Unit for testing aspirators

Abstract

FIELD: testing equipment.SUBSTANCE: invention relates to units for testing hand-held aspirators. The unit comprises a support on which a control tank (3) is secured, connected simultaneously to the atmosphere and to a seal tank (9) made open to the atmosphere. On the support (11) there is a fitting (8) for connecting the aspirator being tested (10), also connected to the control tank (3), and a drain fitting (5) with a shut-off valve (4) for draining the sealing liquid into the measuring tank. The connection between the shut-off (9) and control (3) tanks forms an overflow line that provides the overflow of the sealing liquid from the sealing tank (9) into the control tank (3) when a vacuum is created in the control tank (3) with the shut-off valve (2) closed during the working stroke of the aspirator being tested (10).EFFECT: increase in the reproducibility of verification results.3 cl, 5 dwg

Description

[0001] This invention relates to measurement technology and metrological support for air sampling devices, specifically to devices for calibrating hand-held aspirators (hand-held sampler pumps) that collect a single air sample per stroke. The invention can be used in certified laboratories, testing, and service departments for calibrating, monitoring the technical condition, and verifying the sample volume aspirated by hand-held aspirators.

[0002] The invention is intended for reproducing the volume of air extracted by the aspirator during the working stroke using the sealing liquid, and for subsequently determining the said volume based on the amount of displaced sealing liquid drained into a measuring container.

[0003] Patent RU 2780345 C1 discloses a manual air sampling pump for pumping air through an indicator tube. It contains elements that ensure the extraction of a specified volume of air and improve the extraction rate. This solution is similar in purpose to the object of application of the claimed device (the aspirator being verified); however, like RU 89701 U1, it is aimed at improving the design of the air sampling pump rather than creating an external verification device. Patent RU 2780345 C1 does not disclose the components for reproducing and measuring the air volume based on the volume of displaced liquid.

[0004] Patent RU 2625234 C1 discloses a device for collecting air samples in gas turbine engine nacelles. This solution shares the same purpose as the claimed solution in terms of collecting an air sample and operating at a specified volume / sampling mode. However, it pertains to a specialized aircraft sampling device, not to a setup for testing hand-held aspirators. The patent does not disclose a mechanical testing system with a sealing fluid, overflow tank, and graduated cylinder.

[0005] US Patent 11385096 B2 discloses an air flow calibrator (selected as a prototype) designed to verify / calibrate air samplers and pumps. This solution is the closest in purpose (selected as a prototype), as it is also designed to monitor the operating parameters of air aspiration devices. US Patent 11385096 B2 discloses measuring cells, a valve system, and means for recording flow parameters, including those using piston and bubble principles. The disadvantages of this solution, as applied to the claimed problem, include the complexity of the design, the use of electronic and optical measuring instruments, the focus primarily on measuring continuous flow rather than determining the air volume per stroke of a manual aspirator, and the lack of a simple two-capacity mechanical system with an overflow and direct discharge of the displaced liquid into a measuring container.

[0006] US Patent 5,635,637 A discloses a device for measuring liquid flow rate based on the mass / volume of liquid accumulated in a receiving vessel. This solution relates to flow metrology and demonstrates the use of a moving medium to determine flow parameters. However, it differs in its implementation principle, design, and intended use; it is not intended for testing hand-held aspirators and does not disclose the claimed set of features.

[0007] US Patents 6,763,710 B2 and NO 990921 L disclose flow measurement solutions based on microthermal and differential pressure principles, respectively. These solutions can be considered state-of-the-art in flow measurement; however, their design and functionality significantly differ from the claimed mechanical setup for testing aspirators and do not include any features for measuring air volume per stroke by displacing barrier fluid.

[0008] The technical objective of the invention is to create a simple, mobile, mechanical setup for testing manual aspirators. This setup measures the actual volume of air drawn in by the aspirator per stroke, with increased reproducibility of results, and allows operation with aspirators of various types and stroke volumes without the use of electronics or external power supply. The technical result consists of ensuring a reproducible volume of air drawn in per stroke of the aspirator based on the volume of displaced barrier fluid, and improving the ease of operation and maintenance of the setup through the use of a modular mechanical design.

[0009] The technical result is achieved in an installation for testing aspirators, comprising a support on which a control tank is secured, connected through a fitting and a shut-off valve to the atmosphere, as well as to a seal tank made open to the atmosphere, a fitting for connecting the aspirator being tested, connected to the control tank, and a drain fitting with a shut-off valve for draining the seal liquid into a measuring tank, wherein the connection between the seal and control tanks forms an overflow line, ensuring the overflow of the seal liquid from the seal tank into the control tank when creating a vacuum in the control tank with a closed shut-off valve connecting the control tank to the atmosphere, during the working stroke of the aspirator being tested, wherein the measuring tank is made in the form of a graduated graduated cylinder, and the support is made in the form of a mounting panel secured to the frame.

[0010] Brief description of the drawings:

[0011] Fig. 1 - external view of the installation for testing aspirators (three-dimensional image);

[0012] Fig. 2 - installation diagram before measuring the air volume with an aspirator;

[0013] Fig. 3 - diagram of the installation at the moment of compression of the aspirator;

[0014] Fig. 4 - diagram of the installation during the process of air intake by the aspirator;

[0015] Fig. 5 - diagram of the installation for measuring the volume of displaced sealing liquid.

[0016] The proposed setup is designed to reproduce the volume of an air sample collected by a manual aspirator 10 in a single stroke using a sealing fluid, and to subsequently determine said volume based on the volume of sealing fluid drained into a measuring container. In a preferred embodiment, support 11 is designed as a mounting panel attached to frame 12, ensuring stable placement of the components, mobility during movement within the room, and ease of access to each component for monitoring, maintenance, and cleaning. Frame 12 may be constructed as a free-standing welded metal structure.Mounted on support 11 are a nipple 1 for connecting test tank 3 to the atmosphere, a shut-off valve 2 in the line connecting to the atmosphere, a drain nipple 5 and a shut-off valve 4 for draining the sealing liquid into a measuring tank, a shut-off valve 6 in the line connecting to the aspirator, a shut-off valve 7 in the line connecting to the sealing tank 9, and a nipple 8 for connecting the aspirator being tested. Test tank 3 is connected to nipple 8 and to nipple 1 through corresponding lines with shut-off valves, which allows it to be switched from the mode of communication with the atmosphere to the mode of separation from the atmosphere and to create a vacuum in it during the working stroke of the aspirator.

[0017] Seal vessel 9 contains a seal fluid, preferably distilled water, and is open to the atmosphere, ensuring that the pressure on the free surface of the seal fluid in seal vessel 9 remains atmospheric. The connection between seal vessel 9 and control vessel 3 forms an overflow line, allowing seal fluid to flow from seal vessel 9 into control vessel 3 when a vacuum is created in control vessel 3 during the operating stroke of the aspirator being tested. This arrangement ensures measurement reproducibility, since the initial state of the system is set using a uniform seal fluid level and identical shut-off valve positions, and eliminates the need for electronic sensors and power supplies.An additional advantage is that the volume measurement is not dependent on the instantaneous uneven nature of the air flow during the working stroke of the hand aspirator, since it is determined by the total volume of the displaced sealing fluid.

[0018] In the preferred embodiment, the connecting lines between the nodes are made of glass tubes secured to the support with clamps, which reduces line deformation and increases the geometric stability of the system. The sealing tank 9 can be mounted on a horizontal platform with sides on the mounting panel, and the nozzle 8 for connecting the aspirator can be designed with a universal conical connection for hoses of various diameters. The measuring tank according to clause 2 of the formula is designed as a graduated graduated cylinder, which allows for direct reading of the volume of the drained sealing fluid in milliliters and direct comparison of this volume with the volume of air drawn in by the aspirator in one working stroke.

[0019] The setup operates as follows. Before taking measurements (Fig. 2), check the level of the sealing fluid in the system: open shut-off valve 2 to vent test tank 3 to the atmosphere, ensure that shut-off valves 6 and 7 are open and shut-off valve 4 is closed, and then add sealing fluid to seal tank 9 until a steady overflow occurs into test tank 3. During the top-up process, the displaced air is released into the atmosphere through fitting 1. To improve the repeatability of measurements, it is preferable to use distilled water that has been aged in the test room for at least 24 hours before starting work. After preparing the system, place the aspirator on the work surface and connect it to fitting 8.

[0020] When measuring the volume of air sucked in during a working stroke, the bellows of the aspirator is preliminarily compressed to the stop (Fig. 3), after which shut-off valve 2 is closed and the bellows is released. At this moment, the aspirator takes air from the installation through nozzle 8 (Fig. 4), a vacuum is created in the control tank 3, and the sealing fluid, which is subject to atmospheric pressure in the sealing tank 9, flows through the overflow line into the control tank 3. After the bellows has fully opened, shut-off valve 2 and shut-off valve 4 are sequentially opened, draining the sealing fluid from the control tank 3 through nozzle 5 into the graduated cylinder (Fig. 5). In the preferred embodiment, draining is carried out over a predetermined time interval, for example, over one minute, which reduces the influence of the operator's actions on the reproducibility of the result.The volume of liquid collected in the graduated cylinder is equal to the volume of air sucked in by the aspirator in one working stroke and is determined by the divisions of the graduated cylinder.

[0021] For example, when testing a hand-held aspirator with a nominal stroke volume of 100 cm³, a reading of 100 ml may be obtained at the end of the working stroke and the sealing fluid draining into the graduated cylinder, which corresponds to an actual volume of 100 cm³ of air drawn in during the working stroke. Similarly, when testing an aspirator with a smaller nominal volume, say 50 cm³, a reading close to 50 ml is obtained in the graduated cylinder, and this value is used to assess the actual volume's compliance with the verification procedure. Thus, the same operating principle of the unit allows for servicing various types of hand-held aspirators by selecting the appropriate measuring container and adjusting the initial sealing fluid level.

[0022] After completing the measurements, shut-off valve 4 is closed, the sealing fluid from the graduated cylinder is returned to sealing vessel 9, and the setup can then be used to calibrate the next aspirator, beginning with checking the initial sealing fluid level. During extended breaks in operation, sealing vessel 9 is covered with a lid to reduce evaporation. To ensure consistent metrological characteristics and operational safety, it is advisable to regularly check the tightness of the setup's components, for example, by testing with excess or vacuum pressure within the permissible limits for the components used. The open arrangement of the components on the support and the absence of electronics simplify diagnostics, maintenance, and repair, reducing manufacturing and operating costs compared to electronic flow calibrators and large-scale reference setups.

[0023] The unit can test AM-5M, AM-5P, AM-5E, and AM-0059 bellows aspirators and NP-3M sampling pumps. If devices with similar characteristics become available, they can also be tested on this unit. Flexible PVC tubing of various diameters and adapters between different tubing diameters are used for connection, ensuring convenient and reliable installation. The unit's overall dimensions are 550 x 600 x 150 mm (W x H x D). Its weight is no more than 2 kg (excluding sealing fluid).

[0024] The unit can be operated at ambient temperatures ranging from 10 to 35°C, relative air humidity from 10 to 80% at 25°C, and atmospheric pressure from 84 to 106.7 kPa. The conditions for testing aspirators using the unit must comply with the testing procedures for specific types of aspirators, but must not exceed the specified operating conditions.

[0025] To confirm the repeatability of the volume measurements taken by the aspirators and pumps per working stroke, tests were conducted with various devices (one of each type). The tests consisted of taking a sample 10 times in a row for each device, recording the measurement results. The test results are presented in the table:

[0026] device Measurement, cm3 SKO Permissible error limit according to the description of the measuring instrument type №1 №2 №3 №4 №5 №6 №7 №8 №9 №10 Bellows aspirator AM-5M 97 97 98 97 98 98 97 97 97 97 0,4582 ±5% reduced Bellows aspirator AM-5P 98 98 98 99 99 98 99 99 99 98 0,5 ±5% relative Bellows aspirator AM-5E 99 100 100 99 100 101 100 100 100 100 0,5385 ±5% reduced Sampler pump NP-3M 99 99 99 100 99 99 99 100 100 100 0,4898 ±5% relative Bellows aspirator AM-0059 97 98 98 97 98 98 98 97 97 98 0,4898 ±5% absolute

[0027] The obtained standard deviation (SD) is significantly less than the permissible error limits.

[0028] Test conditions:

[0029] Air temperature: 22.2 °C;

[0030] Air humidity: 52%;

[0031] Atmospheric pressure: 99.8 kPa.

Claims

1. An installation for testing aspirators, comprising a support on which a test tank is secured, connected through a fitting and a shut-off valve to the atmosphere, as well as to a seal tank made open to the atmosphere, a fitting for connecting the aspirator being tested, connected to the test tank, and a drain fitting with a shut-off valve for draining the seal liquid into a measuring tank, the connection between the seal and test tanks forming an overflow line, ensuring the overflow of the seal liquid from the seal tank into the test tank when a vacuum is created in the test tank with a closed shut-off valve connecting the test tank to the atmosphere, during the working stroke of the aspirator being tested.

2. The installation according to paragraph 1, characterized in that the measuring container is made in the form of a graduated measuring cylinder.

3. The installation according to paragraph 1, characterized in that the support is made in the form of a mounting panel fixed to the frame.

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