SU1301854A1 - Control system for chemical and heat treatment of articles in furnace - Google Patents

Abstract

The invention relates to devices for controlling the composition of the gas in a furnace atmosphere during chemical-thermal treatment of products. The purpose of the invention is to improve the quality of chemical heat treatment. The invention consists in the fact that during processing the temperature of the gas in the furnace is measured by the sensor 13 6, the humidity of the gas by the sensor 7, the pressure by the sensor B, the composition of the gases by the sensor 15 and the number of parts entering the furnace by the sensor 5. These sensors are connected to the inputs of the control computing device (CCD) 9. Depending on the readings of the sensors CCD 9 changes the ratio between the gas and the air coming through the endothermic generator 1 and the mixer 2 into the furnace 4, with an actuator 12 installed on the pipe ode .vozduha supply 13 to the generator 1. The CCT 9 also controls, with the help of valves 10 and 11, the composition and the amount of gases coming from the cash register of gases 14 (tank) to the mixer 2, which makes it possible to regulate the composition of the atmosphere in the furnace 4. 1 sludge. CL iZ 1110 / IV / e about o 00 about 00 CL

Description

25

113018

The invention relates to chemical treatment (HTO), and more specifically to devices for controlling the remaining gas of a furnace atmosphere, and can be used, for example, in engineering, gas and oil industry.

The aim of the invention is to improve the quality of chemical-thermal processing. ABOUT

1 sketch shows the proposed system.

The CTO system of products contains an endothermic generator 1, connected through a mixer 2: with a conduit З to -5 oven 4. Sensor} :: 5-8, respectively, of parts counting, gas temperature, gas: gas, gas pressure are connected to the control computer the device (CWC) 9. The CCD 9 is connected through valves 10 and 11 (actuators) to the mixer 2, and through the actuator 12 to the pipe 13 supplying air to the endothermic generator 1.

The cash register 14 of the gases (tank) through the valves 10,11 is connected to the mixer 2. The XTO system of the products also contains a sensor of composition a30Bj connected to the CCT 9.

The system works as follows.

The endogenerator 1 enters the pipeline gas and air. At the same time, the air using the executive mechanism 35 in the pipeline 13 is controlled by the CCS 9, carrying out coarse control of the carbon potential according to the information about the humidity sensor 7 taking into account the gas temperature measured by the sensor 6,

Endogas through the pipeline 3 enters the furnace. On pipeline 3, there is a mixer 2 mounted, mixing endogas 45 with the necessary precise addition of a specific gas from the cash register of 14 gases. The control of the supply of additional gases (precise adjustment of the atmosphere is carried out by valves 10 and Q 11 (actuators: mechanisms) of the CCS 9, Sensors 15.6.8 and 5, respectively, of the composition of gases, temperature, pressure and counting of parts are installed directly in the furnace, are connected with the input of the HCD 9, which processes the readings and maintains the optimal mode of operation of the system according to the required parameters.

42

The system has the first closed loop (external) control - sensors 6 and 7, a control computing device (CCD) 9, an actuator 12, pipeline 13, a main source of gases (endogenous generator) 1, a mixer 2, pipeline 3, a furnace 4, as well as the second closed adjustment (internal) KON.TUR control - sensors 5-7, SWD 9, valves 10 and 11 with a corrective cash register 14 gases, mixer 2, pipeline 3, furnace 4.

The design features of the system for controlling the heat and chemical treatment of products: the presence of two control and regulation loops, sensors, actuators: 5 anisms that perform the functions of coarse control of the furnace atmosphere (carbon control) and accurate adjustment by means of the cash register of gases are essential and necessary ., because at the expense of these features and devices, precise (adjustment, control) of the furnace atmosphere in the furnace itself is required, and the system invariance is guaranteed I am disturbed by m.

Constructive implementation of the system and communications due to the technical ability to supply at any time interval exactly the calculated amount of an additive of a well-defined gas, which is not even in the main sources of gases, provides the necessary atmosphere of the furnace and the quality output of products about

The use of counting and pressure sensors in conjunction with a gas casing and a mixer connected directly to the endogas pipeline in front of the furnace will significantly improve the quality of the gas and its composition, including those gases that, at the output of the generator, for a number of process aids: there are insufficient quantities or none at all.

With the aid of CCS 9, it is possible to introduce various constants into this multifaceted system of automatic control, for example, the presence of one or another alloying element in the parts being processed, to provide control, practically, by any laws.

313018

The presence of separate closed control loops will increase the accuracy and quality of control.

Upon receipt of information from the furnace sensors in the CWS 9, according to the algorithm embedded in it, it calculates the amount of addition of that or ionic gas, which is proportional to the number and area of the products being processed, taking into account the JO temperature and current pressures of the furnace and at the cash desk for each gas . The CCT, using its own time counter, controls the duration of the transfer of gases to the mixer from the cash register. Taking into account, 5 that the two circuits are regulated

NIN, THEN the first, rough contour (external) works by the following equation:

t dt

+ X KY,

25

input for example availability

from sensor 7;

an output that determines control of the actuator 12; constant time for example

endogenerator

coefficient depending on the co-ZO gain factor in the circuit.

more accurate adjustment of the carbon potential takes into account the coefficient of gas 1:

cash outflow rate

4.t- from 9 to K

doping factor, 35 11 (actuators) for temperature sensor 6 is used and entered based on its readings and steel alloying correction factor (material) corrections (from the table) from the information control console of the CCD 9. In system 40, it is possible to programmatically control in a wide range of composition of the furnace atmosphere, including during the heat treatment cycle.

The composition of the product (parts), their area and quantity influence the composition of the gas in the furnace itself. To account for this, an account sensor 5 is installed in the HTO system, and there is an area of products in the memory of the CCT 9. This technical solution is illustrated by the following dependencies.

The second circuit (corrected) works according to the equations

55

- heat engineering constant, for example, for CO at t it is equal to 1.171; R - gas constant, T, 273.15 + t (t - temperatures

in the oven);

Р, - pressure in the furnace, PQ - pressure in the i-th cylinder, specific volume of the 1st gas in the outlet section

V V (- “-) - 1 ° Р, 1 kg J

Checkout

 t

n-SnM.

where

Etc

R

- volume second consumption of the 1st gas

where - the total area of processed products

- the number of products of each name,

- the area of one product of each name.

-k; c; t r p v. , but . B- gm i,

Oi, 1 1 L J

de vj - the specific value of the volume

gas i-ro, adjusted to the current values of temperature and exposure time for the corresponding gas, the specific value of the volume depletion of the i-ro gas constituting the furnace atmosphere, at certain constant values of t and c,

i th; , B;

with; - constant coefficients for i-ro gas,

t is the current temperature value;

t - the duration of the products in the furnace

V; V:

s, v

arr KoHip

M

where V is the volume depletion by i-th

gas;

conf factor configuration details.

Algorithms (equations) for determining the opening time of the valves 10 and

1st gas:

cash outflow rate

11 (actuators) for

4.t- (actuators)

where k

 11 (actuators) for

- heat engineering constant, for example, for CO at t it is equal to 1.171; R is gas constant, T, 273.15 + t (t is temperature

in the oven);

R, is the pressure in the furnace, PQ is the pressure in the i-th cylinder, the specific volume of the 1st gas in the outlet section

V V (- “-) - 1 ° Р, 1 kg J

U „:

Etc

R

- volume second consumption of the 1st gas

V -

R.V.p. LC J

where F is the area of the output section,

p is the density of i-ro gas. Finally, there is a time during which; the i-th valve must be open,

v; g -,

™ --- C

V. LCJ

v; R

using UBU 9 for the second circuit. Values of variables and coefficients assigned can be found in technical specifications, GOSTs and other gas manuals

) 0

1% chromium and 1% manganese. This addition is carried out at the expense of the internal circuit, and the entire cycle of XTO COj is stabilized at a level of 0.43% CO due to an external 0.4% C0 and internal 0.03% COj.

Moreover, the gas pressure in the furnace 50 mm in one ton.

A batch of blanks is visually inspected, hardness tested and the amount of carbon (C) determined by chemical analysis. No oxidation, hardness

In the absence of the proposed system, 5 product surfaces fluctuate in

We, when sintering a product made by powder metallurgy from a mixture with an iron powder PZHZ, together with the necessary hardness HB 110-120, form hardness of the order HB 120-190. Such a drop in hardness is observed even on a single product. At the same time, the carbon content exceeds the nominal value by a factor of 2-3 and reaches 0.38%. Since this sintering of the products requires further mechanical and other processing in accordance with the technology, the problem arises of using a special tool.

In this case, the loss of excessive carbon production or oxidation is 30%.

Example. XTO conducts products (parts) with the use of the proposed system, made of: the following composition of the material,%: chromium 1, manganese 1; carbon 0.03; silicon 0.1, sulfur 0.02; phosphorus 0.02; iron else.

The composition of the atmospheric atmosphere,%: CO 18 22, H 28-30, CO, 0.4, CH, 0.3, 0 0.2, which is maintained (stabilized) by the first closed (external circuit. The details pass for two hours the processing cycle, but since the composition of the material of the parts contains alloying elements, for the normal and high-quality flow of HTO, from the first two minutes they introduce from the additional volume CH (the second corrective closed loop).

In order to maintain an optimal furnace area, an additional volume of CHi is introduced to the value of CO-, a wound of 0.43%. In this case, the main effect in the increase in CO is

the guiding elements of the material products.

1% chromium and 1% manganese. This addition is carried out at the expense of the internal circuit, and the entire cycle of XTO COj is stabilized at a level of 0.43% CO due to an external 0.4% C0 and internal 0.03% COj.

Moreover, the gas pressure in the furnace 50 mm in one ton.

A batch of blanks is visually inspected, hardness tested and the amount of carbon (C) determined by chemical analysis. No oxidation, hardness

product surfaces vary in the nominal process limits: HB 110-120, and carbon content is in the order of 0.12-0.14%.

The presence of a plurality of the closed system of automatic regulation, allowing ush, to provide the furnace with the necessary atmosphere, to significantly reduce the discharge of XTO, the CCT creates centralized control and increases the speed of the entire system.

thirty

Formulas

isoretreni

five

P

 from

five

0

The control system for the chemical heat treatment of products in the furnace, containing an endogenerator, and connecting gas and air supply pipelines connected to it, an actuator with a regulator changing the ratio of gas and air flow rates to the endogenerator, temperature sensor, humidity and gas composition, tanks for process gases, a control computing device, a mixer and actuators with control valves on the supply lines of gas components from tanks to the mixer installed between the endo-generator and the furnace, and the outputs of the D-sensor of gas components, temperature sensor and power sensor are connected to the inputs of the controlling computing device, the outputs of which are connected to the actuators on the gas supply lines to the mixer and to the regulator of the gas ratio change and the air supplied to the endogenerator, distinguishing from the fact that, with the aim of increasing 713018548

Neither does the quality of the chemical-thermal treatment of the pressure sensors and the counting of the details of the bots, it is equipped with a pressure sensor connected to the input of the control unit and to the counting sensor of the parts, device.

Claims (1)

Claim A control system for the chemical-thermal treatment of products in a furnace containing an endogenerator and natural gas and air supply pipelines connected to it, an actuator with a regulating body for changing the ratio of gas and air flows supplied to the endo 4Q heatsink, temperature, humidity and gas composition sensor, capacity for process gases, control computing device, mixer and actuators with control valves on the supply lines of gas components from the tanks to the mixer, installed between the endogenerator and the furnace, and the outputs of the gas component sensors, temperature and humidity sensors are connected to the inputs of the control computing device, the outputs of which are connected to the actuators on the supply lines of the gas components from the tanks to the mixer and to the regulator of changing the ratio of gas and air supplied to an endogenerator, characterized in that, in order to improve the quality of chemical-thermal treatment, it is equipped with a pressure sensor and a part count sensor, etc. than pressure sensors and account details connected to the input of the control device.