JPS6158219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of continuously mixing a liquid and a powder in the same molar ratio.

Generally, when trying to mix a liquid and a powder according to the molar ratio, the liquid and powder are measured separately using a weighing scale.
Supply and mix these to a tank equipped with an agitator, or
Alternatively, it is carried out using a mixing device as shown in FIG.

That is, put the powder into the scale hopper 1,
The weight of the hopper is subtracted from the total weight of the powder and the hopper to determine the powder weight, which is sent to the hopper 2 of the feeder, and the powder is quantitatively fed to the mixing tank 4 by the screw feeder 3. On the other hand, a method is implemented in which the liquid is measured with a gravimeter, supplied to a mixing tank 4, and mixed with an agitator 5 to obtain a mixed liquid.

However, since all of the above mixing methods involve intermittent operations, they have the disadvantage that they cannot be used in processes that require continuous operations. Furthermore, when using a scale hopper as shown in Fig. 1, the flexible tube 6 installed between the scale hopper 1 and the hopper 2 of the feeder deteriorates weighing accuracy, and the location where the scale hopper is installed may be affected. The drawback was that it required a large amount of money.

An object of the present invention is to solve the above-mentioned conventional drawbacks, and has the following configuration.

That is, the liquid is measured by a flow meter, the measured value of the liquid is set in the controller, and then the liquid is continuously supplied to the mixer, and the powder is supplied to the mixer and mixed. A mixture of liquid and powder continuously discharged from the mixer is measured by a mass flowmeter, and the measured value of the mixture is set in the controller,
A liquid characterized in that the measured value of the mixed liquid and the measured value of the liquid are compared by the controller, the difference is calculated, and the amount of powder supplied to the liquid is controlled based on the difference. and powder mixing method.

The configuration of the present invention will be explained below based on the drawings.

2 to 4 are schematic system diagrams of a mixing device applied to the present invention.

In FIG. 2, 11 is a liquid storage tank;
Reference numeral 2 denotes a first liquid feeding pump, one end of which is connected to the storage tank 11, and the other end connected to the first mass flow meter 13.

14 is a first return pipe, one end of which is connected between the first liquid feeding pump 12 and the first mass flow meter 13, and the other end connected to the storage tank 11.

15 is a first flow control valve, one end of which is connected to the first flow control valve;
The liquid feeding pump 12 is connected to the mixing tank 16 at the other end. 17 is a stirrer provided in the mixing tank 16, and 18 is a liquid level detector. Reference numeral 19 denotes a second liquid feeding pump, one end of which is connected to the mixing tank 16 and the other end connected to the liquid feeding pipe 20.

21 is a second return pipe, one end of which is connected to the liquid sending pipe 2.
0, and the other end is connected to a mixing tank 16. 22 is a second flow rate control valve, one end of which is connected to the liquid sending pipe 20.
The other end is connected to a second mass flowmeter 23.
24 is a powder hopper, and 25 is a screw feeder.

26 is a controller consisting of a supply amount setting circuit, a comparison calculation circuit, an operation command circuit, and the like.

The supply and mixing operations of liquid and powder in the mixing device having the above configuration will be explained.

First, a predetermined liquid A is supplied to the storage tank 11, and powder B is supplied to the hopper 24. Next, the mixing device is started, an operation command signal is sent from the controller 26 to the first liquid feeding pump 12, the first liquid feeding pump 12 is rotated, and the liquid A in the storage tank 11 is sucked,
and sends it to the first mass flow meter 13.

When the liquid A is sent to the first mass flow meter 13, it is detected as a weight flow rate, and the signal is sent to the controller 26 from time to time. When the signal is sent to the controller 26, it is compared with a preset supply amount, and if the value is greater than the set amount, an operation command signal is sent to the first flow rate control valve 15, and the degree of opening of the valve is adjusted. A regulated and set amount of liquid A is supplied to the mixing tank 16, and the excess liquid is returned to the storage tank 11 through the first return pipe 14. When the liquid A is supplied to the mixing tank 16, the controller 26 sends the screw feeder 25 for powder supply.
A preset amount of powder B is supplied to the mixing tank 16.

At the same time as sending the powder B supply operation command signal,
An operation command signal is sent to the stirrer 17 to rotate it, stirring the liquid A and the powder B to form a mixed liquid C. When a predetermined amount of liquid A and powder B are supplied to the mixing tank 16, an operation command signal is sent from the controller 26 to the second liquid feeding pump 19, which rotates the pump.
The mixed liquid C in 6 is sucked and sent to the liquid sending pipe 20. When liquid A and powder B are supplied, mixing tank 1
The liquid level position of the mixed liquid C in the liquid mixture C is detected by the liquid level detector 18, and the signal thereof is sent to the controller 26 from time to time.

If the liquid level signal sent to the controller 26 is below the set position, the controller 26 sends a second
Sends an operation command signal to the flow rate control valve 22, closes it,
The mixed liquid C sent out from the second liquid sending pump 19 is returned to the mixing tank 16 through the second return pipe 21. If the liquid level signal sent to the controller 26 is above the set position, the controller 26 sends an operation command signal to the second flow control valve 22, opens the valve, and starts the second liquid supply. The mixed liquid C sent out from the pump 19 is sent to the second mass flow meter 23.

The delivery of the mixed liquid C to the second mass flow meter 23 is made constant by adjusting the degree of opening of the second flow rate control valve 22 so that the liquid level in the mixing tank 16 is always constant. When the mixed liquid C is sent to the second mass flow meter 23, it is detected as a weight flow rate, and the signal thereof is sent to the controller 26 from time to time. Controller 26
The weight flow rate of the mixed liquid C sent to the liquid mixture C is temporally matched with the weight flow rate of the liquid sent before, and a comparison calculation is performed, and the supply error of the powder B is detected based on the difference, and the controller An operation command signal is sent from 26 to the screw feeder 25 to adjust the amount of powder B supplied so that the mixture C always has a set molar ratio and is sent to a receiving tank or reaction tank (not shown). .

Next, the configuration of the embodiment of the mixing device shown in FIG. 3 will be explained.

31 is a liquid storage tank, 32 is a flow rate regulating pump, one end of which is connected to the storage tank 31, and the other end is connected to the first
It is connected to a mass flow meter 33. 34 is a mixing tank, and a stirrer 35 is provided. 36 is mixing tank 3
4 is a liquid level detector provided, and 37 is a liquid feeding pump.

38 is a static mixer, one end of which is connected to a liquid feeding pump 37 and the other end connected to a liquid feeding pipe 39.

40 is a return pipe, one end of which is connected to the liquid sending pipe 39
The other end is connected to a mixing tank 34.

41 is a flow rate control valve, one end of which is connected to the liquid feed pipe 3.
9, the other end is connected to a second mass flow meter 42. 43 is a powder hopper, and 44 is a screw feeder. 45 is a controller consisting of a supply amount setting circuit, a comparison calculation circuit, an operation command circuit, and the like.

The supply and mixing operation of liquid and powder in the mixing device having the above configuration will be explained.

Liquid A and powder B are supplied to the storage tank 31 and hopper 43, respectively. Next, the mixing device is started, an operation command signal is sent from the controller 45 to the flow rate adjustment pump 32, the flow rate adjustment pump 32 is rotated, and the storage tank 3
1 is sucked in and sent out to the first mass flow meter 33. When the liquid A is sent to the first mass flow meter 33, it is detected as a weight flow rate, and its signal is sent to the controller 45 from time to time. When the signal is sent to the controller 45, it is compared with a preset supply amount, and an operation command signal is sent to the flow rate adjustment pump 32 so that the supply amount is always constant.
The amount of liquid to be fed is adjusted and the liquid is supplied to the mixing tank 34.

When liquid A is supplied to the mixing tank 34, the controller 4
5 sends an operation command signal to the screw feeder 25 for powder supply, and a preset amount of powder B is supplied to the mixing tank 34. At the same time as sending the supply operation command signal for the powder B, an operation command signal is sent to the stirrer 35 to rotate the stirrer and stir the liquid A and the powder B to form a mixed liquid C. When a predetermined amount of liquid A and powder B are supplied to the mixing tank 34, an operation command signal is sent from the controller 45 to the liquid feeding pump 37 to rotate the pump and mix liquid C in the mixing tank 35. Aspirate, pump and send to static mixer 38.

When the mixed liquid C is sent to the static mixer 38, it is further mixed and sent to the liquid sending pipe 39. When the liquid A and the powder B are supplied, the liquid level position of the mixed liquid C in the mixing tank 34 is detected by the liquid level detector 36, and the signal thereof is sent to the controller 45 from time to time. If the liquid level signal sent to the controller 45 is below the set position, the controller 45 sends an operation command signal to the flow rate control valve 41 to close it and send the liquid out from the liquid feeding pump 37. The mixed liquid C passes through the static mixer 38 and the return pipe 40 to the mixing tank 35.
will be returned to.

If the liquid level signal sent to the controller 45 is above the set position, the controller 45 sends an operation command signal to the flow rate control valve 41 to open it, and the liquid feed pump 37 Mixed liquid C sent out
is sent to the second mass flow meter 42 through the static mixer 38, liquid feed pipe 39, and flow rate control valve 41. The delivery of the mixed liquid C to the second mass flowmeter 42 is made constant by constantly adjusting the degree of opening of the flow control valve 41 so that the liquid level in the mixing tank 35 is constant.

When the mixed liquid C is sent to the second mass flow meter 42,
It is detected as a weight flow rate, and its signal is sent to the controller 45 from time to time. The weight flow rate of the mixed liquid C sent to the controller 45 and the weight flow rate of the liquid sent before are made to match in time and are compared and calculated, and the supply error of the powder B is detected based on the difference. , controller 45
An operation command signal is sent to the screw feeder 44 to adjust the amount of powder B supplied so that the mixed liquid C always has a set molar ratio and is sent to a receiving tank or a reaction tank (not shown).

Next, the configuration of the embodiment of the mixing device shown in FIG. 4 will be explained.

51 is a liquid storage tank, and 52 is a first flow rate regulating pump, one end of which is connected to the storage tank 11 and the other end to the first mass flow meter 53.

54 is a mixer, which is formed by a liquid introduction pipe 54a and a diffusion mixing section 54b. 55 is a second flow rate regulating pump, one end of which is connected to the mixer 54;
The other end is connected to a second mass flow meter 56.

57 is a powder hopper, and 58 is a screw feeder for powder supply. Reference numeral 59 denotes a controller comprising a supply amount setting circuit, a comparison calculation circuit, an operation command circuit, and the like.

The supply and mixing operation of liquid and powder in the mixing device having the above configuration will be explained.

Liquid A and powder B are supplied to storage tank 51 and hopper 57, respectively. Next, the mixing device is started, an operation command signal is sent from the controller 59 to the flow rate adjustment pump 52, the flow rate adjustment pump 52 is rotated, and the liquid A in the storage tank 51 is sucked and sent out. It is sent to mass flow meter 53. When the liquid A is sent to the first mass flow meter 53, it is detected as a weight flow rate, and the signal is sent to the controller 59 from time to time.

When the signal is sent to the controller 59, it is compared with a preset supply amount, and an operation command signal is sent to the flow rate adjustment pump 32 so that the supply amount is always constant, and the amount of liquid sent is adjusted. It is sent to mixer 54. When the liquid A is sent to the mixer 64, the controller 59 sends the screw feeder 58 for powder supply.
An operation command signal is sent to the mixer 54, and a preset amount of powder B is supplied to the mixer 54.

When the liquid A is sent to the mixer 54, the liquid A is discharged from the introduction pipe 54a to the diffusion mixing section 54b, becomes a negative pressure in the discharge section, sucks the powder B, and then enters the diffusion mixing section 54b. Liquid A and powder B are mixed to form mixed liquid C. When a predetermined amount of liquid A and powder B are supplied to the mixer 54, an operation command signal is sent from the controller 59 to the second flow rate regulating pump 55 to rotate the pump, and the mixed liquid C in the mixer 54 is is aspirated and sent to the second mass flow meter 56.

When the mixed liquid C is sent to the second mass flow meter 56,
It is detected as a weight flow rate, and its signal is sent to the controller 59 from time to time. When the signal is sent to the controller, it is compared with a preset amount of liquid to be sent, and an operation command signal is sent to the flow rate adjustment pump 55 so that the amount of liquid to be sent is a predetermined amount, and the amount of liquid to be sent is adjusted. and sent to a receiving tank or reaction tank (not shown).

The weight flow rate of the liquid A sent from the first mass flow meter 53 and the weight flow rate of the mixed liquid C sent from the second mass flow meter 56 are temporally matched and compared, and the difference is calculated. The controller 59 then sends an operation command signal to the screw feeder 58 to adjust the supply amount of powder B so that the mixture C always has the set molar ratio. and sent to a receiving tank or reaction tank (not shown).

Although the present invention can be implemented as described above, it is not limited to the embodiments described above.

A mass flowmeter is preferably used as the liquid flowmeter, but a volume type, differential pressure type, area type, or electromagnetic type flowmeter may also be used.

If it is necessary to stir the liquid in the liquid storage tank, a stirrer may be provided, or a circulation circuit may be formed with a liquid sending pump, a return pipe, etc. to circulate and stir the liquid.

The amount of liquid supplied may be adjusted by controlling the degree of opening of a flow rate control valve, or may be performed by controlling the amount of liquid fed by a liquid feeding pump. The flow control valve or the liquid sending pump may be controlled via a controller, or may be controlled in conjunction with a mass flow meter.

The mixing operation of liquid and powder in the mixer is performed in the second
The mixture may be mixed using a mixer having a liquid introduction pipe and a diffusion mixing section such as the embodiment shown in FIGS. Alternatively, the mixture may be mixed by forcibly circulating the liquid between the mixing tank and the mixing tank using a liquid sending pump, or a static mixer may be provided for mixing, or a combination of the above-mentioned agitator and a circulating or static mixer may be used for mixing. You can also.

If the mixer is a tank, it may be a cylinder, pipe, etc., but the smaller the capacity and cross-sectional area, the better the control accuracy.

The liquid level detector may be a non-contact type such as a photoelectric detector or an ultrasonic detector; it may be a pressure-sensitive type that detects by directly contacting the liquid, or a contact type that detects the liquid level position by the pressure of the solution. It can be anything. The operation of the flow control valve based on the detection of the liquid level may be performed via a controller, or the liquid level detector and the flow control valve may be operated in conjunction with each other.

The powder feeding device may be appropriately selected depending on the particle size, stickiness, etc. of the powder, such as a screw feeding device or a vibration feeding device.

The operation of the liquid feed pump, flow control valve, powder feeder, etc. may be controlled by a controller having a supply amount setting circuit, a comparison calculation circuit, an operation command circuit, etc. , an arithmetic unit, a timer, etc. may be appropriately connected and controlled.

By having the above configuration, the present invention has the following features:
It has the following effects.

(a) It is possible to supply and mix liquid and powder according to the molar ratio.

(b) Liquid and powder supply and mixing operations can be performed continuously.

(c) Weight scales such as scale hoppers are not required for weighing powder, and the space and cost for installing them are also eliminated.

(d) Even if the viscosity of the liquid changes, it can be metered and dispensed with almost no effect.

(E) By simply keeping the liquid level in the mixing tank constant, a fixed amount of mixed liquid can be fed continuously or intermittently by opening and closing the valve, without the need for a high-precision liquid pump or flow meter.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of a conventional mixing device. 2 to 4 are schematic system diagrams of the apparatus applied to the present invention. 11, 31, 51: storage tank, 12: first liquid pump, 13, 33, 53: first mass flow meter, 14:
First return pipe, 15: First flow control valve, 16,3
4: Mixing tank, 17, 35: Stirrer, 18, 36:
Liquid level detector, 19: Second liquid feeding pump, 20, 3
9: Liquid sending pipe, 21: Second return pipe, 22, 42: Second flow rate control valve, 23, 42, 56: Second mass flow meter, 24, 43, 57: Hopper, 25, 44,
58: screw feeder, 26, 45: controller,
32: Flow rate adjustment pump, 37: Liquid feeding pump, 3
8: static mixer, 40: return pipe, 41: flow rate adjustment valve, 52: first flow rate adjustment pump, 54: mixer, 55: second flow rate adjustment pump.

Claims (1)

[Claims] 1. A liquid is measured by a flowmeter, the measured value of the liquid is set in a controller, and then the liquid is continuously supplied to a mixer, and the powder is supplied to the mixer. The mixture of liquid and powder continuously discharged from the mixer is measured by a mass flow meter, the measured value of the mixed liquid is set in the controller, and the measured value of the mixed liquid is A method for mixing liquid and powder, characterized in that the measured value of the liquid is compared with the measured value of the liquid by the controller, the difference is calculated, and the amount of powder supplied to the liquid is controlled based on the difference. 2. The method of mixing liquid and powder according to claim 1, wherein the liquid mixture is discharged from the mixer while the liquid level in the mixer is maintained constant.