SU558003A1 - Apparatus for determining melt depth velocities - Google Patents

Description

one

The invention relates to the glass industry, but can be used in other areas of the industry: metallurgical, chemical.

A device for determining the melt depth velocities is known, which contains thermocouples located in two or more furnace points along its length and recording devices 1.

A device for determining the melt depth velocities is known, which comprises piezometric tubes located in a flow of a controlled medium and connected to a pressure differential sensor and to a source of gas supply through electropneumatic valves 2.

A disadvantage of the known devices is low sensitivity, which requires the use of sophisticated pressure drop meters. For example, to measure depth velocities of a glass melt, the magnitude of which is several meters per hour, it is required to measure the pressure drop in Pa at a pressure value in the tubes of more than 10,000 Pa.

The invention is an improvement in measurement accuracy. This is achieved by the fact that the device includes chokes, electric actuators of tubes with oscillators, a displacement transducer with opening contacts, a commanding device with closing contacts, secondary viscosity gauges, pressure drop and melt velocity, an average viscosity meter, integrators, a zero-organ and

electromozzo. Moreover, the differential pressure sensor is connected through one of the closing contacts of the controller to the secondary devices of viscosity and differential pressure. Secondary viscosity devices are connected to one of the inputs of the melt velocity meter through an average viscosity meter, the output of which is connected to the integrator via the corresponding closing contact of the controller. Another input melt velocity meter

-connected through a second integrator and an electro-coupling to the output of the secondary differential pressure device, the measurement circuit of which includes other closing contacts of the controller and closing contacts of starters. The throttles are connected in parallel with the electropneumatic valves, the control circuit of which includes the other closing contacts of the co-apparatus, and the piezometric tubes are mechanically connected to

electrically driven and with displacement sensor. A device for determining the melt depth velocities is shown in the drawing and comprises piezometric tubes 1 and 2, a differential pressure sensor 3, throttles 4 and 5,

electropneumatic valves 6 and 7, gas supply source 8, 9 tube electric actuator, displacement sensor (herka) 10 with disconnecting contacts 11 and 12, comaid device 13 with closing contacts 14-28, closing contacts 29-34 actuators, secondary devices 35, 36 in viscosity, 37 differential pressure and 38 speeds of melt glass mass, a meter 39 of average viscosity, integrators 40, 41, zero-orgap 42, and an electrofusion 43.

The speed of movement of any t-ro layer of glass mass with a thickness of LN at the level L can be determined from the equilibrium force equation shifting (fc) this layer relative to the adjacent layer and retarding (/ t) due to friction during sliding of the layers with relative velocity Dso. Shear force

/with. - 1 Р, (fi) - Р, (h) dh 2 (Я.-Яа) гД / г.

where is the number of layers, P {(h) -Pi (h) is the difference of hydrostatic pressures, and the friction force

city department

/ t. V-i-rr

Dy

where L is the distance between the tubes, c, is the average viscosity of the glass mass in this layer, whence

1 L

1 / s .,. YES.

 J i

The device for determining the depth speeds of the melts works as follows.

Through the contacts 34 of the actuator include the actuator 9 to move the piezometric tubes 1 and 2 down. When moving by a predetermined amount of A / g, the contacts of the displacement sensor (reed switch) 10 are triggered, which turn off the electric drive and turn on the commander 13. The gas into the piezometric tubes is supplied from source 8 through the throttles 4, 5, which are set to deliver a minimum flow rate, The sensor 3 measured in the tubes is proportional to the difference in hydrostatic pressures P, –P at the measurement points. With the closure of the contacts 22 and 24 of the control unit, the measurement result is transmitted to the secondary device 37 of the differential pressure and stored on the integrator 40 due to the interruption of the switching circuit of the electro-coupling 43 upon opening of the contacts 25. After closing the contacts 23 and 28, the measuring circuit 37 instead of the sensor 3 switches to zero the organ 42 and the instrument needle are reset. Starter pins 29 and 30 are closed for the entire measurement time when tubes are moved down. Then contacts 14 are closed and the drive is turned on for further downward movement. In this case, after opening the contacts of the reed switch 10, the command device takes the initial position, and the drive circuit closes through the normally closed contacts 11 of the reed switch. The drive stops when the tubes are lowered on

specified value. Thus, through each segment, the integrator 40 performs a sigal proportional to the pressure drop (PI - PZ} -, and when lowered into the bottom layers,

where the speed of the current of the glass melt is close to zero, its output signal is proportional to the shearing force.

At the lowest low point, the drive switches over to a lift through the contacts 31 of the starter.

piezotube. Simultaneously contacts 32 and

The starter switches the measurement circuit of instrument 37 so that instead of summing the signals from the instrument on integrator 40, they are subtracted. As the piezotube is raised to the height A / i, the drive stops and the control unit is turned on by the contacts of the reed switch. First, contacts 22-25 are closed, 28 - the value of pressure difference (Pi-Pz) n is removed from sensor 3, and the value of the shear force is fixed at the output of integrator 40

/ e ("- l) SVi / 2) iA / l.

During the subsequent operation of the contacts 14, the drive does not turn on, since the contacts

The starter is open, and the control unit continues to work.

After the contacts 16, 20, 21 are triggered, the solenoid 6 and the gas flow through the tube 1 are opened, and consequently, the frequency of detachment of gas bubbles increases, and the pressure in the tube becomes proportional to the hydrostatic pressure P and the viscosity PI + + / ((. is fixed on the secondary device 36. Similarly, when the contacts 17, 18, 19 and the solenoid 7 are turned on, the device 35 records the pressure difference PZ IJ Z-PI The sum of the output voltages supplied from the devices 35 and 36 to the meter 39, proportional to the average viscosity in a test glass layer

„(I-h + -2)„

Vn -

The signals from the meter 39 and the integrator 40 are fed to the device 38 of the melt rate of the glass melt according to the division scheme. When the contacts are closed 26, the result of dividing

/ s ("- 1)

stored on the device 38, and then through the contacts 27 and transmitted to the integrator 41, performed according to the scheme of the integrator 40. After the completion of the integration operation, the contacts 15 are closed and the drive turns on

rise. After a predetermined height L / t, the drive stops (the co-tact 12 of the reed switch opens) and the measurement cycle is repeated. The integrator 41 fixes the flow rate of the next layer of glass. When connected

to the integrator of the recorder can

It is necessary to draw a plot of the melt velocity over the entire depth of the furnace or channel.

The measurement accuracy consists of the measurement error of the difference in hydrostatic pressures of 1% (industrial differential pressure gauges of the type DKE, etc.), viscosity - instrumental error (differential pressure gauge - secondary device) 1% and methodical about 2% (depends on the measurement of factors affecting the formation of bubbles gas), as well as the error of the operations of the calculation (division, integration) of about 1%.

Taking into account the different measurement method, the nature of the velocity profile can be determined with an error of less than 5%. Such accuracy cannot be obtained by using direct methods of measuring the flow rate, for example, by the pressure exerted by the flow on the sensor placed in the test medium, in connection with a small amount of the flow velocity.

Measurement of melt depth velocities, in particular glass melt at various points in the furnace basin and channels, will allow to determine the furnace productivity, thickness and velocity of convection currents and thereby control the melting processes taking into account changes in temperature fields in the melt, glass melt dynamics, create optimal conditions for heat transfer under the charge with the flow of glass for the processes of clarification and homogenization, and consequently, to obtain a glass melt of high quality (thermally and chemically homogeneous).

Claims (2)

1.Patent of France No. 1351160, cl. S OZ 5/00, 1965. 2. Attent USA No. 3482956, cl. 65-136, 1969. 23