Daily chemical pump head is a kind of packaging material, widely used in cosmetics packaging materials. When using the pump head, the material body will not be exposed, and the human body will not touch the material body in the packaging container. Different pump heads can be selected according to the characteristics of the material body to control the discharge volume and discharge effect, and the material can be discharged by pressing. Based on the advantages of sanitation, convenience and diversity, pump heads are widely used in cosmetics packaging materials. It is particularly important to control the quality of pump head.
This paper mainly discusses the detection methods of functional items of lotion pump head except appearance and size items. Let's look at the classification and principle of pump head first.
1、 Classification of pump head
1. The pump head can be divided into screw pump head, cartridge pump head, left and right locking pump head, hand-held pump head (spray gun), direct-pressure outer cover pump head and left and right locking outer cover pump head according to the opening mode of head cap (pressure head). The manual button pump head is mainly used for detergent products, such as degreasing and glass cleaning. The above classification is based on Bian Xiao's own understanding.
2. Pump head can be divided into lotion pump head, foam pump head, vacuum pump head, spray pump head (nozzle), aerosol pump head, etc.
2、 Principle of pump head
1. Principle of lotion pump head
Lotion pump head is a small reciprocating piston pump. Manually press the pressure head of the pump head, and the spring in the reservoir is compressed. In the process of compressing the spring, open the exhaust hole of the pump core. When the piston slides, the air in the pump core is discharged through the exhaust hole. Press back and forth to remove the air from the pump core.
When the pressure head of the pump head is released, the spring will rebound due to the pressure loss and close the discharge port. At this time, the liquid storage chamber is in the vacuum suction state, and the glass (steel) beads are sucked up, and the materials in the bottle are sucked into the liquid storage chamber through the suction tube. Press the pump head back and forth for several times to suck the material, and store the material in the pump core until all the materials are stored. Press the pump head again, and the material will be directly pumped out from the pump nozzle through the discharge port.
2. Principle of vacuum pump head
The vacuum pump head has no suction pipe. There is a small hole under the bottle to match the vacuum pump head. There is a piston in the bottle. A small hole is left at the bottom of the bottle to connect the bottom of the piston with the atmosphere. When the vacuum pump head is pressed, the air in the bottle cavity will be discharged and the pressure will be reduced. Due to the difference in internal and external pressure, the piston in the bottle will move upward, pushing the material in the bottle upward. When the material is in contact with the suction inlet of the pump head, the material is extracted from the pump nozzle by pressing the pressure head back and forth.
3. Principle of foam pump head
The foam pump head is mainly used for hand sanitizer, facial cleanser, shampoo and shower gel, especially suitable for children. The internal structure of foam pump head is complex.
After the material in the bottle passes through the mesh inside the foam pump head, the material is wrapped in the air and foamed by the small mesh, thus pressing out the foam.
4. Principle of spray pump head (nozzle)
The spray pump head mainly adopts Bernhard principle, with fast fluid flow rate, low pressure, slow flow rate and high pressure. This is also the principle of playing the so-called "banana ball" when playing football penalty.
By pressing the nozzle, due to the pressure difference between the inside and outside of the bottle, the material in the bottle will be sprayed out. The high-speed flowing material will drive the gas flow near the nozzle mouth, so that the gas velocity near the nozzle mouth will increase and the pressure will decrease, thus forming a local negative pressure zone, so that the surrounding air will be mixed into the liquid, forming a gas-liquid mixture, making the material diffuse in the air, with atomization effect, and forming small particles of air suspension.
5. Principle of aerosol pump
The aerosol product in one package is packaged in a pressure-resistant container and contains propellant. Generally, the pressure in the aerosol tank is higher than the external atmospheric pressure. When the pressure head is pressed down, the valve channel opens, and the pressure in the aerosol tank causes the substances in the tank to rise through the suction pipe and spray out from the nozzle. When the material passes through the narrow nozzle at high speed, liquid droplets are formed due to the rapid evaporation of the propellant. Change the valve structure and spray foam. For example, shaving foam.
3、 Several factors affecting the pump efficiency of lotion pump head?
1. Sealing performance of glass (steel) beads under the spring: the sealing performance here is related to the upward scouring force of the liquid in the spring cavity. If the sealing performance is not good, when the pressure head of the pump is under pressure, some materials will leak into the bottle, thus affecting the pumping effect.
2. Sealing performance of the sealing ring at the upper end of the valve body: if there is leakage here, when the pressure head of the pump head is released, the force of the material sucked into the spring cavity will be reduced.