SU789586A1 - Device for burnout control of water-cooled elements of high-temperature sets - Google Patents

Description

The invention relates to devices for controlling burnout of water-cooled elements of high temperature aggregates, for example, oxygen tuyeres, 5 probes for continuous monitoring of the temperature of molten steel, tuyeres of blast furnaces.

A device for controlling burnout of an oxygen lance containing photosensors located in the places of the alleged burnout of a water-cooled lance jacket, the outputs of which are connected to the input of the recorder I ^{* 1} ] · 15

The disadvantages of this device are the dependence of the sensitivity of the photosensor on the location of the latter to the burnout, i.e. depending on the degree of distance from the burnout site, the sensitivity of the photosensor drops sharply, the complex design of the water-cooling lance jacket when installing the photosensors does not accurately predict the possible 25 spots of burnout, which requires an increase in the number of photosensors, and hence the complexity of the device circuit. In addition, the complexity of installation and operation of the device increases due to the fact that the device operates in a liquid while in a movable lance, which affects the electrical insulation of the supply cables and the operation of photocells.

There is also known a device for controlling burnout of an oxygen lance containing at the inlet and outlet of a cooled lance jacket 10 flow sensors made in the form of flow meters, the outputs of which are connected to the subtraction unit, and the output of the latter through self-recording to sound and light alarms and to the input of the emergency shutdown unit . Lance burnout is judged by the difference signal of the flows at the inlet and outlet of the water-cooled lance jacket [2].

However, the sensitivity of this device allows you to determine the amount of leakage that corresponds to burnout is more than acceptable by technical standards, and does not allow to determine burnout or leak’s within the acceptable range, i.e. in the early stages of its occurrence. In addition, in the known device, its serviceability is not controlled by simulating the leakage of water and calibration is not carried out for a controlled leakage of water.

The purpose of the invention is to increase the reliability of the device.

This goal is achieved by the fact that the device for controlling burnout, tuyeres, contains flow rate sensors for the cooler * flow, one of which is installed at the inlet and the other at the outlet of the water-cooled jacket. The outputs of which are connected to the subtraction unit, and the output of the latter is connected via 10 a recording device for sound and light annunciators, an emergency shutdown unit, a jumper connecting the inlet and outlet pipelines, on which a flow meter and a controllable valve 'with a drive are installed, and the flowmeter output is connected chen to the input of the indicating device, the input of the drive of the controlled valve is connected to the remote control key jq.

The drawing schematically shows a block diagram of the proposed device.

The device consists of a constricting device - the diaphragm 1, installed at the entrance to the water-cooled jacket of the lance, a constricting device - the diaphragm 2, installed at the outlet of the latter. Giver 3 and abducer. ^{1, the} pipelines are connected by an intermediate jumper 5 on which a controllable valve 6 is mounted with an actuator 7 and a remote control key 8, and the input of the actuator 7 of the controllable valve 6 is connected to the remote control key 8. A flow meter 9 is also installed on the jumper, the output of which is connected to the indicating device 10. The constricting devices — diaphragms 1 and 2 are connected respectively to flow sensors — differential pressure gauges 11 and 12, pulse tubes 13 and 14. Differential pressure gauges 11 and 12 are installed at the input and output of _{(water-cooled} jacket. The outputs of pressure switches 11 and 12 are connected to the subtraction unit 15 inputs, whose output is connected to the input .16 automatic recorder and to one input of the comparator 17, the other input of the latter connected to the output allowable value setter 19 vTe The output of the allowable leakage comparison unit 17 is connected to the input of the emergency shutdown unit 19, which can be configured as an amplifier with a relay output.The recorder 16 is made with an alarm device, the output of which is connected to a light signaling device - lamp 20 and an audible signaling device with a siren 21 to give a pre-emergency alert.

The operation of the device is explained as follows.

The cooling water, passing through the diaphragms 1 and 2, creates pressure differences between dr _{and a} , which are supplied to the differential pressure gauges 11 and 12 via impulse tubes 13th 14.

The fluid flow rate F by the differential pressure across the diaphragm is determined by the formula

0'-ЛР _о 72р (рТр7), (1) (where сС is the flow coefficient taking into account the uneven flow distribution over the cross section;

F about - the area of the constricting device, 'p - the density of the fluid,, P ₂ ~ fluid pressure, respectively, before and after the diaphragm.

Denoting K = </ '£ o- [2p and ap = P4 “Ρς, equation (1) takes the form

Q-Kn / Zp No.

For aperture 1 we have:

(3) where is the water flow rate before the lance.

For aperture 2 we have:

© _a = K ₂ , (4) where Q ₂ is the water flow after the lance. Using the same differential pressure gauges to measure pressure drops across. diaphragms in the supply and outlet pipelines, you can select the parameters of the diaphragm so that the equality = K _{2 is} observed. Then, dividing (3) by (4) we get = m * * - or A,

Q _z '. ДР ₂ I На 'АР _and whence dr ₁ = ДР ₂ · () ^α .

A certain difference in pressure on the differential pressure gauges corresponds to a certain signal value, then by designating others, = and others _а = Зц, we write 3 ₄ = Зц.

In the absence of water leakage from the lance Q, = Q ₂ 'then ^r D ^a = Z _a .

In the presence of leakage, water by the value of & G, we have (6)

A change in water flow rate by & Q corresponds to a change in signals by & 3, therefore (7) and (7) in

3 ₂ = s ₄ - a 3

Substituting the values (6) (5) we obtain

3 ^ /--gdO)) I where

2-3 / aq ΔΟ ² ~ о С12 'З-ι (8)

-1

Since the second term of the right-hand side of equation (8) is a small second-order quantity, it can be neglected; then, 2> J-bQ b3 О 0 - X ---- or —— - 2 “—— * 9’

M 4 and Q

We express the dependence J - t (Q) in dimensionless quantities, for this section. The limiting function is J z q2 / ^ on where and Q are the current signal and flow rate, respectively, 3 ^, ^ q Q _waK, respectively, are the limiting nominal signal of the sensors and fluid flow rate. Then we get _

J / Q 'Whack / (ΐθί

Denote —3—

Then BUT) takes the form

Ϊ = V, (11)

®.e the relationship between the signal and the flow in dimensionless quantities pre10

- <V is a quadratic equation. 20 From equation (11) it follows that <maximum sensitivity = 2 with respect to the differential pressure will be at maximum flow rate, i.e. for Q = 1.

For q = 0.5, the sensitivities of the known and proposed devices are equal, with the same accuracy classes of control devices.

Based on the foregoing, the entire range of flow measurement can be divided into 2 areas, in the first of which 30 <<Ϊ <0.5, '0 <<0.5, and in the second 0.5 <ί <1; 0, 5 <φ <1.

From this we can conclude that in the second area, the use of differential pressure sensors 35 is more efficient than flow sensors.

The device operates as follows.

If there is a leak, through the diaphragms 1 and 2 of the impulse tubes 13 and 14, respectively, the differential pressure gauges 11 and 12 record various pressure drops, as a result of which a signal appears in block 15, which is transmitted to the recorder 16, and from it to the signaling devices 20 and '21, wherein the magnitude of the signal is proportional to the square of the magnitude of leakage, nature of which (or increase stability) traced posredst- ^ee vom automatic recorder 16.

When a lance burnout occurs, when the leakage is within acceptable limits, the operator is notified by signaling devices. 55

The permissible leakage amount setter 18 is set to the maximum allowable leak rate. When the signal increases from the output of the subtraction unit 15 and when it exceeds the signal from the dd output of the setter 18, the allowable leakage, a signal appears at the output of the comparison unit 17, which is transmitted to the input of the emergency shutdown unit 19. 65

When the unit 19 emergency shutdown stops supplying ¹ oxygen and cooling water, the lance is automatically removed from the bath of the Converter.

To check the health of the device periodically, for example 1 time per shift, an artificial water leak is created through the jumper 5 using a remote key 8 acting on the actuator 7 of the controlled valve 6. The leakage value is measured using _β flow meter 9 and indicating device 10. Simultaneously, an imbalance of signals differential pressure gauges 11 and 12 and a signal appears at the output of the subtraction block 15. The readings of the recorder 16 and the indicating device 10 are compared and, if necessary, calibrate the device.

. When calibrating the device on the jumper 5 create an artificial leak, which is regulated to a value exceeding the permissible.

According to the testimony of device 10, they calibrate the scale of the recorder 16 and adjust the response limits of the signaling devices, including the signaling devices 20 and 21.

The technical and economic efficiency of the device for controlling the burnout of the lance is that by increasing the sensitivity of the device, water leakage is detected in the early stages of burnout, which allows timely measures to be taken to prevent explosions and accidents caused by the falling of water into the converter, which reduces the number of downtimes and defective products, therefore, the productivity of converters increases.

Claims (2)

1. Author's certificate of the USSR 350828, cl. From 21 to 7/24, 1972. 2. HOKUSHIN-Japan Prospectus E 9-28, -19 Device for flow control, LSI -900.