JPH07117045A - High-pressure urethane injecting device - Google Patents

Abstract

PURPOSE:To obtain a high-pressure urethane injecting device capable of easily controlling each material to a predetermined temperature just before a mixing position and eliminating a problem caused by an operational failure of a high/ low pressure change-over valve. CONSTITUTION:Material tanks 11, 12 are connected to a mixing head 21 provided with material temperature measuring sensors T1, T2 through forward pipes 31, 32 for forcibly feeding respective materials from the material tanks 11, 12 to the mixing head 21 at the time of a delivery and a non-delivery circulation and return pipes 41, 42 for returning the respective materials from the mixing head to the material tanks at the time of a non-delivery circulation. On the other hand, the material supply sides of the material tanks are connected to the midway points of the return pipes through auxiliary circulation pipes 43, 44 for forcibly feeding the respective materials from the maternal tanks to the return pipes. In the return pipes, heat exchangers 47, 48 are provided between the connecting parts to the auxiliary circulation pipes and the material tanks.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a high pressure urethane injector.

[0002]

2. Description of the Related Art A high-pressure urethane injection device is one in which a polyol-side raw material and an isocyanate-side raw material are pressure-fed from each raw material tank to a mixing head, and the mixing head collides and mixes them and then discharges them from a discharge port at the tip of the mixing head. .

In a conventional high-pressure urethane injecting apparatus, as shown in FIG. 2, each of a polyol-side raw material tank 61 and an isocyanate-side raw material tank 62 has raw material pumps p ₁ and p ₂ for feeding respective raw materials under pressure. Provided supply pipes 63, 6
4 and return pipes 65 and 66, and is connected to the mixing head 68. Further, the supply pipes 63, 64
Is a high / low pressure switching valve 69, in front of the mixing head 68,
Return pipe 6 via detour pipes 71, 72 via 70
5, 66 are connected. On the other hand, the return pipe 65,
Heat exchangers 75 and 76 are provided between the bypass piping connection portions 73 and 74 of 66 and the return sides of the raw material tanks 61 and 62.

In the figure, reference numeral 77 is a constant temperature water tank for adjusting the temperature of each raw material tank, p ₃ is a constant temperature water pump, 79 is a cold water tank for a heat exchanger,
p ₄ is a cold water pump. In addition, the mixing head 68
Is equipped with sensors t ₁ and t ₂ for measuring the temperature of each raw material. Depending on the detected temperature, the opening and closing of electromagnetic valves b ₁ and b ₂ between each raw material tank and the constant temperature water tank and the heat exchanger It opens and closes the solenoid valve b _3, b ₄ in the cold water tank, adjusting the amount of cold water flowing to the amount and the heat exchanger side of the constant-temperature water flowing into the respective raw material tank side, so that each material temperature is constant ing. Note that t ₃ to t ₆ are sensors for measuring the temperature of each raw material supplied from each raw material tank or the temperature of each raw material returned to each raw material tank.

In this conventional high-pressure urethane injection device, first, the bypass pipe 7 is opened by the high-low pressure switching valves 69 and 70.
1, 72 are opened to prepare for discharge. Then, the raw materials are supplied from the raw material tanks 61 and 62 with the supply pipes 63 and 64, respectively.
Pumped to. The respective raw materials pumped to the supply pipes 63 and 64 pass through the bypass pipes 71 and 72 and the return pipes 65 and 66.
To the raw material tanks 61 and 62 after being cooled by the heat exchangers 75 and 76. Then supply pipes 63 and 64 again
And is circulated through the bypass pipes 71 and 72. The cooling of each raw material by the heat exchanger is to prevent the temperature rise by absorbing the heat generated by compression of each raw material and the heat generated by friction during circulation.

When the raw material temperature, viscosity, etc. are stabilized by continuing the raw material circulation for a while, the high / low pressure switching valves 69, 7 are switched.
When 0, the bypass pipes 71 and 72 are closed, and a discharge state is set. As a result, the raw materials pumped from the raw material tanks 61 and 62 are pumped to the mixing head 68 without passing through the bypass pipes 71 and 72, and the mixing head 6
After collision and mixing in 8, the mixture is discharged from the discharge port 69 of the mixing head. After the discharge is completed, the bypass pipes 71 and 72 are opened again until the next discharge, and the discharge preparation state is set.

By the way, the reaction of urethane is influenced by the raw material temperature at the time of mixing the raw materials. Therefore, in order to perform a good reaction, it is preferable to control the temperature of each raw material so that the temperature becomes a predetermined temperature immediately before the mixing.

However, in the prior art, as described above, during the circulation in the discharge preparation stage, each raw material circulates through the bypass pipes 71 and 72 and does not pass through the mixing head 68. Therefore, the temperature measurement sensors t ₁ and t ₂ of the mixing head measure the temperature of each raw material staying in the mixing head 68 at the time of the previous discharge, and the measured temperature is different from the raw material temperature immediately before mixing. . Therefore, the temperature control of each raw material tank and the cooling by the heat exchanger are performed based on the measured temperature, and it is difficult to set the temperature of each raw material at the position immediately before mixing to the predetermined temperature. Moreover, the flow rate of each raw material during the circulation is adjusted to a flow rate according to the mixing ratio at the time of discharge, but it is relatively low from the viewpoint of energy efficiency of pumping and the like, so that heat exchange in the heat exchangers 75 and 76 is performed. I was not able to show my full potential.

Therefore, in the conventional apparatus, the operator considers the influence of the outside piping on the supply pipes or the like, or the fluctuation of the circulation time due to the production amount. There has been a problem of having to adjust the temperature and valves of the tank, the cold water tank and the constant temperature water tank. In addition, troubles due to defective operation of the high / low pressure switching valve were likely to occur.

[0010]

Therefore, the present invention has been made in view of the above-mentioned points, and it is possible to easily bring each raw material to a predetermined temperature at a position immediately before mixing, and to operate the high / low pressure switching valve. The present invention provides a high-pressure urethane injection device that eliminates problems caused by defects.

[0011]

According to the present invention, raw materials that are pressure-fed from a polyol-side raw material tank and an isocyanate-side raw material tank are returned to the raw material tanks without being mixed when they are not discharged, and are circulated, while they are discharged. In a high-pressure urethane injecting device that mixes and discharges with a mixing head provided with a raw material temperature measurement sensor, in the discharge and non-discharge circulation, an outward pipe for pressure-feeding each raw material from each raw material tank to the mixing head, and during the non-discharge circulation While connecting each raw material tank to the mixing head by the return pipe for returning each raw material from the mixing head to each raw material tank, each raw material tank is connected by the auxiliary circulation pipe for pumping each raw material from each raw material tank to the return pipe. The raw material supply side of is connected in the middle of the return pipe, and a connection portion with the auxiliary circulation pipe in the return pipe Between the raw material tank according to the high-pressure urethane injection apparatus characterized in that a heat exchanger.

[0012]

In the non-discharge circulation, each raw material is pressure-fed from each raw material tank to the outward pipe at a flow rate smaller than the flow rate during discharge, that is, at a low pressure, and reaches the mixing head. The temperature of each raw material that reaches the mixing head is measured by the raw material temperature measuring sensor, and the raw material flows from the mixing head to the return pipe without being mixed with each other, passes through the heat exchanger, and then returns to each raw material tank. repeat. In addition to the raw material that goes to the mixing head, the raw material that reaches the return pipe from each raw material tank through the auxiliary circulation pipe is pumped. The raw material merges with each raw material returning from the mixing head in the return pipe, and then returns to each raw material tank via the heat exchanger. Therefore, the flow rate of each raw material passing through the heat exchanger is the sum of each raw material that has been adjusted to the mixing ratio and pumped to the outward pipe and each raw material that has been pumped to the auxiliary circulation pipe, and heat is exchanged efficiently. The flow rate is sufficient for

During the non-ejection circulation, the raw material temperature measuring sensor of the mixing head measures the temperature of each raw material passing through the mixing head. Therefore, the raw material temperature immediately before the ejection is always measured. And when discharging,
The respective raw materials that have been in the circulating state as described above are mixed with each other by the mixing head and discharged from the tip of the mixing head.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a view showing the structure of a high-pressure urethane injection device showing an embodiment of the present invention. The high-pressure urethane injection device includes a polyol-side raw material tank 11, an isocyanate-side raw material tank 12, and a mixing head 21.
The polyol-side raw material tank 11 is a tank that stores a polyol-side raw material of a polyurethane raw material, that is, a raw material in which a catalyst, a crosslinking agent, a foaming agent and the like are mixed with polyol. On the other hand, the isocyanate side raw material tank 12 is a tank for storing the isocyanate side raw material of the polyurethane raw material.
The outer peripheral portions of the raw material tanks 11 and 12 are provided with solenoid valves B ₁ and B _{2 respectively.}
Also, the raw materials in the raw material tanks 11 and 12 are maintained at a desired temperature by being connected to a constant temperature water tank 15 via a pump P ₃ and constant temperature water supplied from the constant temperature water tank 15.

The solenoid valves B ₁ and B ₂ are opened / closed by a raw material temperature measuring sensor T, which will be described later, provided on the mixing head 21.
_{1 and} T ₂ are performed corresponding to the measured values, and by opening and closing the solenoid valve, the constant temperature water tank 15 is moved to the raw material tanks 11 and 1
The amount of constant temperature water flowing to the 2 side is adjusted. Further, the set temperatures of the constant temperature water tank 15 and the cold water tank 51 are also set by the mixing head 21.
It is controlled by the raw material temperature measuring sensors T _{1 and} T ₂ provided in the.

As the mixing head 21, a known one used as a mixing head of a high-pressure urethane injection device can be used. As an example, a rod (not shown) capable of advancing and retracting is housed inside, and each raw material inlet and return opening are formed in a wall portion substantially orthogonal to the rod, at least the raw material inlets sandwiching the rod from each other. An example in which the head is formed so as to face each other and the ejection port 23 is formed at the tip of the head is given. In the mixing head 21, the raw materials that are press-fitted into the mixing head from the respective raw material inlets collide and mix with each other due to the backward movement of the rod, and are discharged from the discharge port 23 at the tip. Further, the rod moves forward to block between the raw material inflow ports, and the raw material inflow ports and the return ports communicate with each other on the rod side surface.
As a result, from the inlet of each raw material to the mixing head 21
The respective raw materials that have entered the inside flow out of the mixing head 21 through the return ports of the respective raw materials without colliding and mixing with each other.

Further, the mixing head 21 is provided with raw material temperature measuring sensors T ₁ and T _{2 such} that the sensing portions are located near the respective raw material passages in the mixing head 21. This raw material temperature measuring sensor T ₁ , T
_2, which is connected to the source tank temperature control solenoid valve B _1, B ₂ and the heat exchanger solenoid valve B ₃ to be described later, B ₄ via a control device (not shown), a raw material tank in accordance with the value of the detected temperature The temperature control solenoid valves B ₁ and B ₂ and the heat exchanger solenoid valves B ₃ and B ₄ are opened / closed, and the temperature of the constant temperature water tank 15 and the cold water tank 51 is controlled.

The raw material tanks 11 and 12 and the mixing head 21 are connected to the forward pipes 31 and 32 and the return pipes 41 and 4, respectively.
It is connected through 2. One end of each of the outward pipes 31, 32 is connected to the raw material supply side of each raw material tank 11, 12,
The other end is connected to the raw material inlet of the mixing head 21. Raw material pressure pumps P ₁ and P ₂ are provided in the outward pipes 31 and 32. 33 and 34 are inverter motors for the pumps P ₁ and P ₂ . Also T ₃ , T
₄ is each of the raw material tanks 11 and 12 and the outward piping 31, 32
It is a raw material temperature measuring sensor that measures the temperature of each raw material that is pumped to.

The return pipes 41, 42 have one end connected to the raw material return side of each raw material tank 11, 12 and the other end connected to the raw material return port of the mixing head 21. The return pipes 41 and 42 are connected to the supply side of the raw material tanks 11 and 12 via auxiliary circulation pipes 43 and 44 having auxiliary raw material pressure pumps P ₅ and P ₆ , respectively. Further, in the return pipes 41, 42, the auxiliary circulation pipe 4
Connection parts 45, 46 with 3, 44 and each raw material tank 11, 1
Heat exchangers 47 and 48 are provided between the second return side and the second return side. The heat exchangers 47, 48 are connected to a common cold water tank 51 via heat exchanger solenoid valves B ₃ , B ₄ and a pump P ₄ . The heat exchanger solenoid valves B ₃ and B ₄ are connected to the raw material temperature measuring sensors T ₁ and T _{2 of} the mixing head 21 through the control device as described above. In addition, T
₅ and T ₆ are sensors for measuring the temperature of each raw material returned to each raw material tank.

When the urethane high-pressure injection apparatus thus constructed is operated, it is first put into a non-discharge circulation state. At that time, the rod in the mixing head 21 advances so that each raw material inlet port and each raw material return port of the mixing head 21 are in communication with each other on the side surface of the rod. In this state, the raw materials having a predetermined temperature are pumped from the raw material tanks 11 and 12 to the forward pipes 31 and 32 by the raw material pressure pumps P ₁ and P ₂ , and the auxiliary circulation is performed by the auxiliary raw material pressure pumps P ₅ and P ₆ . It is pressure-fed to the pipes 43, 44. At this time, the outward pipe 31,
The flow rate ratio between the polyol-side raw material and the isocyanate-side raw material that is pressure-fed to 32 is made equal to the mixing ratio at the time of discharge that is determined according to the composition of each raw material.
It is made smaller than that at the time of ejection by 34. On the other hand, the flow rates of the polyol-side raw material and the isocyanate-side raw material that are pressure-fed to the auxiliary circulation pipes 43 and 44 are determined in consideration of efficient heat exchange by the heat exchanger.

The raw materials pumped to the outward pipes 31, 32 flow into the mixing head 21 from the raw material inlet of the mixing head 21, and flow out of the raw material return port to the outside of the mixing head 21 without being mixed with each other. Piping 4
1,42. On the other hand, each raw material pumped to the auxiliary circulation pipes 43 and 44 reaches the return pipes 41 and 42, and joins with each raw material that has returned via the mixing head 21, and then is directed to each raw material tank 11, 12. Return pipe 41,
42 is pumped. The combined raw materials are returned to the raw material tanks 11 and 12 after being cooled to a predetermined temperature through intermediate heat exchangers 47 and 48, and thereafter this circulation is repeated. At this time, the combined raw materials are heated by the heat exchangers 47, 48.
Since it passes through, the flow rate becomes sufficient for heat exchange, and each raw material is efficiently cooled.

During the non-ejection circulation, the temperature of each raw material passing through the mixing head 21 is constantly measured by the raw material temperature measuring sensors T ₁ and T ₂ provided in the mixing head 21. The raw material tank temperature adjusting solenoid valves B ₁ and B ₂ and the heat exchanger solenoid valves B ₃ and B ₄ are opened and closed according to the difference between the measured temperature and the preset mixed discharge temperature of the raw materials, and mixing is performed. The temperature of each raw material passing through the head 21 is set to the set mixed discharge temperature.

Incidentally, the comparison between the measured temperature and the set temperature,
The opening / closing command of the raw material tank temperature adjusting solenoid valves B ₁ and B ₂ and the heat exchanger solenoid valves B ₃ and B ₄ may be performed by the control device, or the raw material temperature measuring sensor T may be provided without providing the control device. _The operator may open and close the solenoid valves B ₁ , ... In accordance with the measured values of ₁ and T ₂ .

Next, the raw materials are mixed and discharged. The mixed discharge is performed by raising the pressure of the raw material pressure pumps P ₁ and P ₂ by the inverter motors 33 and 34, and retracting the rod in the mixing head 21. As a result, the raw material inlets of the mixing head 21 directly face each other, and the high-pressure raw materials pumped into the mixing head 21 from the raw material inlet of the mixing head 21 through the forward pipes 31 and 32 collide and mix with each other. It is ejected from the ejection port 23 of the mixing head 21. During this time, each raw material circulates through the auxiliary circulation pipes 43 and 44. Further, the raw material temperature measuring sensors T ₁ and T ₂ measure the raw material temperatures in the mixing head 21, and the temperature of each raw material is adjusted according to the measured temperature. After the end of the discharge, the non-discharge circulation state is set again to prepare for the next discharge.

[0025]

As shown and described above, according to the present invention, since each raw material constantly passes through the mixing head, the temperature of each raw material at the position immediately before the mixed discharge is measured by the raw material temperature measuring sensor provided in the mixing head. Can be measured. Therefore, if the temperature of each raw material is adjusted based on the measured temperature, the temperature of each raw material at the position immediately before mixing can be extremely easily set to an appropriate value.

Moreover, since the raw materials circulated through the mixing head and the raw materials circulated through the auxiliary circulation pipe are combined and then passed through the heat exchanger, the flow rate of the raw materials through the heat exchanger is The amount is sufficient for efficient heat exchange, and the raw material temperature is efficiently adjusted. Further, since the high / low pressure switching valve is not required, there is no problem caused by the malfunction of the high / low pressure switching valve.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of a high-pressure urethane injection device showing an embodiment of the present invention.

FIG. 2 is a view showing a structure of a conventional high-pressure urethane injection device.

[Explanation of symbols]

11, 12 Raw material tank 21 Mixing head 31, 32 Forward piping 41, 42 Return piping 43, 44 Auxiliary circulation piping 47, 48 Heat exchanger T ₁ , T ₂ Raw material temperature measuring sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 105: 04

Claims (1)

[Claims] 1. A mixing system in which each raw material fed under pressure from a polyol-side raw material tank and an isocyanate-side raw material tank is returned to the respective raw material tanks and circulated without being mixed during non-discharge, and a raw material temperature measuring sensor is provided during the other discharge. In a high-pressure urethane injecting device that mixes and discharges with a head, in the discharge and non-discharge circulation, a forward pipe for pressure-feeding each raw material from each raw material tank to the mixing head, and during the non-discharge circulation from the mixing head to each raw material tank The raw material tank is connected to the mixing head by the return pipe for returning the raw material, and the raw material supply side of each raw material tank is connected by the auxiliary circulation pipe for pumping the raw material from the raw material tank to the return pipe. Connected on the way, and between the raw material tank and the connection part with the auxiliary circulation pipe in the return pipe Pressure urethane injection apparatus characterized in that a exchanger.