For convenient using or some special reasons, hand need hold the sprayer in an upside-down position to spray. This siuation often happens for mosquito and kitchen sprays. The pharmaceutical products rarely use this spraying position.
The hand holds the sprayer in an upside-down position to spray. This type sprayer is called as upside-down sprayer or 360° sprayer
Only non-ball valve can stably spray out liquid when in an upside-down position because the finger can completely control the valve on or off status. The ball valve can also spray out liquid in an upside-down position but the stability is lower, because the valve switching off mode is less controllable.
Another point, to allow suction of liquid when the bottle is in whichever upside-down or upside-up (normal) position, a special valve is mounted between the pump and the diptube. The non-ball valve pump without such suction valve can spray only 2 to 3 times and then no more liquid will go out.
Although the sprayer can spray in upside-down position, the leakage can not be avoided. When spraying, a small channel balancing the gas pressure inside and outside bottle opens and bubbles can be found to go into the bottle. Throught the same channel, the liquid can also possibly go out to cause leakage. It is not be found that every spray will leak, but the leakage does happen sometimes. No effective method can control it. This leaking problem limits the wide range application of upside-down sprayers.
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