0087] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2 and calculate the flow rate Q=VA based on the piston movement speed, i.e., the set speed V of the screw 34 and the cross-sectional area A of the first cylinder 3;

[0088] Step 6: Calculate the gas viscosity corresponding to the flow rate in step 5 according to the Hagen-Poiseuille formula;

[0089] Step 7: Change the speed of the drive motor 35 to change the set speed of the lead screw 34, and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0090] Step 8: Compare and analyze multiple test results to obtain accurate gas viscosity values;

[0091] Step 9: After the test is completed, turn off the drive motor 35 and open the exhaust valve 7 to release the gas.

[0092] Example 7: As shown in the attached Figure 1 As shown, the multi-condition gas viscosity testing method includes the following steps:

[0093] Step 1: Connect the end of the first air inlet line 19 to the air source;

[0094] Step 2: Close the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7, open the air inlet valve 20, the first port and the third port of the first four-way valve 10, and the first port and the third port of the second four-way valve 11, and the gas enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2 and the rodless cavity of the second cylinder 4;

[0095] The drive motor 35 is started, and the drive motor 35 drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to reciprocate left and right. The rodless chamber of the first cylinder 3 and the rodless chamber of the second cylinder 4 periodically inhale and exhaust air, so that the gas pressure in the first test pipeline is greater than the target value;

[0096] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right;

[0097] Step 3: Close the drain valve 7, open the thermostat 30 and the temperature controller 31, so that the temperature in the box 1 reaches the test temperature and remains constant, and close the air inlet valve 20;

[0098] Step 4: When the pressure in the buffer gas tank 12 reaches the target value, the motor 35 is driven to move the lead screw 34 to the right or left at a set speed V;

[0099] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2, and calculate the flow rate Q=VA based on the set speed V and the cross-sectional area A of the first cylinder 3;

[0100] Step 6: Calculate the gas viscosity μ according to the following formula:

[0101]

[0102] in is the radius of capillary 2, is the length of capillary 2, is the pressure difference, is the volume flow rate;

[0103] Step 7: Change the set speed of the screw 34 and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0104] Step 8: Compare and analyze multiple groups of test results to obtain accurate gas viscosity values.

[0105] In this embodiment, the high-pressure gas viscosity test of the low-pressure mixed gas source adopts the method of first pressurizing and then performing the viscosity test:

[0106] The first step is to check and close all valves and connect the end of the first air inlet line 19 to the air source;

[0107] The second step is to close the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7, open the intake valve 20, the first port and the second port of the first four-way valve 10, the first port and the second port of the second four-way valve 11, start the drive motor 35, and the drive motor 35 drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to reciprocate left and right through the screw 34. When the screw 34 moves to the right, the second cylinder 4 slowly exhausts and the first cylinder 3 slowly inhales; when the screw 34 moves to the left, the first cylinder 3 slowly exhausts and the second cylinder 4 slowly inhales. The screw 34 reciprocates, and the first cylinder 3 and the second cylinder 4 continuously draws air from the gas source, inflates and pressurizes the buffer gas tank 12 and the capillary tube 2, so that the gas pressure is slightly higher than the test pressure; the two cylinders periodically inhale and exhaust air to pre-pressurize the gas in the test pipeline. During this process, the gas enters the rodless cavity of the first cylinder 3 through the first air inlet check valve 23, or enters the rodless cavity of the second cylinder 4 through the second air inlet check valve 25. Then, the two cylinder pistons move in opposite directions to compress the gas in the rodless cavity. The gas in the rodless cavity passes through the first exhaust check valve 15 and the second exhaust check valve 18 respectively and enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2, and the rodless cavity of the second cylinder 4;

[0108] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right to discharge the impurity gas in the test pipeline and the cylinder;

[0109] In the third step, after the impurity gas is exhausted, the exhaust valve 7 is closed, the thermostat 30 and the temperature controller 31 are opened, so that the temperature in the box 1 reaches the test temperature and remains constant, and the air inlet valve 20 is closed;

[0110] Step 4: Open the first port and the second port of the first four-way valve 10, and simultaneously open the first port and the second port of the second four-way valve 11. At this time, the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2, and the rodless cavity of the second cylinder 4 are connected, and the gas pressure is the same and slightly higher than the test pressure. Slowly open the drain valve 7 to discharge part of the gas until the pressure gauge display reaches the test pressure. Close the drain valve 7, set the speed of the drive motor 35, and drive the motor 35 to move the screw 34 to the right or left at the set speed V;

[0111] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2 and calculate the flow rate Q=VA based on the piston movement speed, i.e., the set speed V of the screw 34 and the cross-sectional area A of the first cylinder 3;

[0112] Step 6: Calculate the gas viscosity corresponding to the flow rate in step 5 according to the Hagen-Poiseuille formula;

[0113] Step 7: Change the speed of the drive motor 35 to change the set speed of the lead screw 34, and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0114] Step 8: Compare and analyze multiple test results to obtain accurate gas viscosity values;

[0115] Step 9: After the test is completed, turn off the drive motor 35 and open the exhaust valve 7 to release the gas.

[0116] Example 8: As shown in the attached Figure 1 As shown, the multi-condition gas viscosity testing method includes the following steps:

[0117] Step 1: Connect the end of the first air inlet line 19 to the air source;

[0118] Step 2: Close the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7, open the air inlet valve 20, the first port and the third port of the first four-way valve 10, and the first port and the third port of the second four-way valve 11, and the gas enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary tube 2 and the rodless cavity of the second cylinder 4;

[0119] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right;

[0120] Close the air intake valve 20, open the first port and the fourth port of the first four-way valve 10, the first port and the fourth port of the second four-way valve 11, the first pressure relief valve 27 and the second pressure relief valve 29, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or to the right. The rodless chamber of the first cylinder 3 and the rodless chamber of the second cylinder 4 inhale gas from the first test pipeline, and discharge the gas through the first pressure relief pipe 26 and the second pressure relief pipe 28. The pressure of the first test pipeline is greater than the set negative pressure value.

[0121] Step 3: Close the drain valve 7, open the thermostat 30 and the temperature controller 31, so that the temperature in the box 1 reaches the test temperature and remains constant, and close the air inlet valve 20;

[0122] Step 4: When the pressure in the buffer gas tank 12 reaches the target value, the motor 35 is driven to move the lead screw 34 to the right or left at a set speed V;

[0123] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2, and calculate the flow rate Q=VA based on the set speed V and the cross-sectional area A of the first cylinder 3;

[0124] Step 6: Calculate the gas viscosity μ according to the following formula:

[0125]

[0126] in is the radius of capillary 2, is the length of capillary 2, is the pressure difference, is the volume flow rate;

[0127] Step 7: Change the set speed of the screw 34 and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0128] Step 8: Compare and analyze multiple groups of test results to obtain accurate gas viscosity values.

[0129] The gas source in this embodiment is a low-pressure mixed gas, and the method of first reducing the pressure and then performing the viscosity test is adopted:

[0130] The first step is to check and close all valves and connect the end of the first air inlet line 19 to the air source;

[0131] In the second step, the first pressure relief valve 27, the second pressure relief valve 29 and the drain valve 7 are closed, and the intake valve 20, the first port and the third port of the first four-way valve 10, and the first port and the third port of the second four-way valve 11 are opened, so that the gas enters the rodless cavity of the first cylinder 3, the buffer tank, the capillary tube 2 and the rodless cavity of the second cylinder 4;

[0132] Start the drive motor 35, and the screw 34 drives the two cylinder pistons to move back and forth. The two cylinders periodically inhale and exhaust air to pre-pressurize the gas in the test pipeline. During this process, the gas enters the rodless cavity of the first cylinder 3 through the first intake check valve 23, or enters the rodless cavity of the second cylinder 4 through the second intake check valve 25. Then, the two cylinder pistons reciprocate to compress the gas in the rodless cavity. After the gas in the rodless cavity is compressed and pressurized, it passes through the first exhaust check valve 15 and the second exhaust check valve 18 respectively and enters the rodless cavity of the first cylinder 3, the buffer gas tank 12, the capillary 2 and the first cylinder 3. In the rodless cavity of the second cylinder 4, the intake valve 20 is closed, the first port and the fourth port of the first four-way valve 10, the first port and the fourth port of the second four-way valve 11, the first pressure relief valve 27 and the second pressure relief valve 29 are opened, and the driving motor 35 drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or to the right. The rodless cavity of the first cylinder 3 and the rodless cavity of the second cylinder 4 inhale gas from the first test pipeline 5 and discharge the gas through the first pressure relief pipe 26 and the second pressure relief pipe 28, so that the pressure of the first test pipeline 5 is finally greater than the set negative pressure value;

[0133] Open the drain valve 7, and drive the motor 35 to drive the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or right to discharge the impurity gas in the test pipeline and the cylinder;

[0134] In the third step, after the impurity gas is exhausted, the exhaust valve 7 is closed, the thermostat 30 and the temperature controller 31 are opened, so that the temperature in the box 1 reaches the test temperature and remains constant, and the air inlet valve 20 is closed;

[0135] In the fourth step, the first port and the fourth port of the first four-way valve 10, the first port and the fourth port of the second four-way valve 11, the first pressure relief valve 27 and the second pressure relief valve 29 are opened, and the driving motor 35 drives the piston rod of the first cylinder 3 and the piston rod of the second cylinder 4 to move synchronously to the left or to the right. The rodless cavity of the first cylinder 3 and the rodless cavity of the second cylinder 4 inhale gas from the first test pipeline 5 and discharge the gas through the first pressure relief pipe 26 and the second pressure relief pipe 28. The pressure of the first test pipeline 5 is reduced until it reaches the set negative pressure value.

[0136] Set the speed of the drive motor 35 so that the lead screw 34 moves rightward or leftward at a set speed V;

[0137] Step 5: Record the reading ΔP of the differential pressure gauge 9 on both sides of the capillary tube 2 and calculate the flow rate Q=VA based on the piston movement speed, i.e., the set speed V of the screw 34 and the cross-sectional area A of the first cylinder 3;

[0138] Step 6: Calculate the gas viscosity corresponding to the flow rate in step 5 according to the Hagen-Poiseuille formula;

[0139] Step 7: Change the speed of the drive motor 35 to change the set speed of the lead screw 34, and repeat steps 4 to 6 to measure multiple sets of gas viscosities;

[0140] Step 8: Compare and analyze multiple test results to obtain accurate gas viscosity values;

[0141] Step 9: After the test is completed, turn off the drive motor 35 and open the exhaust valve 7 to release the gas.

[0142] The above technical features respectively constitute the embodiments of the present invention, which have strong adaptability and optimal implementation effects. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A device for testing gas viscosity under multiple working conditions, characterized in that The cam is connected to the air filter press, and the air filter presses ... It also includes a first four-way valve and a second four-way valve, a buffer gas tank is provided in the constant temperature box, the gas outlet of the buffer gas tank is fixedly connected to the first end of the capillary tube, a first test pipeline is fixedly connected between the gas inlet of the buffer gas tank and the first port of the first four-way valve, a third test pipeline is fixedly connected between the second port of the first four-way valve and the first gas outlet, a fourth test pipeline is fixedly connected between the third test pipeline and the third port of the first four-way valve, and a first exhaust check valve is installed on the fourth test pipeline; The second test line is fixedly connected between the second end of the capillary tube and the first port of the second four-way valve. A fifth test line is fixedly connected between the second port of the second four-way valve and the second gas outlet. A sixth test line is fixedly connected between the fifth test line and the third port of the second four-way valve. A second exhaust check valve is installed on the sixth test line. The fourth port of the first four-way valve is fixedly connected to the first air intake pipeline, and the air intake valve is installed on the first air intake pipeline. The second air intake pipeline is fixedly connected between the first air intake pipeline corresponding to the position between the air intake valve and the first four-way valve and the fourth port of the second four-way valve. The third air intake pipeline is fixedly connected between the first air intake pipeline corresponding to the position between the second air intake pipeline and the first four-way valve and the first air inlet, and the first air intake check valve is installed on the third air intake pipeline. The fourth air intake pipeline is fixedly connected between the second air intake pipeline and the second air inlet, and the second air intake check valve is installed on the fourth air intake pipeline.

2. The device for testing gas viscosity under multiple working conditions according to claim 1 is characterized in that A first pressure relief pipe is fixedly connected to the fourth test pipeline corresponding to the position between the first exhaust check valve and the first four-way valve, and a first pressure relief valve is installed on the first pressure relief pipe. A second pressure relief pipe is fixedly connected to the sixth test pipeline corresponding to the position between the second exhaust check valve and the second four-way valve, and a second pressure relief valve is installed on the second pressure relief pipe.

3. The device for testing gas viscosity under multiple working conditions according to claim 2, characterized in that The constant temperature box includes a thermostat, a temperature controller and a box body. The buffer gas tank, capillary tube and thermostat are fixedly installed in the box body at intervals. A temperature sensor is provided in the box body. The temperature sensor and thermostat are both connected to the temperature controller. Insulation layers are provided on the outside of the box body, the outside of the first cylinder and the outside of the second cylinder.

4. The device for testing gas viscosity under multiple working conditions according to claim 1 or 2, characterized in that The driving mechanism includes a driving motor and a screw. The output shaft of the driving motor is connected to the middle part of the screw. The two ends of the screw are detachably fixed to the right end of the piston rod of the first cylinder and the left end of the piston rod of the second cylinder respectively.

5. The device for testing gas viscosity under multiple working conditions according to claim 3 is characterized in that The driving mechanism includes a driving motor and a screw. The output shaft of the driving motor is connected to the middle part of the screw. The two ends of the screw are detachably fixed to the right end of the piston rod of the first cylinder and the left end of the piston rod of the second cylinder respectively.

6. A method for testing the viscosity of gases under multiple working conditions using the device for testing the viscosity of gases under multiple working conditions as claimed in claim 5, characterized in that The steps are as follows: Step 1: Connect the end of the first air inlet line to the air source; Step 2: Close the first pressure relief valve, the second pressure relief valve, and the exhaust valve, open the air inlet valve, and control the first four-way valve and the second four-way valve, so that gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube, and the rodless cavity of the second cylinder; open the exhaust valve, so that the driving mechanism drives the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right; Step 3: Close the drain valve, open the thermostat and temperature controller, make the temperature inside the box reach the test temperature and keep it constant, and close the air inlet valve; Step 4: When the pressure in the buffer gas tank reaches the target value, the motor is driven to move the lead screw to the right or left at a set speed V; Step 5: Record the differential pressure gauge reading ΔP on both sides of the capillary tube, and calculate the flow rate Q=VA based on the set speed V and the cross-sectional area A of the first cylinder; Step 6: Calculate the gas viscosity μ according to the following formula: in is the capillary radius, is the capillary length, ΔP is the pressure difference, is the volume flow rate; Step 7: Change the set speed of the screw and repeat steps 4 to 6 to measure multiple sets of gas viscosities; Step 8: Compare and analyze multiple groups of test results to obtain accurate gas viscosity values.

7. The method for testing the viscosity of a multi-condition gas according to claim 6, characterized in that Step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the exhaust valve, open the intake valve, the first port and the second port of the first four-way valve, the first port and the second port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube and the rodless cavity of the second cylinder; open the exhaust valve, and drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right.

8. The method for testing the viscosity of a multi-condition gas according to claim 6, characterized in that Step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the drain valve, open the intake valve, the first port and the third port of the first four-way valve, the first port and the third port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary and the rodless cavity of the second cylinder; start the drive motor, and the drive motor drives the piston rod of the first cylinder and the piston rod of the second cylinder to reciprocate left and right, and the rodless cavity of the first cylinder and the rodless cavity of the second cylinder periodically inhale and exhaust, so that the gas pressure in the first test pipeline is greater than the target value; open the drain valve, and the drive motor drives the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or right.

9. The method for testing the viscosity of a gas under multiple working conditions according to claim 6, characterized in that Step two is specifically as follows: close the first pressure relief valve, the second pressure relief valve and the exhaust valve, open the intake valve, the first port and the third port of the first four-way valve, the first port and the third port of the second four-way valve, and the gas enters the rodless cavity of the first cylinder, the buffer gas tank, the capillary tube and the rodless cavity of the second cylinder; open the exhaust valve, drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right; close the intake valve, open the first port and the fourth port of the first four-way valve, the first port and the fourth port of the second four-way valve, the first pressure relief valve and the second pressure relief valve, drive the motor to drive the piston rod of the first cylinder and the piston rod of the second cylinder to move synchronously to the left or to the right, the rodless cavity of the first cylinder and the rodless cavity of the second cylinder inhale gas from the first test pipeline, and discharge the gas through the first pressure relief pipe and the second pressure relief pipe, and the pressure of the first test pipeline is greater than the set negative pressure value.

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