Types of dispensing valves and application characteristics

The dispensing valve is divided into one-component dispensing valve and two-component dispensing valve according to the type of glue processed, contact type and non-contact type according to the type of dispensing method, and high-precision dispensing valve and low-precision dispensing valve according to the dispensing accuracy requirements.

1. One-component valve body: This type of valve body only handles one-component glue, and most of the valve bodies on the market are currently used. We need to pay attention to the chemical and physical properties of the glue to choose the appropriate one-component valve body, such as the more corrosive glue, we need to choose a one-component valve body with corrosion-resistant contact materials.

2. Two-component valve body: This type of valve body to process AB component glue, need to go through the mixing pipe for AB glue mixing, there are currently three ways of the principle of the valve: one is a metering type of two-component, first inject A and B glue into the two cylinder blocks, the volume ratio of the two cylinder blocks is constant, and then seal the cylinder block and push it out with a piston. The second type of rubber drum is directly installed with a mixer, and the rubber drum is directly pushed by the server pusher. The third is to use the progressive valve to distribute A and B glue.

3. Contact dispensing valve: the needle part of the contact dispensing valve needs to keep a relatively close distance from the dispensing surface, for products with uneven dispensing planes, this valve body is easy to scrape the needle, and this distance has a great impact on glue, this valve body also has a drawing situation, it needs to have a certain suction back function. Contact dispensing valves have relatively low dispensing efficiency, but they have good stability for handling high-viscosity glues.

4. Non-contact dispensing valve: Because the non-contact type is a jet dispensing, it relies on the impact of the firing pin and nozzle to produce the glue, and it is easier to block the nozzle for high-viscosity glue, so this type of valve body is suitable for medium and low viscosity glue. Because the glue is sprayed out, the distance between the dispensing needle of the non-contact dispensing valve and the dispensing plane can be relatively far, and the slight change of distance has little effect on the dispensing, and the non-contact dispensing valve does not require high flatness of the dispensing plane. In addition, non-contact dispensing valves have the highest working efficiency.

5. High-precision dispensing valve: This type of valve body is less affected by external factors, such as air pressure, temperature, humidity, its stability is relatively good, CPK is relatively high, the price is relatively expensive, the current high-end dispensing valve in the accuracy is the piezoelectric ceramic jet valve and progressive cavity valve is the best, this type of valve body consumables are relatively large, the maintenance cost is also relatively high, and the disassembly and cleaning are relatively troublesome. It is generally used in occasions where accuracy and stability are required.

6. Low-precision dispensing valve: This type of valve body is easily affected by various external factors, and the dispensing stability is average, making it a relatively economical choice for process requirements without CPK requirements. The low-precision dispensing valve is mainly the air pressure switch valve, and the glue dispensing mainly relies on the gas pressure push, and the stability of the air pressure has a great impact on the glue.