Polyurethane foam molding equipment
DATE：2022/4/15 8:34:48 / READ： / SOURCE：This station
Polyurethane foam molding equipment
The polyurethane foam molding equipment is simpler than the injection molding and extrusion molding equipment, mainly including storage of raw materials, conveying and metering devices, mixing devices, bulk foam molding and setting devices, cutting and coiling devices, molding foaming devices, and spray guns. Antirust paper coating equipment www.handern.com com1、 Storage, transportation and metering device of raw materials
The main equipment of foam plastic casting, storage, transportation and metering devices is the group of various awards, battalions and various electrical appliances, etc. the low pressure mixing process schematic I- raw material storage tank; 2 - low pressure metering pump: 3 - filter; 4 - safety valve; 5 - pressure gauge;
6. Open reading at the same time; 7 - low pressure mixing head; 8. Air; 9. The general structure of a solvent shaped raw material storage tank is shown in Figure 7-29. The stainless steel sleeve is used to solve the anti-corrosion problem. The storage tank is also equipped with stirring and jacket heating constant temperature devices. Some storage tanks are also reaction kettles. The purpose of mixing is to make the storage liquid mix evenly and prevent the stratification of materials with different relative densities and uneven temperature distribution. The heating constant temperature device is to keep the material temperature constant, make the foaming process have good repeatability and maintain the stability of production quality. The temperature control accuracy of the temperature regulator is required to be ≤± 1 ℃. Antirust paper coating equipment www.handern com
The metering pump is also a key part of the foaming equipment, which directly affects the accuracy and stability of each component in the raw materials according to the formula. The metering pump is driven by the motor, and the flow of the metering pump can be adjusted by directly using the variable pump, or using the thyristor to control the speed change of the motor, or through the combination of stepless speed converter and motor, so that the flow of the metering pump can be adjusted steplessly, and the measurement error is required to be ≤ 1%. For materials with high viscosity and poor fluidity, such as polyester and prepolymer, gear metering pump or ring 1-raw material storage tank are usually used; 2 - filter; 3 - metering pump; 4 - pressure gauge; 5 - Safety and moistening: 6 a syringe; 7. A mixing head (capable of self-cleaning); 8. There are two types of metering pumps for the low viscosity piston pump. One is suitable for the high-pressure mixing head. A Bosch diesel nozzle pump is commonly used. The flow can be controlled by adjusting the stroke of the piston or the speed of the motor. The adjustment range is 1 ~ 10, and the outlet pressure can reach 6.9 ~ 10.3MPA; The other is suitable for low-pressure mixing head, which is commonly used as annular piston pump, and its flow can be realized by adjusting the gap between rings. These two types of metering pumps can use thyristor variable speed motor or mechanical stepless transmission to adjust the speed and control the flow of materials. It is also used in the material conveying system. Antirust paper coating equipment www.handern.com com
2、 Mixing head
Mixing head is an important equipment for foam material casting. The strip components of raw materials are foamed and formed by the metering forming and shaping device. After the pump, it is continuously pressed into the mixing head for mixing, and the mixed material flows out directly into the starting and running mixing head. According to the different mixing pressure, it can be divided into high-pressure mixing head and low-pressure mixing head. At present, low-pressure mixing head is widely used in China. Antirust paper coating equipment www.handern.com com
1. The low-pressure mixing head has wide adaptability and can be applied to both high tray viscosity and low viscosity raw materials. The disadvantage is troublesome cleaning and more loss of raw materials. Its structural diagram is shown in Figure 7-30, which is mainly composed of mixing power equipment, agitator and mixing head nozzle agitator. Each barrel and component of raw materials are injected from the upper part of the mixing chamber, and then sprayed from the nozzle after being stirred and mixed evenly at high speed by the mixer. They are directly injected into the foam forming device for foam forming and shaping. The structural properties of each component of the mixing head are as follows. Antirust paper coating equipment www.handern.com com
(1) Mixing power equipment
The power source generally comes from the motor. The motor drives the mixing head nozzle through the pagoda plate and belt pulley, which can be adjusted from 2000r / min to 6000t / agitator shaft. Generally, the speed of the agitator
(2) Agitator is the key part to determine the uniformity of mixing. According to the schematic diagram of the mixing head of the foaming machine, the shear strength during mixing can be divided into two categories: one is the low shear type, the multiple straight knife agitators shown in Fig. 7-31 (1) and 2) needle and paddle mixers shown in Fig. 7-31 (1) and 2). It forms a mixing system with material Jane. This kind of low shear mixing system is suitable for cooperating with low-pressure metering system, but it is not easy to clean. It is often used in large foam molding and foam molding. The other type of agitator is of high shear type, which is composed of a round simplified body and a spiral agitator [see Fig. 7-31 (3). The matching room between the agitator and the material is small, usually A15 ~ 0.76mm. This type of agitator has less material storage and is easy to be cleaned with compressed air, which can be used for model forming and foaming process. However, the high shear type agitator produces large back pressure and often needs to be used in combination with the high-pressure metering system.
Author：admin