SU722559A1 - Apparatus for preparing certified gas mixtures - Google Patents

Description

The invention relates to a technique of mixing gases at a certain ratio of components in a mixture, namely, devices for preparing certified gas mixtures, produced by OLE storage and operation in cylinders under pressure and used for calibration, calibration and testing of various gas analyzers that are application in gas, metallurgical, chemical, petrochemical and other fields of industry.

A device for the production of azate mixtures is known, which contains a tank, successively filled with initial components, equipped with elements for connecting a vacuum system to it, sources of mixed gases and a receiving cylinder. Inside the tank are hydrostatic gas scales, the readings of which are recorded when the pre-evacuated tank is filled first with one and then with another of the mixed gases Ij

The disadvantage of such devices is the impossibility of using them to prepare multi-component certified mixtures. The need to have hygrostatic gas scales inside the mixing tank causes the tank to be inefficient, which creates difficulties in its manufacture, limits its volume, the maximum allowable pressure inside it ja causes a poor performance of the device.

A device for preparing gas mixtures is known that implements a weighing method containing precision scales, by means of which the masses of gases that are subsequently dosed into a balloon are measured with a high degree of accuracy by weighing the balloon from the syrup and after entering the components 2j into it.

Such a device makes it possible to obtain both binary and multicomponent gas mixtures certified with an accuracy that meets modern standards.

requirements. However, it is equipped with expensive equipment, produced by single specimens, which requires the use of the labor of highly skilled

metrologist and observance of special harsh hygiene conditions. The process of preparation and certification of mixtures with such a device is laborious and low-grade. On cooking and

certification of one binary mixture in a cylinder with a capacity of 5 l under pressure of 1 MPa takes 5-6 hours, and the preparation of multicomponent certified mixtures is more than 10 hours. Such devices at the current level of their development are not suitable for industrial use.

The closest to the invention according to the principle of operation and technical essence is a device containing a thermostat in which a chamber connected to a vacuum source is placed, and a measuring chamber communicating with it by means of a regulating organ connected to a pressure gauge and source of source gases 3.

To prepare the certified gas mixture, both chambers are evacuated, separated, and first one and then the other needles of the mixed gases are introduced into the measuring chamber, and after each inlet, the pressure in the filled chamber is measured. In this case, measurements are made after the establishment of the thermal equilibrium of the system and the uniform distribution of the components in the mixture.

Release the resulting gas mixture from the measuring chamber to the chamber, connected to a vacuum source, and then to the receiving balance and / or to the atmosphere {if yes & the mixture fell below the norm set for gas cylinders) and repeat this cycle several times, wire t series of isothermal extensions with

by measuring the pressure of the mixture in the chambers after each expansion. Then, after processing the measurement results, the concentration of each of the components in the mixture is determined.

This device allows, using a fairly simple method, to prepare certified both binary and multi-component gas mixtures with a relative error of 0.1-0.3%, satisfying modern requirements, using commercially available measuring equipment.

However, the efficiency of the device is very low, since a large amount of the prepared mixture, according to the process technology, has to be released into the atmosphere. Due to the imperfection of its design, it has a low productivity, which is directly dependent on the volume of the chambers included in its composition. However, an increase in volumes leads to an increase in the time spent on establishing the thermal equilibrium of the system after each expansion and on evacuating the chamber before the next expansion.

The purpose of the invention is to increase the efficiency and productivity of

To achieve this goal, a device for preparing certified gas mixtures contains a chamber connected to a vacuum source placed in a thermostat and a measuring chamber connected to it by means of a regulating body connected to a manometre is equipped with a storage chamber communicating with the measuring chamber by means of an axial chamber. openings, equipped with a shut-off valve, at the floor, the storage tank is connected to a vacuum source and provided with a mixing body.

The mixing body is made in the form of a fan and is equipped with a discharge pipe installed coaxially with the blower, made as two telescopically connected pipes, one of which is coaxially installed in the axial hole, connected to the shut-off valve and filled with windows located in its axial opening. upper part

FIG. 1 shows a schematic diagram of the device; in fig. 2 - a general view of the device without a thermostat, a longitudinal section.

Claims (2)

The device contains the measuring chamber 1, the camera 2 communicating by means of the regulator - the valve 3. The measuring chamber 1 is equipped with a storage capacity 4 and is connected to it, axially 5, in its common housing, with a valve 6, which is located inside the measuring chamber 1 and equipped with a mechanism 7 peremetseni shutter 8, derived from the Kopiyca 9, subject to the conditions of tightness. Measuring chamber 1 and accumulative capacity 4 are in the form of coaxially disposed cylinders, and chamber 2 suppresses an annular channel that is large in the body of the body 9. In order to reduce the mixture losses, cameras 1 and 2, designed to perform isothermal expansions, separate the minimum allowable the volumes calculated from the condition of ensuring a sufficient number and accuracy of measurements necessary for the certification of mixtures within the required error. In construction, this ratio is 1.467О74. The volume of the measuring chamber is 0.0001 m. The capacity of the device depends on the volume of the cumulative tank 4 used for preparing the mixture and filling the receiving cylinders 10 under pressure. Therefore, the storage tank 4 is made of the maximum possible volume O, O07 m, limited by the rational dimensions of the thermostat 11. Inside the storage tank 4, there is a mixing body 12, filled in the form of a fan 13, fixed on the base of the body 9 of the fan 13, equipped with an injection pipe 14 containing two bodies : a copy connected between the nozzle 15 and 1 One of the nozzles 15 is fixedly mounted on the casing 17 of the fan 13, and the other 16 is placed with a gap 18 in the axial bore 5 and is sariirno connected by means of cone 19 with the shutter 8 of the shut-off valve 6, in the casing 17 of the fan 13 and in the nozzle 1 there are holes 2O, 21 for the passage of gases. The fan 13 is connected by magnetic coupling 22 with an electrolyte 23. The device is equipped with a piping system with shut-off valves 2430 that switch the circuit elements. Chamber 2, which is connected to the atmosphere, is connected to a vacuum source 31, which contains a vacuum pump 32, a trap 33, and a vacuum gauge 34, a measuring chamber 1 is connected by means of a membrane cutter 35 and a gas oil discharger 36, and a pressure balance gauge 37, and a storage tank 4 - with a receiving cylinder 10 and a nocToeHf plant with a desiccant 38 - with a source of source gases (not indicated in the drawing). The device contains a thermometer 39 to the source gas supply line 4O. Prepare certified gas mixtures as follows. For the entire period of operation of the device include a thermostat 11, which maintains in all parts of the device in the thermostat 11, the required temperature measured by the thermometer 39. The shut-off valve 6 is opened and all valves, except 29, start the engine 23 of the stirring member 12 and vacuum - The pump 32 evacuates the entire system through the trap 33, controls the degree of vacuum with the vacuum meter 34. After the required vacuum has been reached, the vacuum pump 32 is turned off and having separated the valves 3, 1 and 2 by means of valves 3, and closing the valves 25, 26, 28 and 30, and 40 supplying initial gases and desiccant 38 to accumulative tank 4 and measuring chamber 1 connected to it, first the first and then the second component of the mixture, control the pressure of the injected gases by means of a piston-type manometer 37 and use the separator 36 of oil and gas diaphragm and cutoff 35 carried out until the controlled pressure of both the zl of the first component and the mixture reaches levels predetermined (approximately) in accordance with the required characteristics of the mixture and taking into account the capabilities of the device. After the inlet of the first gas, the valve 27 is closed and after the establishment of thermal equilibrium in the system, the pressure of the inlet gas is finally measured. Further, with the valves 24, 25 and 26 open, the source gas supply line 4O is evacuated, then the vacuum pump 32 is turned off, the valves 25, 26 are closed and, the valve 27 is opened is introduced into the storage tank 4 and the measuring chamber 1 communicated with it 1 blend components. After the mixture has reached the required pressure, controlled by a piston-type manometer 37, the valve 27 is closed and wait for some time until the thermal equilibrium of the system is established and the components are uniformly distributed in the Mixture, achieved with the mixing organ. When rotating from the electric motor 23, the fan 13 sucks the gas mixture from the storage tank 4 through the windows 20 under the casing 17 of the fan 13, pumps it under pressure into the nozzles 15, 16 and delivers through the windows 21 in the direction set by the guide cone 19 chamber 1, from which the mixture returns to the storage tank 4 through the gap 18 between the wall of the opening 5 and the nozzle 16. The circulation and the exchange of gases between the tank and the chamber achieved during this process, due to the formation of directional flows, effectively mix the components s and obtaining a homogeneous mixture in the tank 4 and the chamber 1 for 15 minutes After establishing the thermal equilibrium of the system and obtaining a homogeneous mixture, the electric motor 23 switches on the pressure of the prepared mixture with a piston-type manometer 37, and then the shutter 8 of the shut-off valve 6 using the mezanism 7 moves seals the axial orifice 5, connecting the chamber 1 Next, open valve 3 and push the prepared gas mixture from chamber 1 into chamber 2, and then closing valve 3 and opening 29, into the atmosphere, after which chamber 2 is evacuated. Repeat this cycle 4-8 times, a series of isothermal expansions are carried out with the mixture pressure measured in the reported chambers 1 and 2 after each expansion and subsequent establishment of thermal equilibrium. The valve 6 and valve 3 are shut off and mounted in the device so that their operation does not change the volumes of the chambers 1, 2 filled with the gas mixture and capacity 4 and does not affect the qualification accuracy. After processing the measurement results, the concentration of the components in the mixture is determined. The prepared and certified gas mixture opens the AO valve into the receiving cylinder Y. To obtain a multi-component, certified gas mixture, all operations are carried out according to the above method, taking the previously obtained certified mixture stored in the 1 x tank of 4, for the first of the original components. The presence in the device for preparing certified gas mixtures equipped with a mixing body of an accumulation tank connected to the metering chamber with an axial bore having a shut-off valve allows reducing the volumes of the chambers designed for carrying out isothermal expansions to MHHmviyMa mixture at the same pressure. Due to this, the proportion of the prepared mixture released into the atmosphere after each expansion is significantly reduced, and the amount of the mixture discharged for use from the storage tank, where this mixture is kept at its initial pressure, into the receiving cylinders under pressure increases. The efficiency of the device increases 1.6 times and more than 28 risks reduce the loss of expensive source gases. The productivity of the device is increased due to an increase in the amount of the mixture used for use in receiving cylinders, a decrease in the volume of the chambers used for this and a reduction in the time to establish thermal equilibrium and the time of evacuation after each expansion. The performance of the proposed device is 1.7 times higher than that of the known. It has smaller than known dimensions (approximately 1.4 times). The economic effect from the use of the proposed technical solution is more than 11 thousand rubles. per year for one set of equipment. Claim 1. Device for: preparing certified gas mixtures, comprising a Thermostat in which a chamber connected to a vacuum source is located and a measuring chamber connected to it by means of a regulator, connected to a manometer and source of source gases, characterized in that In order to increase the efficiency and productivity of the device, it is equipped with a storage capacity, communicating with the metering chamber through an axial bore, equipped with a shut-off valve, oedinena to a vacuum source and provided with an agitator body. 2. The device according to claim 1, characterized in that the mixing body is made in the form of a fan and is provided with a pressure pipe installed coaxially with the fan, made in the form of two telescopically interconnected connections, one of which is coaxially mounted in an axial hole, connected to shut-off valve and is made with windows located IT in its upper part. 9J Sources of information taken into account in the examination of 1, Aiken A. Course of chemical fnznki; M ,; 1935, p. 90. 2. Abstract collection of Kisloroan industry. M., 1977, p. 1b-21. a.XCtiem.Pbs .. 23 № 3, 5О9-513, 1955 (prototype).