1.High pressure mixing gun head(FPL) 

The most important part of the high-pressure foaming machine is the mixing gun head. The task of the gun head is to evenly mix the two raw materials. This advanced FPL gun head was invented in Europe and adopted by many countries. It has international authority. This kind of gun head is used in this equipment. Its basic principles and characteristics are as follows:

1.1 Mixing function 

The gun head is designed with two gun rods (pistons), in which the small piston controls a small mixing chamber and the nozzle of two raw materials. When the small piston rod is opened, the two raw materials flow through the nozzle under the action of high-pressure pump, and 10-20Mpa is generated due to the nozzle resistance The high pressure makes the two raw materials collide and mix in a small mixing chamber at high speed, and vaporizes instantaneously to produce high-quality mixture, which enters into another pressure reducing chamber controlled by piston gun rod. When the mixture enters the mold cavity, it splashes because of the pressure release. At this time, the mold does not bear much pressure.

1.2 Self cleaning function

After the injection, the small piston is pushed into the mixing chamber automatically by the electrical and hydraulic system of the equipment to isolate the two kinds of raw materials completely, and push the residual foaming material out of the mixing chamber to complete the self-cleaning function of the gun head, without using cleaning agent to clean the gun head, so as to ensure continuous injection work.

1.3 Metering function

There is a timer with a precision of 0.01 seconds in the PLC to control the injection time of the gun head. When the gun head is working, due to the high timing accuracy of the time timer, the injection amount can be accurately guaranteed by adjusting the injection time for different products. 

1.4 Manufacture of high pressure mixing gun head

Due to the use of three coordinate high-precision grinder and five coordinate four linkage horizontal machining center as the final processing guarantee means, this advanced FPL hybrid gun head has a processing accuracy less than 0.002mm, which is not achieved by conventional processing methods. The gun head parts made of special steel after special heat treatment have high surface hardness and excellent wear resistance. Therefore, the mixing gun head made by the above technology has high precision and service life. 

2. Station setting 

There are two groups of 16 timer controlled timing stations in each group of injection gun heads on the standard high-pressure foaming machine. Each station can adjust the injection time arbitrarily within 0.o1-99.99 seconds, and then control the injection amount. In this way, even if it is a small batch or a variety of different injection requirements can also be timely and convenient to meet, can infinitely adjust the set injection volume.

3. Lubrication system 

The lubrication system is an auxiliary facility. Since the black material (isocyanate) in the production of polyurethane is sensitive to water and temperature in the air, it reacts when it contacts with air and water, and gradually forms a hard block. In this way, the isolation from air and water in the black material system becomes very important and difficult. Especially, the rubber seal in contact with the black material will often be damaged, and the lubrication system will be convenient It can protect the rubber seal of the black material system, isolate the black material from the air, prolong the service life of the seal, and ensure that the black material does not solidify, thus improving the reliability of the whole machine.

4. Electric feeding device

The electric feeding device is an auxiliary facility specially designed for the convenience of single machine production. The device can automatically feed two storage tanks without manual feeding. It has the characteristics of high efficiency, no waste and clean site.

5. Ingredient ratio adjustment

 The mixing and testing of the two material ratios of the high-pressure foaming machine are controlled by the high-pressure variable pump and the separately set proportional gun head. The high-pressure variable pump has the performance of high-precision variable flow. The output flow can be easily adjusted by using the manual wheel. The variable range can be arbitrarily set within the range of 1 / 3 and 3 / 1 on the premise of meeting the injection requirements. The high pressure produced can reach 25MPa. Because the high pressure variable displacement pump is a kind of inclined shaft plug variable displacement pump (international common structure), it has high volumetric efficiency and precision. The proportional gun head is specially used to detect the ratio of the two raw materials, which is consistent with the injection gun head synchronously. At this time, the gun head does not inject material but synchronously measures the weight and proportion of the two raw materials that have passed through the injection gun head in unit time, so as to determine the proportion passing through the gun head, and adjust the required proportion and flow rate through the variable pump hand wheel, so as to serve for the final determination of reasonable process parameters.

6. Storage and temperature control of raw materials for high pressure foaming machine

There are two 300 L heat preservation storage tanks on the high-pressure foaming machine. Each storage tank has a set of feeding device, which can electrically input black and white materials in raw materials into the storage tank for storage as required. The temperature control of the two materials depends on two heat exchangers for heating and cooling. The circulating cold and hot water used by the heat exchanger is provided by a special cold and hot water unit. The constant temperature precision value is set at plus or minus 2 degrees, and is automatically controlled by two temperature controllers connected with the host computer. This device ensures the continuity of the foaming machine and the accuracy of the foaming temperature control, thus ensuring the production efficiency and quality stability of the foaming machine.