This article mainly discusses the testing methods of the functional items of the lotion pump in addition to the appearance and size items. First look at the classification, principle and scope of application of the plastic pump.
Classification Of Plastic Pumps
1. The plastic pump can be divided into Screw Plastic Pump, cassette plastic pump, Left And Right Lock Plastic Pump, hand buckle plastic pump (Trigger Sprayer), direct push plastic pump with outer cover and Equipped with an outer cover to lock the plastic pump left and right. The hand button plastic pump is mainly used for detergent products, such as degreasing and glass cleaning products. The above classification is divided by the editor according to my own understanding.
2. According to the function, the plastic pump can be divided into lotion plastic pump, foam plastic pump, airless plastic pump, spray plastic pump (plastic sprayer), aerosol pump (aerosol sprayer) and so on.
The Principle Of The Plastic Pump
1. Principle of plastic lotion pump
A lotion pump is a small reciprocating piston pump. Manually press the pressure head of the plastic pump, and the spring in the liquid storage chamber is compressed. In the process of compressing the spring, the discharge hole of the pump core is opened, and the air in the pump core is discharged through the discharge hole when the piston slides down. Press back and forth to expel the air in the pump core.
When the plastic pump is released and pressed, the spring will rebound due to the loss of pressure, and the discharge port will be closed. At this time, the liquid storage chamber will form a vacuum suction state, and the glass (steel) beads will be sucked up, and the material in the bottle will be sucked into the storage through the suction tube. inside the liquid chamber. Reciprocatingly press the pump head to store the material in the pump core through multiple suctions until the material is fully stored. Press the plastic pump again, and the material will be directly pumped out from the pump nozzle through the discharge hole.
2. Principle of Airless Pump
The airless pump does not have a suction tube. There will be a small hole under the bottle that matches the airless pump. There is a piston in the bottle. A small hole is left at the bottom of the bottle to communicate with the atmosphere at the bottom of the piston. When the airless pump is pressed, the air in the bottle cavity is discharged and the pressure becomes smaller. The piston in the bottle will move upward due to the pressure difference inside and outside, pushing the material in the bottle to move up. When the material body is in contact with the suction port of the plastic pump, the material body will be pumped out from the pump nozzle by reciprocatingly pressing the pressure head.
3. Foam Pump Principle ( Foaming Soap Dispenser )
Foaming Soap Dispensers are mainly used in products such as hand sanitizer, cleansing water, shampoo and shower gel, especially for children's products. The internal structure of the Foaming Soap Dispenser is relatively complicated.
After the material body in the bottle passes through the mesh inside the Foaming Soap Dispenser, the material body is wrapped in air and is beaten into bubbles by the fine mesh, so what is pressed out is foam.
4. Principle of Spray Pump (Mist Sprayer)
The Mist Sprayer mainly uses Bernoulli's principle, the fluid flow rate is fast and the pressure is low, and the flow rate is slow and the pressure is strong. This is also the principle of kicking the so-called "banana ball" when kicking a football penalty kick.
By pressing the nozzle, the material in the bottle is ejected due to the pressure difference between the inside and outside of the bottle. The high-speed flowing material will drive the gas flow near the small hole of the nozzle, so that the speed of the gas near the small hole of the nozzle becomes larger and the pressure becomes smaller, forming a local Negative pressure zone, so that the surrounding air is mixed into the liquid to form a gas-liquid mixture, so that the material can be atomized and diffused in the air to form small particles of air suspension.
5. Aerosol Pump Principle
One-pack aerosol products are contained in a pressure-resistant container containing a propellant. Usually the pressure in the aerosol can is higher than the outside atmospheric pressure. When the pressure head is pressed, the valve channel is opened, and the pressure in the aerosol can causes the material in the can to rise through the straw and be sprayed out from the nozzle. When the material body passes through the narrow nozzle at high speed, mist droplets are formed due to the rapid vaporization of the propellant. Changing the valve structure can also spray foam, etc. Like shaving foam.
6. Several Factors Affecting The Effect Of Lotion Pump Materials
01). The tightness of the glass (steel) ball under the spring: the tightness here is related to the strength of the liquid in the spring chamber rushing upwards. If the tightness is not good, when the plastic pump is pressed, there will be some material The body leaks into the bottle, which affects the pumping effect.
02). The tightness of the sealing ring at the upper end of the valve body: if there is leakage here, when the pressure head of the plastic pump is loosened, the force of the material body being sucked into the spring chamber will be reduced.
The Scope Of Application Of The Plastic Pump
The plastic pump is mainly used for water, milk, shampoo, shower gel and other materials with good fluidity. Different types of plastic pumps should be selected according to the characteristics of the material body and the use effect to be achieved. Slightly thicker materials such as hair conditioner are also available with a plastic pump. However, it is not suitable to use the plastic pump for thicker materials, and there will be either the pump does not discharge, or the material is interrupted during the pumping process.
For thicker materials, it is necessary to fill the material and do a pump test before confirming the use of the plastic pump. When using the plastic pump to pump liquid oil products, although not all of them will leak, there is a greater probability of individual leaks.
For the Foaming Soap Dispenser, what is pumped out is foam, no need to soak in water to rub and foam, the dosage is less, and it is easy to use. The material in the Foaming Soap Dispenser must be liquid, and the material must be very thin and not thick, otherwise the mesh will be blocked and the material will not be pressed out. The bottle with Foaming Soap Dispenser can only hold liquid but not lotion, and the fine mesh inside the plastic pump must not be missing, otherwise the foam will not be pressed.
The sealing of the plastic pump is not good, such as water leakage, usually in three places, namely the thread, the pump core and the pump nozzle. For water leakage at the screw teeth, it can basically be solved by changing the thickness of the gasket inside the plastic pump cover. For water leakage at the pump core and pump nozzle, there is a problem with the structure or production of the plastic pump itself.
Number of Pumps
In layman's terms, the number of pumping of the plastic pump is how many times the plastic pump is pressed with the maximum stroke of the plastic pump to discharge the material. This indicator is more important. If the plastic pump is pressed for many times but does not discharge or has to be pressed many times before it discharges, such a plastic pump is unqualified. If a product with such a plastic pump leaves the factory, it will be returned.
When testing the number of pumps, pour the actual filling material into the bottle, and after screwing the plastic pump, unscrew the pressure head of the plastic pump or remove the clip of the plastic pump, etc. to make the plastic pump in a pressable state. Press the plastic pump until it can no longer be pressed down (that is, the maximum stroke of the plastic pump) and let go until the plastic pump pops up completely. This is a complete pumping process. Repeat and continue to press the pump until it starts to pump out. Count the number of times the plastic pump is pressed.
Usually, the number of pumps of water-based products does not exceed 5 times. Other slightly thicker products do not exceed 10 times. Generally, the water test of the plastic pump is basically 2-3 times of water discharge.
I have experienced it in the early days. During the production process, it was found that the plastic pump needs to be pressed dozens of times before the material is discharged. Later, there is no way to press all the produced products until the plastic pump is almost discharged for rework.
According to the characteristics of the product used, select the plastic pump with the appropriate pump output. For example, shampoo, shower gel and the like are used in a large amount at one time, so a plastic pump with a large pumping volume should be selected. For products such as water and milk, a plastic pump with a slightly smaller pumping volume should be selected. The pump output of the plastic pump should be uniform and stable. The deviation of the pump output is determined according to the needs of use and the characteristics of the plastic pump.
When testing the pump output of the plastic pump, pour the actual filling material into the bottle. After screwing the plastic pump, unscrew the pressure head of the plastic pump or remove the clamp of the plastic pump, etc. to make the plastic pump in a depressible state. Press the plastic pump repeatedly with appropriate force until the plastic pumps out the material, and then press it several times continuously until the plastic pump discharges the material smoothly.
Put the bottle with the plastic pump filled with the material body on the electronic balance, weigh and peel it, and then use an appropriate force to press the plastic pump to the maximum stroke. After the pump discharges the material, put it on the electronic balance and weigh it. For one pumping volume.
Repeatedly measure 3 pumping volumes in this way, press the plastic pump 10 times continuously regardless of weight, then measure 3 pumping volumes continuously according to the above method, press the plastic pump 10 times continuously regardless of weight, and finally measure continuously according to the above method Out of 4 pumps, calculate the average value of 10 pumps. Simultaneously measure 4 plastic pumps according to the aforementioned method, and take the average value of the pump output as the actual pump output of the plastic pump.
Compatibility Of Plastic Pump And Bottle
For packaging materials with screw-fitted bottles, when the plastic pump is rotated, the plastic pump and the bottle should rotate smoothly without idling, detached or slipped teeth. After tightening the plastic pump, the plastic pump should not be skewed or loose, and the distance between the lower end of the plastic pump and the bottle shoulder (commonly known as "hanging feet") should not be too large, usually no more than 1mm, which is more beautiful. How appropriate is determined according to the actual situation of the product. The plastic pump equipped with an outer cover should be tight and fit after the outer cover is covered.
For packaging materials that use a bayonet fit between the plastic pump and the bottle, such as some airless bottles, a capping machine is used to press the outer cover of the airless pump to combine the airless pump and the bottle body. There should be no gap between the plastic pump and the bottle body.
Plastic Pump Dip tube Port and Length
The port on the side where the dip tube of the plastic pump contacts the bottom of the bottle should not be made flat, otherwise there will be problems with the pump not feeding or cutting off. Usually the suction tubes provided by the plastic pump factory have gaps at both ends of the dip tubes. There are special tools for cutting straws. If you feel that the straw is too long and you want to cut it by yourself without special tools, use scissors to cut the end of the straw into a bevel.
Usually the length of the dip tube is the ideal length after the dip tube is inserted into the plastic pump and inserted tightly, and the length of the dip tube against the bottom of the bottle without bending after the plastic pump is tightened is the ideal length. The bottom of the plastic pump can be placed on the outside of the bottle where the bottom of the plastic pump is normally tightened, and the distance between the end of the straw and the bottom of the bottle can be used to judge whether the length of the straw is appropriate. It should be noted that some bottle bottoms are convex inward. The dip tube of the plastic pump should not be too long or too short. The dip tube of the plastic pump is too long, and the end of the thinner suction tube is easy to bend up, resulting in incomplete pumping. For thicker dip tubes, the plastic pump resistance is large and easy to discount, which also affects the pumping material. Needless to say, the straw is too short, the pump material is not thorough.
Pump Head Resilience (Rebound Time)
Tighten the plastic pump on the matching bottle so that the plastic pump pressure head is in a pressable state. Use an appropriate force to press the pressure head until it can no longer be pressed down (maximum stroke) and then immediately count the time after letting go. The time required for the pressure head to bounce back completely is the rebound time of the plastic pump. Usually the rebound time of the plastic pump is no more than 3 seconds.
Fill the bottle into the actual filling and measuring material, and after screwing the plastic pump, the plastic pump is facing upwards, and the bottom of the bottle is facing downwards, 1.2m from the ground, and freely falls onto the flat floor tiles. There should be no leakage, and the pump head and bottle should not be loose, scattered, damaged or affect the sealing and use effect.
Heat And Cold Resistance Test
Fill the bottle into the actual filling and measuring material, screw the plastic pump, and put it in a (48±1) ℃ incubator and (-15±2) ℃ refrigerator for 24 hours (the specific temperature setting value can be determined according to needs) ), after returning to room temperature, the plastic pump should be able to use normally. It can also be tested by heating and cooling cycles.
The fatigue test is to test whether the plastic pump can be used normally after being pressed for many times. I have seen that the plastic pump factory needs to press the plastic pump 1000 times during the fatigue test. Usually, you can fill the bottle according to the actual filling amount, press the plastic pump to pump the material in the bottle to the bottom of the bottle, and check whether the plastic pump is in normal use during the pumping process.
The airless bottle fatigue test can also be called the suction test. After filling the bottle according to the actual filling amount, press the plastic pump until it can no longer pump out the material. See if there is a significant difference between the pump output airless and the actual filling volume.
Other Test Items
1. Mechanical test items
The mechanical test items of the plastic pump mainly include the tightening torque between the plastic pump and the bottle, the unscrewing torque, the sliding tooth torque and the unscrewing torque of the plastic pump pressure head, etc., which can be tested with a torque meter. In practice, there was a problem that the pressure head of the screw plastic pumpd could not be unscrewed. Later, a gasket was added to the plastic pump to solve it.
The pull-off force test items mainly include the pull-off force of the pump cover, the pull-off force of the pressure head, the pull-off force of the pump core, the pull-off force of the pump cover and the pump sleeve, etc., which can be tested with a tension meter.
2. Compatibility test items
The main consideration is whether the plastic pump will be affected when the material is stored for a long time. The plastic pump is usually tested for heat resistance and cold resistance under the condition of filling. The duration is three months. In the meantime, the results can be viewed at intervals of three days, one week, half a month, one month, two months, and three months. A common question is whether the spring of the plastic pump will rust. If the balls in the plastic pump are made of steel balls, the rust of the steel balls should also be considered.
Supplementary Instructions for Pump Head Testing
1. An important item in the Foaming Soap Dispenser test is to consider that the pumped foam must be dense and delicate.
2. When testing the airless bottle, it is necessary to test the friction between the inner wall of the bottle and the piston.
3. One of the core inspection items of the mist sprayer is the atomization effect. The spray should be continuous and uniform without obvious droplets. In addition, the spray angle and spray distance need to be tested, referring to 15 national standard tests.
4. The plastic pump factory will test the suction of the plastic pump when testing the lotion pump.
Aerosol Pump Test Method
The test methods for some main indicators of the aerosol pump can refer to the corresponding methods in the following national standards:
GB/T 14449—2017 Test methods for aerosol products
There are relatively many test items mentioned above, and the core items should be tested first in the actual test. For the plastic pump used in cosmetics, more attention should be paid to its influence on use. For some test items, if the requirements are not high, such as mechanical test items, etc., qualitative judgments can also be made based on the effect during use. In addition, the qualification standards for the pump head test items are only given the general standards, which can be determined according to their own requirements during the actual test
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