RU64958U1 - DEVICE FOR DETERMINING GAS DISCHARGE PARAMETERS FROM FILLED INSULTS OF CASTING FORMS - Google Patents

Abstract

The utility model relates to the field of foundry and is intended to determine the parameters of gas evolution from cast molds with the aim of predicting the gas contamination of casting departments of foundries. The device comprises an upper half-mold (1) with a cavity (3) for pouring with molten metal, a lower half-mold, which includes a sleeve (6) with a heat-insulating cylinder (7) and a test sample (8) of the mixture and a hermetically sealed cover (10) with the formation free cavity (13). The device provides a source (14) of carrier gas, connected by a communication line (16) with a sensor (17) of its flow rate through the hole (11) to a free cavity (3). The latter through the hole (12) is connected by a communication line (18) to the atmosphere through a sensor (19) for determining the concentrations of toxic components. According to a utility model, the device is additionally equipped with a system (21) for processing experimental data, a sensor (23) for determining the humidity of gases, a block (24) of sensors (25-25 '') of temperature distributed in the volume of the test sample (8), while there is a free cavity (3) is connected directly to the atmosphere through a switching device (27), and a humidity sensor (23) is installed in the communication line (18). Moreover, all sensors (17, 19, 23 and 25-25 '') in the device are connected to the system (21) for processing experimental data through a plateau (22) for data collection, and the heat-insulating cylinder (7) is made of ceramic with an internal closed cavity (28 ) filled with thermal insulation material. The device also provides a number of options for its execution. 1 n.p.f., 4 ill.

Description

The utility model relates to the field of foundry and is intended to determine the parameters of gas evolution from cast molds in order to predict the gas contamination of casting departments of foundries under various production conditions.

A known design of a speed device for determining the rate of gas evolution from molding and core mixtures, in which there is an upper half-form and a lower half-form, which includes a sleeve with a heat-insulating cylinder and a sample of the test mixture. The unit is equipped with a calibrated washer and a V-shaped pressure gauge [1].

A disadvantage of the known device is that for measuring the gas evolution rates of undiluted shaped gases from the studied mixtures, a diaphragm calibrated by air is used. At the same time, the chemical composition, humidity and viscosity of undiluted shaped gases released from the test mixtures differ significantly from the properties of air, which introduces a significant error in the measurement of gas release rates from metal-filled molding and core mixtures.

In addition, the design does not allow taking into account the experimental errors associated with the difference in the conditions of thermal decomposition of mixtures, as well as gas filtration at the boundary of the mixture sample and the lower half-mold and inside the mixture under study.

A known design of a device for determining the rate of gas evolution from molding and core mixtures, adopted as a prototype, consisting of an upper mold half, which includes a flask with a mixture, as well as a cavity for pouring molten metal, and a lower mold half, including a metal mold, a sleeve with a heat-insulating cylinder and a test sample. The device also includes a cover with two holes, a carrier gas source for purging the free cavity between the sample and the cover, as well as a sampler for determining the composition of the gas mixture associated with the atmosphere, and the base [2].

The disadvantage of the prototype device is that its design does not allow to obtain the necessary amount of information about the processes of gas evolution from the studied samples filled with molten metal in casting molds, as well as the complexity of research. In addition, the known device does not have sufficient information and accuracy in obtaining experimental data and their mathematical processing, since it does not provide for computerization during research.

The technical problem to which the utility model is directed is to increase the information content of research and the accuracy of measuring the gas evolution from the studied samples of cast molds when organizing the automatic processing of experimental data and calculating gas evolution from the samples.

An additional technical task is the ability to reduce the complexity and material consumption of research.

The stated technical problem is solved in that a device for determining gas evolution from molten molds filled with liquid metal, comprising an upper half-mold with a cavity for pouring liquid metal and a lower half-mold, which includes a sleeve with a heat-insulating cylinder and a test sample fixed with a mesh, a hermetically sealed lid with two holes, and a free cavity formed between the test sample of the mixture and the sleeve cover, a carrier gas source with an adjustable element ntom connected via a carrier gas flow sensor and one of the holes in the lid to a free space, which through another hole in the lid is connected with the atmosphere through the sensor determining the concentration of toxic components, and a base, according to the utility model, the apparatus further provided with a system

processing of experimental data and connected to it together with a carrier gas flow sensor through a data collection plate, a gas humidity detection sensor and a block of temperature sensors distributed in the volume of the sample to be studied, installed in a third hole made in the sleeve cover additionally, while the free cavity is additionally directly connected to atmosphere using a switching device, and a gas humidity detection sensor is installed in the communication line between the free cavity and the atmosphere between the openings Thieme in the lid and the switching device, the insulating cylinder is provided with a ceramic inner closed annular cavity filled with insulation material.

The technical problem is solved in that, according to a utility model, the upper half-mold is made disposable in the form of a flask filled with molding sand.

The technical problem is also solved by the fact that the device is additionally equipped with a melting furnace with a graphite crucible for melting metal, while the melting furnace is equipped with a tube with a graphite tip and a temperature sensor and is mounted on the upper half-mold, and the temperature sensor is connected to the data processing system via a data acquisition plateau.

In a particular case, according to a utility model for solving an additional problem, namely, the possibility of reducing the complexity and material consumption, the upper half-mold is made of reusable ceramic refractory material.

The technical problem is also solved by the fact that in the particular case according to the utility model, the device is additionally equipped with a flow sensor of undiluted shaped gases mounted in the communication line of the free cavity with the atmosphere between the gas moisture detection sensor and the switching device.

The solution of the technical problem is achieved due to the fact that the device is additionally equipped with an experimental data processing system and a number of sensors connected to it together with a carrier gas flow sensor, namely, a gas humidity detection sensor and a block of temperature sensors distributed over the volume of the test sample, and a particular case is a flow sensor of undiluted shaped gases, a temperature sensor of molten metal in a melting furnace. At the same time, it becomes possible to capture signals from all sensors and process them in express mode using a computer with great accuracy.

In addition, the structural design of the insulating cylinder liner with an inner closed annular cavity filled

heat-insulating material allows to prevent the heating of the side surfaces of the test mixture sample, and, therefore, to more reliably estimate the rate of gas evolution from the test sample as a result of thermal destruction (pyrolysis) due to heating of the sample through the contact surface "liquid metal - test mixture sample".

An additional technical problem, namely, the possibility of reducing the complexity and material intensity, is solved by the fact that in the particular case the upper half-mold is made reusable, allowing to save working time, as well as materials.

The essence of the utility model is illustrated by drawings, where figure 1 shows a diagram of the proposed device; figure 2 is the same in a particular case when used in the composition of the device of the melting furnace; figure 3. a diagram of a device using a reusable upper mold with a melting furnace in a particular case; figure 4 is a diagram of a device for determining the parameters of gas in the case of undiluted shaped gases.

The following notation is used in the drawings: δ — geometric dimension (thickness) of the cavity for pouring with liquid metal, simulating the predominant wall thickness of the casting; h is the geometric size of the test mixture sample, simulating the prevailing wall thickness of the mold; Wfg - rate of formation gas formation from

of the test sample mixture due to the processes of thermal destruction (pyrolysis) that occur when pouring the sample with liquid metal.

In addition, the arrows show the direction of motion of both the carrier gas and the shaped gases.

A device for determining the parameters of gas evolution from molded metal samples of casting molds (see Fig. 1) contains an upper half-mold 1, in which a riser 2 is provided for pouring a cavity 3 with liquid metal between the upper half-mold 1 and the lower half-mold (not indicated in the drawing), and also vents 4 for removing air from the cavity 3. The upper half-mold 1 in the form of a flask 5 with the mixture and with the cavity 3 is fixed together with the lower. The lower half-mold includes a sleeve 6 with a heat-insulating cylinder 7 and a test sample 8 of the mixture fixed in a sleeve 6 with a mesh 9, a hermetically sealed cover 10 with two holes 11 and 12, and a free cavity 13 formed between the test sample 8 of the mixture and the cover 10 sleeves 6. The device also includes a carrier gas source 14 with a regulating element 15 in the form of, for example, a valve connected by a communication line 16 through a carrier gas flow sensor 17 and one of the holes in the cover 10, namely, the hole 11, to free bands ty 13. The latter through another hole 12 in the cover 10 is connected by a communication line 18 with the atmosphere through the concentration sensor 19

toxic components. The entire design of the device is based on the base 20. According to a useful model, the device is additionally equipped with a system 21 for processing experimental data in the form of a computer, as well as connected to it together with the sensor 17 of the carrier gas flow through the plateau 22 of the data collection by the sensor 23 for determining the humidity of gases and the block 24 of the sensors 25, 25 ', 25' ', 25' '' of temperature in the form of a set of thermocouples and thermistors. Block 24 of the temperature sensors is installed in the third hole 26, additionally made in the cover 10 of the sleeve 6.

Temperature sensors 25-25 '' 'are distributed in the volume of the test sample 8 of the mixture. In this case, the free cavity 13 is additionally connected directly with the atmosphere using a switching device 27 in the form of, for example, a three-way valve, and a gas humidity detection sensor 23 is installed in the connection line 18 of the free cavity 13 with the atmosphere between the hole 12 in the cover 10 and the switching device 27. Moreover, the heat-insulating cylinder 7 is made of ceramic refractory with an inner annular cavity 28 filled with heat-insulating material, for example, kaolin wool. It is envisaged that the inner annular cavity 28 is closed by a ceramic refractory cap 29.

The size of the free cavity 13 in height is determined by the distance

between the test sample 8 of the mixture, which is made in the heat-insulating cylinder 7, and the cover 10 and can be set using a ceramic stand 30.

In the device in a particular case, the upper half-mold 1 can be made, as a special case, disposable in the form of a flask 5, filled with molding sand (see figure 1).

In addition, the device may be further provided with a melting furnace 31 and a refractory lid 32 with a graphite crucible 33 for melting metal. In this case, the melting furnace 31 is provided with a tube 34 with a graphite tip 35 and a temperature sensor 36 mounted inside the tube 34 for measuring the temperature of the molten metal. A tube 34 with a fixed graphite tip 35 serves to supply molten metal to the upper half-mold 1 through the gate 38, which is connected to the riser 2 of the upper half-mold 1. In this case, the centering pins 39 serve to fix the melting furnace 31 on the upper half-mold 1, and the temperature sensor 36 a thermocouple is connected to the experimental data processing system 21 through the data collection plateau 22 (see FIGS. 2 and 3).

In the device in the particular case of the upper half-mold 1 can be made reusable of ceramic refractory material (figure 2 and 3). In this case, the upper half-mold 1 and the lower are fixed with

case ring 5 '.

In the main case and in each of the particular cases, the device can be additionally equipped with a sensor 40 for the flow of undiluted shaped gases installed in the communication line 18 of the free cavity 13 with the atmosphere between the gas humidity detection sensor 23 and the switching device 27 (see Fig. 4).

A device for determining the parameters of gas evolution from the cast molds works as follows.

After filling the cavity 3 of the upper mold half 1 with liquid metal through the casting tower 2, air is displaced through the vents 4 into the atmosphere (see figure 1).

Under the influence of high temperatures in the test sample 8, made in a heat-insulating ceramic cylinder 7, placed in the sleeve 6, the processes of gas formation, filtration and release of molded gases in the free cavity 13 between the grid 9 and the cover 10, in which the toxic components of the molded gases are mixed with gas -carrier (for example, argon) coming from the carrier gas source 14 via the communication line 16 through the regulating element 15 in the form of a valve and the hole 11 in the cover 10. Moreover, the carrier gas flow sensor 17 ingly on the selected flow rate of the carrier gas, captures the carrier gas flow rate values

which are installed with the help of the regulating element 15. Then, the carrier gas mixture formed in the free cavity 13 with the shaped gases released from the mixture sample 8 passes through the hole 12 in the lid 10 via the communication line 18 through the switching device 27 directly into the atmosphere, or through the sensor 19 determines the concentration of the i-th toxic gas at various points in time. Installed in the communication line 18, a sensor 23 for detecting gas humidity detects moisture values of a mixture of carrier gas and formed gases.

Knowing the carrier gas flow rate Wgn and the concentration of toxic gas Ki in the gas mixture, we can calculate the mass velocity Wi of the emission of the ith toxic gas from sample 8 of the mixture using the expression

Wi = 0.001 · Wgn · Ki, mg / min,

where WGN is the velocity of the carrier gas, l / min; Ki is the concentration of the toxic component in the gas mixture, mg / m ³ .

In addition, during the study, the device allows you to record the temperature change both at the boundary "liquid metal - sample mixture" and at the border "sample mixture - free cavity", and at various points in the volume of the sample 8 mixture through block 24 of the corresponding temperature sensors, for example, 25 and 25 '; 25 '' and 25 '' 'installed in the hole 26 of the cover 10.

The signals from the sensors 17, 23, 19, and 25-25 ″ are fed to the experimental data processing system 21 in the form of a computer via the data collection plate 22, are recorded in the experimental data base file, and then automatically processed according to the program.

The ceramic heat-insulating cylinder 7 used in the sleeve 6, made with a ceramic lid 29 and with an inner closed annular cavity 28 filled with heat-insulating material, in particular asbestos chips or kaolin wool, can prevent, together with the ceramic stand 30, heating of the side surface of the sample 8 of the mixture with side of the sleeve 6. The latter perceives the heat of the elements of the upper half-mold 1.

Organized in this way, the operation of the device allows you to more accurately and informatively determine the parameters of gas evolution from molten molds flooded with liquid metal, as automatic recording and processing of signals from sensors in express mode is provided.

The upper half-mold 1, as a special case, can be made disposable in the form of a flask 5, filled with a molding sand (see Fig. 1), which makes it easier to simulate the thermal regime of a molded mold filled with liquid metal, especially in workshop conditions.

In the particular case when the device is additionally equipped

a melting furnace 31 with a graphite crucible 33, a tube 34 with a graphite tip 35 mounted on the tube 34 together with the temperature sensor 36 and closing and opening the hole for supplying liquid metal to the upper mold 1 through the gate 38. In this case, the filling of the upper mold 1 with liquid metal 37 the required temperature occurs almost without loss. The signals from the temperature sensor 36 are also sent through the data collection plateau 22 to the experimental data processing system 21 and are recorded in the experimental data base file along with the signals from other sensors. That is, in this case, in addition to increasing information content, it is simultaneously possible to increase the accuracy of studies of the process of gas evolution from samples 8 of the mixture (see figure 2 and 3).

According to the utility model, in the particular case when the upper half-mold 1 can be made of reusable ceramic refractory material (see Fig. 3), it becomes possible to further reduce the laboriousness when conducting research, since with this approach one set of the upper half-mold 1 is used repeatedly ongoing research. This reduces the overall material consumption of the device. In this case, the upper half-mold 1 can be made, for example, of fireclay bricks or fireclay-fiber boards. In laboratory conditions, such a device will be preferable. With additional supply of the device

would be preferable. With an additional supply of the device with a sensor 40 for the flow of undiluted shaped gases (see Fig. 4), this design allows studies to determine the parameters of gas evolution without using a carrier gas. At the same time, in the communication line 16, with the help of the regulating element 15, the carrier gas supply from the source 14 to the free cavity 13 is blocked, and the carrier gas flow sensor 17 is disconnected from the experimental data processing system 21. Such a scheme for conducting studies to determine the parameters of gas evolution is expedient both for predicting the gas contamination of industrial premises of foundries [3] and environmental pollution by industrial emissions of foundries [4], and for assessing the likelihood of gas defects in castings. The parameters of gas evolution are calculated by a known method [5].

Thus, the proposed utility model generally increases the information content of the gas evolution research process and the accuracy of measuring the gas evolution parameters from the studied samples of cast molds, moreover, in automatic processing of experimental data and calculation of gas evolution from the samples.

Information sources

1. A.S. USSR No. 193131, M class. B22C 9/00, publ. 1967. (analog)

2. RF patent №2247624 ,, 7 IPC V22C 9/00, publ. 2005 (prototype).

3. Pogosbekyan Yu.M., Papovyan M.N., Uspensky M.D. Gas evolution in foundries and forecasting gas contamination of industrial premises // News of Universities. Ferrous metallurgy, No. 1, 2005. S. 52-56.

4. Pogosbekyan Yu.M. On the issue of dispersion of industrial emissions of metallurgical plants in the environment // News of Universities. Ferrous metallurgy No. 3, 1992. P.82-85.

5. Medvedev Y.I., Pogosbekyan Yu.M. Determination of the rate of gas evolution from foundry molds. Izvestiya Vuzov. Ferrous metallurgy, No. 7. 1977. S.152-154.

Claims (5)

1. A device for determining the parameters of gas evolution from molten molds filled with liquid metal, containing an upper half-mold with a cavity for pouring liquid metal, a lower half-mold, which includes a sleeve with a heat-insulating cylinder and a test sample mixture fixed by a mesh, a hermetically sealed lid with two holes and a free cavity formed between the test sample of the mixture and the sleeve cover, a carrier gas source with a control element connected through a gas flow sensor -carrier and one of the openings in the lid to a free cavity, which through another opening in the lid is connected to the atmosphere through a sensor for determining the concentrations of toxic components, and a base, characterized in that the device is additionally equipped with an experimental data processing system and connected to it together with a flow sensor carrier gas through the data collection plateau with a gas humidity detection sensor and a block of temperature sensors distributed in the volume of the sample under study, installed in an additional it is located in the sleeve cover of the third hole, while the free cavity is additionally connected directly to the atmosphere using a switching device, and a gas humidity detection sensor is installed in the communication line between the free cavity and the atmosphere between the hole in the cover and the switching device, the heat-insulating cylinder made of ceramic with an inner closed annular cavity filled with insulating material. 2. The device according to claim 1, characterized in that the upper half-mold is made disposable in the form of a flask filled with molding sand. 3. The device according to claim 1, characterized in that the device is additionally equipped with a melting furnace with a graphite crucible for melting metal, while the melting furnace is equipped with a tube with a graphite tip and a temperature sensor and is mounted on the upper half-mold, and the temperature sensor is connected to the data processing system . 4. The device according to claim 1, characterized in that the upper half-mold is made of reusable ceramic refractory material. 5. The device according to claim 1 or 3, characterized in that the device is additionally equipped with a flow sensor undiluted shaped gases mounted in the communication line of the free cavity with the atmosphere between the sensor for determining gas humidity and a switching device.