JPS60201918A - Device for mixing gas with liquid - Google Patents

Abstract

PURPOSE:To obtain the desired mixing ratio of gas at a high speed in a device for mixing gas with plastic liquid component etc. by controlling a gas flow rate changing means through a measurement controller according to the mixing ratio of gas with liquid. CONSTITUTION:Liquid in a tank 10 is circulated by reciprocation of the piston 21 of a cylinder device 14 due to an actuator 22 through a flow passage 11 to mix gas by the 1st, 2nd gas blow-in device 15, 35. This gas mixing ratio is obtained on the basis of the data from an encoder 42 and a pressure sensor 43 at the arithmetic section 45 of a controller 44 and compared with the set valve of a memory section 46. When the gas mixing ratio is lower than the specified mixing ratio, gas is blown in from both the 1st and the 2nd gas blow-in device 15, 35 and when it reaches the set value the gas blow-in device 35 stops 13 and is mixed by the device 13 only. In this method the gas mixing ratio is elevated swiftly up to the desired air mixing ratio and can be accomplished at a high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for incorporating a gas into a liquid such as a plastic liquid component.

In reaction injection molding, in which a molded product is produced by colliding and mixing at least two plastic liquid components (liquids) that react with each other, the foam structure inside the molded product is made dense,
For the purpose of increasing product value by improving physical properties and appearance,
Air (gas) is mixed into plastic liquid components as fine bubbles. Conventionally, a liquid pump that circulates the plastic liquid component through the plastic liquid component flow path, a gas blowing device that mixes air into the plastic liquid component that flows through the flow path, and a plastic liquid component that flows through the flow path. Although a gas content measuring device for measuring the air content in the liquid component is provided, it has the disadvantage that the configuration is complicated and the operation is complicated.

In addition, if the plastic liquid component contains fillers such as glass fibers, the liquid pump will quickly wear out due to the filler, so in the above conventional equipment that uses a liquid pump, the filler is not included. The disadvantage was that plastic liquid components could not be used.

Therefore, the present applicant wishes to devise a device for mixing gas into liquid as shown in Fig. 1 (Japanese Patent Application No. 163706/1982).
. The device for mixing gas into this liquid includes a circulation cylinder device 3 that circulates the liquid in a liquid tank 1 through a liquid channel 2 connected to the liquid tank 1, and a circulation cylinder device 3 that circulates the liquid in a liquid tank 1 through a liquid channel 2 connected to the liquid channel 2. a gas blowing device 4 that mixes gas into the cylinder device 3; a pressure detection means 5 that detects the pressure inside the cylinder 3a of the cylinder device 3; and a piston 31 of the cylinder device 3.
), and the output of the pressure detecting means 5 and the position detecting means 6 are used to calculate the gas mixture rate in the liquid, and the calculated value is compared with a predetermined set value. As a result, the controller 7 for controlling the gas blowing device 4 and the controller 7 for controlling the gas blowing device 4 can be used for plastic liquid components containing fillers, and the cylinder device 3 It has a liquid circulation function and a gas entrainment rate measurement function, simplifying the configuration and improving operability.

Incidentally, in the above device, the flow rate of the gas mixed into the liquid is set to a constant value by the flow rate regulating valve 8, although this is also the case with conventional devices. However, when this set flow rate is increased, it becomes difficult to accurately achieve the target gas mixture rate, and conversely, when this set flow rate is decreased, the accuracy of achieving the target gas mixture rate increases, but it becomes difficult to achieve the target gas mixture rate. j' to the gas mixture rate! There was a complaint that it took a long time to complete the IJ.

In the present invention, a liquid circulation device is installed in the liquid flow path, a gas blowing device is installed in both the liquid flow path and the liquid tank, and a measurement and control device is used to detect the gas mixture rate in the liquid. The above-mentioned gas blowing device is configured to be comprehensively controlled to eliminate the above-mentioned conventional problem 1), and the target gas mixture rate can be achieved quickly and with high precision. The purpose of the present invention is to provide a device for mixing gas into liquid. Hereinafter, the present invention will be explained in detail based on the drawings.

Figures 2 to 4 show an embodiment of the present invention,
In the figure, 10 is a liquid tank that accommodates a plastic liquid component (liquid) of a high-pressure reaction injection molding machine. This liquid tank 10 has both ends 11a and 1 of a liquid flow path 11 made of piping.
1b is connected, and a stirring blade 13 rotated by a motor 12 is provided inside. The liquid in the liquid tank 10 is transferred to the liquid flow path 11.
A highly wear-resistant circulation cylinder device (liquid circulation device) 14 that circulates through the liquid flow path 11 and a first gas blowing device 15 that mixes gas into the liquid flowing through the liquid flow path 11 are provided. There is. That is, the liquid tank 10 is connected to the α ends of the first and second three-way switching valves 17 and 18, respectively, via the first switching valve 16, which is normally open. One end of the cylinder 19 of the circulation cylinder device 14 is connected to the β end of the cylinder 19 . Further, the other end of the cylinder 19 of the cylinder device 14 is connected to the β end of the second three-way switching valve 18, and inside the cylinder 19 is a piston provided at one end of a piston rod 20. 21 is slidably fitted. A piston 23 that slides within the actuator 22 is installed at the other end of the piston rod 20, and is operated by a hydraulic circuit (not shown) connected to both ends of the actuator 22.
The screw cylinder 21 of the cylinder device 14 is configured to reciprocate from side to side in FIG. 2. Then, when the piston 21 moves to the reverse end (the leftmost position in FIG. 2), the first three-way switching valve 17 is switched to the α end and the β end. At the same time, the second and third type switching valves 18 are also switched so that the β and γ ends of C1 are communicated with each other, and
- When the piston 21 moves to the forward end (the rightmost position in FIG. 2), the second and third type switching valve 18 is switched in conjunction with the movement, so that the α end and the β end are switched. At the same time as they are communicated with each other, the mode switching valve 17 is also switched so that its β and γ ends are communicated with phase H.

On the other hand, the γ end of the second three-way switching valve 18 is connected to the γ end of the first three-way switching valve 17 and one end of the first gas blowing device 15 via the second switching valve 24. The other end of the first gas blowing device 15 is connected to the liquid tank 10 via a check valve 25 and a third switching valve 26 which is normally open.

A gas supply source 2S is connected to the first gas blowing device 15 through a piping 27, and the piping 27 includes a gas pressure control valve 29, a gas pressure gauge 30, a gas pressure gauge 30,
first gas flow rate adjustment valve 31, first gas flow adjustment valve 32,
A first gas electromagnetic valve 33 and a first gas check valve 34 are provided. Further, the liquid tank 10 includes the liquid tank 1
A second gas blowing device 35 that mixes gas into the liquid in 0
is installed. The second gas blowing device 35 is connected between the gas pressure control valve 29 and the gas pressure gauge 30 of the pipe 27 via a pipe 36. In order from the second gas check valve 3
7. A second gas electromagnetic valve 38, a second gas flow meter 39, and a second gas flow rate adjustment valve 40 are provided.

Furthermore, the -V piston rond 20 has a measuring element/1.
A pinion 42a of an encoder 42 for measuring the position of the piston 20 is engaged with a rack 41.8 formed on one side of the measuring element 41. Further, the cylinder 1 of the cylinder device 14
9 is provided with a pressure sensor 43 for detecting internal pressure, and a control device 44 is attached to these encoder 42 and pressure sensor 43.

The control device 44 includes: ■Recorder 42 and pressure sensor 43;
A calculation unit 45 calculates the gas mixture rate for the liquid using the output from the calculation unit 45, and the measured value of the gas mixture rate calculated by this calculation unit 45 is used as a target value of the gas mixture rate stored in advance in the storage unit 46 and When the measured value of the gas mixture rate obtained by the calculation unit 45 is lower than the set gas mixture rate, the comparison unit 47 compares it with a predetermined set gas mixture rate that is less than the target value. Both the second gas solenoid valves 33 and 38 are opened, and when the measured gas mixture rate is lower than the target value and higher than the set gas mixture rate, only the first gas solenoid valve 33 is opened; , gas mixing rate S
1. If the measured value is higher than or equal to the target value, the 1st value is higher than or equal to the target value.
and a command section 48 that closes both of the second gas solenoid valves 33 and 38.
and the pressure sensor 43, and the command unit 48 is connected to the first and second gas solenoid valves 33' and 38, respectively.

Then, the encoder 42, pressure sensor 43, control device 44, etc. measure the gas mixture rate in the liquid, and based on the measured value, the first. Second gas blowing device 15.3
It constitutes a measurement control device @49 that comprehensively controls the 5.

J3, the liquid tank 10 contains hII as is well known.
r'! The cylinder device 50 and the mixing head 51 are connected,
The plastic liquid component supplied from the liquid tank 10 is sent to the mixing head 51, where it is mixed with other plastic liquid components sent from other measuring cylinder devices (not shown), etc., and a molded product is formed by the reaction of both liquid components. It is now possible to obtain Further, numeral 52 in the figure is a level meter for measuring the liquid level of the plastic liquid component in the liquid tank 10.

Next, the operation of the apparatus for mixing gas into a liquid according to the present invention configured as described above will be explained.

First, in order to circulate the liquid in the liquid tank 10 through the liquid flow path 11, the cylinder device 14 may be operated. However, when the piston 21 of the cylinder device 14 is retracted and moved to the leftmost position in FIG. At the same time, the second three-way switching valve 18 is switched, its β end and γ end are communicated, and the first, second, and third switching valves 16, 24, and 26 are each in an open state. There is. When a hydraulic circuit (not shown) is operated from this state to move the piston 23 in the actuator 22 to the right in FIG. The liquid in the device 14 flows from the other end of the cylinder 19 through the β and γ ends of the second three-way switching valve 18 and the second switching valve 24, and flows out into the liquid flow path 11.
Liquid flows into the cylinder 4 from one end of the cylinder 19 through the α and β ends of the first three-way switching valve 17. Therefore, the liquid in the liquid tank 10 is sucked into the cylinder device 14 in the order of the first switching valve 16, the first three-way switching valve 17, and the second three-way switching valve 18, as shown by the arrow in FIG. Second
The gas is fed under pressure through the switching valve 24 , the first gas blowing device 15 , the check valve 25 , and the third switching valve 26 in this order and circulated to the liquid tank 10 . Next, the piston 21 of the cylinder device 14 moves to the second position.
When moving to the rightmost position in the figure, the first three-way switching valve 17 is switched in conjunction with this, the β end and the γ end of A are communicated, and the second three-way switching valve 18 is switched, Its α end and β end are communicated. Then, when the hydraulic circuit is switched and the piston 23 in the actuator 22 is moved backward to the left in FIG. 2, the piston 21 of the cylinder device 14 is moved to the left in conjunction with this.
Cylinder i! The liquid in the device 14 flows from one end of the cylinder 19 through the β and γ ends of the first three-way switching valve 17 to the liquid flow path 1.
At the same time, liquid is caused to flow into the cylinder device 14 from the other end of the cylinder 19 through the α and β ends of the second three-way switching valve 18 . Therefore, the liquid in the liquid tank 10 is sucked into the cylinder device 14 in the order of the first switching valve 16 and the second three-way switching valve 18, as shown by the arrow in FIG. , the first gas blowing device 15 , the check valve 25 , and the third cutoff valve 26 in this order and circulated to the liquid tank 10 .

In this way, the hydraulic circuit is switched and the actuator 2
By reciprocating the piston 23 in the cylinder device 2 left and right, the piston 21 of the cylinder device 14 is reciprocated left and right, and the liquid in the liquid tank 10 is circulated through the liquid flow path 11.

Therefore, the mixing of gas into the liquid is the first problem. This is carried out by the second gas blowing device 15.35, and at that time, the control device 44 calculates the gas mixture rate in the liquid based on the output from the encoder 42 and the pressure sensor 43, and the calculated value is used to calculate the gas mixing rate in the liquid. 1st. Second gas blowing device 15
．． 35 in general.

That is, when calculating the gas mixture rate in the liquid, first, the α end and the β end of the second three-way switching valve 18 are communicated with each other, and the piston of the cylinder device 14 is opened with the second switching valve 24 closed. 21 from the right to the left, cylinder 19
Inhale liquid from the other end (see Figure 3 (a)). In order to reduce the internal pressure of one liquid, the piston 21 of the cylinder device 14 is connected to the β end and the γ end of the second and third type switching valve 18, with the liquid not flowing in from the α end. Move further to the left (Figure 3 (l))
reference). Next, the piston 21 of the cylinder device 14 is moved to the right to begin compression. And pressure sensor 43
As a result, the control device 44 detects that the preset first pressure point (low pressure) P+ has been reached, and the piston stroke 1 at that point is read by the encoder 42 (see FIG. 3(c)). Further, the pressure lens 43 detects when the second loaf force (high pressure) P2 preset by the control device 44 is reached, and the encoder 42 reads the piston stroke J2 at that point.

These measurement data PI, P2, Jl, and J2 are sent to the calculation unit 45 of the control device 44, and the gas mixing rate Xa in the liquid under atmospheric pressure is calculated using the following equation.

Xa-πD2J PI P2 /N However, N-4,132 (Vo +VP -πI)2 J+//
l)x (P2 −P+ )+πD”JP2X (P+
-1,033') Note that this formula was determined as follows.

In other words, (1) The state equation for gas <pv=constant) also holds true when mixed with liquid.

(2) Liquids are incompressible.

And Pa: Atmospheric pressure (1,033 kg/cvr2
) Pl: First pressure condition k (1/cm' (absolute pressure)
P2: Second pressure condition k (1/cf (absolute pressure)) Vm:
Liquid body V4cm' Va: Volume of mixed gas under Pa V+: Volume of mixed gas under P+ d v2: Volume of mixed gas under P2 ClT1'vo Volume of cylinder 19 C Go Vt: Cylinder below P+ The total volume of liquid and gas in cylinder 19 under P2 is 1 volume fAcwi VS: Total volume of liquid and gas in cylinder 19 below P2 d vP : Pipe internal volume d Jl : From encoder 42 origin a to the point where the pressure becomes Pl = distance 1 from the point where the pressure becomes Pl to the point C where the pressure becomes Pl (J=J2-1+ > D Take the diameter C of Niji cylinder 19. From the gas state equation, 1 .033Va -P+ VI =P2 V2 Therefore, V+=1.033Va/P+ --(1) Vz=1.0
33Va/P2 --(2)VI V2 =1.033
Va
Vsu -Vo -πD' J l/ 4 -- (5)
From formulas (1), (4), and (5), Vm = Vt +Vp V+ = Vo -7 (D2 J I/4+Vp-1, 033V
a / P + --(6) Zarani, VI V2=πP2ノ/4 ・・・・・・(7)(3)
, From formula (7), ■a=πD2J PI Pl / (4X1.033
(Pl PI )) ... (8) Gas mixing rate Xa is X
Since a = Va / (Vi + Va),
From equations (6) and (8), ×a=πD2J PI Pl /N where N=4.13 '2 (Vo +Vp -πD2j+
/4) (Pl-P+-) +πD2 jP2 (P+ ' 1.033) When the gas mixture rate is calculated in the calculation unit 45 of the control device E44 based on the measurement data P1, Pl, Jl, and J2 in this way, The calculation result is compared with the target value of the gas mixture rate stored in advance in the storage unit 46 and a predetermined set gas mixture rate lower than the target value in the comparison unit 47, and the result is sent to the command unit 48 and 1. Second gas blowing device 15゜3
5 is controlled. That is, when the comparator 47 determines that the measured value of the gas mixture rate obtained by the calculation unit 45 is lower than the set gas mixture rate, the command unit 48 controls both Ml and the second gas solenoid valve 33.38. hear. Then, the gas sent from the gas supply source 28 is mixed into the liquid in both the liquid flow path 11 and the liquid tank 10 by the first gas and second gas blowing devices 15.35, and the cylinder device 1
4 and switching valves 17, 18, 24, the liquid is circulated within the liquid channel 11 and the liquid tank 10.

On the other hand, if the comparator 47 determines that the measured value of the gas mixture rate is higher than the set gas mixture rate and lower than the target value, the command unit 48 releases only the first gas solenoid valve 33, and controls the second gas mixture rate. Solenoid valve 38 is closed. As shown, the gas from the gas source 28 is mixed into the liquid in the liquid channel 11 only by the first gas blowing device 15, and the liquid is circulated in the same manner as described above. Furthermore, when the comparison unit 47 determines that the measured value of the gas mixing rate is higher than or equal to the target value, the command unit 48 outputs the first. Second gas solenoid valve 3
3. Close both of 38 and stop mixing of gas. Then, the liquid is circulated in the same manner as described above, but at that time, if necessary, the liquid tank 10 is replenished with liquid that is not mixed with gas.

As described above, in the device for mixing gas into liquid according to the present invention, if the gas mixing rate is lower than the set gas mixing rate, the first. Since gas is mixed into the liquid by both the second gas blowing devices 13 and 35, the speed of gas mixing is fast;
The gas mixing rate increases rapidly, but when the gas mixing rate reaches the set gas mixing rate, the second gas blowing device 35 is stopped,
Since the gas is mixed only by the first gas blowing device 15, the gas mixing rate is reduced, and the target gas mixing rate can be achieved with high accuracy. In other words, by increasing the number of gas blowing skewers using the first gas blowing device @15, the gas mixing rate can be rapidly increased, but the measurement interval of the gas mixing rate is, for example, about 30 air, and this Since it cannot be further shortened, gas is blown into the colander when the gas mixture rate approaches the target value. On the other hand, if the gas injection rate ♀ is reduced, the target value of the gas mixture rate will be reached (it takes time. Therefore, in the apparatus of the present invention, the liquid tank 10 is provided with a second gas injection device. 35
is provided, and both gas blowing devices 10 and 35 blow gas until a predetermined gas mixing rate is reached, thereby rapidly increasing the gas mixing rate.

Here, it is possible to provide a plurality of gas blowing devices only in the liquid channel 11, but since the capacity of the liquid tank 10 is, for example, about 250 J, the amount of liquid circulated by the cylinder device 14 is For example, 10 J%m! Since the amount of liquid Ill is small, a large amount of gas is blown into the liquid flow path 11 where the liquid Ill is small, and the gas may not become fine bubbles.

Therefore, in order to rapidly increase the gas flj population rate,
Preferably, gas is blown into the liquid tank 10.

By the way, the liquid mixed with gas is sent from the liquid tank 10 to the mixing head 51 by the metering cylinder device 50 at regular time intervals, or the liquid in the liquid tank 10 is reduced to a low level and does not contain the new IC gas. Even in the state J3 where the liquid is supplied to a high level in the liquid tank 10 and the amount of liquid without gas increases rapidly, the supply of liquid to the mixing head 49 continues. shi/koga-)
In order to keep the gas mixing rate in the liquid uniform, it is necessary to increase the gas mixing rate especially in the above cases.
In such cases, the apparatus of the present invention is extremely effective.

In the above embodiment, the cylinder device 14 was used for liquid circulation in consideration of wear resistance, etc., but if there is no need to take wear resistance etc. into consideration, the cylinder device 14 may be used as in the conventional case. It is possible to use a liquid pump.

In addition, in the above, the liquid flow path 11 and the liquid tank 10 have a first
．． Second gas blowing device 15. Although one gas blowing device is provided in each of the liquid passages 11 and the liquid tank 10, the effects described in Section 2 can be more effectively achieved if a plurality of gas blowing devices are provided in both the liquid flow path 11 and the liquid tank 10. Further, the control device 44 may be provided with a control function to control the gas blowing device 15.35 depending on the level of the liquid tank 10 to change the gas mixing rate.

As explained above, when gas is mixed into the liquid of the present invention,
! In the i-position, gas blowing devices are installed in both the liquid flow path and the liquid tank, and these gas blowing devices include
Since a measurement control device i=J is installed that measures the gas mixture rate in the liquid and controls these gas blowing devices overall based on the measured value, the gas mixture can be controlled according to the gas mixture rate. By freely changing the speed, the target gas mixing rate can be achieved quickly and with high precision.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an improved conventional device for mixing gas into liquid; FIGS. 2 to 4 show an embodiment of the present invention; FIG. 2 is a schematic configuration diagram; Figure (a),
(B) and (C) are explanatory diagrams showing the procedure for determining the gas mixing rate, and Figure 4 (A), (B), and (C) are explanatory diagrams showing the conditions under each pressure. It is. 10...Liquid tank, 11...Liquid flow path, 14...Cylinder equipment @ (liquid circulation vA device 1
ffi), 15...first gas blowing device, 35
...Second gas blowing device, 49...Measurement control device. Applicant: Niigata Iron Works Co., Ltd. Figure 3 C A] Figure 4 f I J (0) (Ha 1

Claims (1)

[Claims] A liquid flow path connected at both ends to the liquid tank is provided with a liquid circulation device that circulates the liquid in the liquid tank through the liquid flow path, and both the liquid flow path and the liquid tank are provided with a liquid circulation device that circulates the liquid in the liquid tank through the liquid flow path. A gas blowing device that mixes gas into the liquid in the liquid is installed, and the gas blowing device measures the gas mixing rate in the liquid and blows these gases based on the measured value. 1. A device for mixing gas into a liquid, characterized in that it is equipped with a measurement control device that controls the device overall.