In the Trigger Sprayer(KEXON) mechanism above, the one-way valve between the pump and the nozzle is a sort of cup, which fits over the end of the barrel. On the upstroke, the inward pressure from the pump pulls the cup against the barrel, so air can't flow in through the nozzle. On the downstroke, the fluid pushing out lifts the cup off the barrel slightly and flows on through the nozzle. Without this second one-way valve, the pump system wouldn't be able to draw fluid up from the reservoir because there would be no suction (no drop in air pressure). The upstroke wouldn't lower the air pressure in the pump; it would only draw in more air to maintain that pressure.
This valve also works as a shut-off system. When you screw the nozzle piece in, it pushes the valve cup tightly against the barrel, so you can't force any liquid out. When you loosen the nozzle piece, there is enough room for the valve cup to move back and forth.
Ningbo KeXon Plastic Co., Ltd. is a comprehensive plastic packaging enterprise integrating design, production, and sales. We own a factory (Yuyao KeXon Sprayer Factory), and its plant area is over 6,000 square meters, with more than 20 years of production experience in various types of daily packaging. The company can professionally produce all kinds of foam pumps, plastic caps, daily and medicinal plastic bottles, as well as all kinds of trigger sprayers, lotion pumps, perfume sprayers, cream jar and other products.
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