Function test should be the main section in whole sample test. The scores on function test determine to a great extent if the sampled trigger sprayer can bring good product performance and user experience.
full fill bottle with fluid, count how many times of squeezes is used until the first spraying come out. This test somehow reflects the airtightness in piston and cylinder.
operate at least 30 times squeezes, spraying the fluid into a wide opening measuring cup. Then measure the total volume of fluid, divide corresponding squeeze times to get output.
While a certain spray angle is needed, operate this test. Place trigger sprayer’s nozzle end at a certain distance from target surface(normally in 20cm), then squeeze trigger and measure the diameter of the wet area on surface. This should be operated indoor and spray fromabove down to minimize impact from gas flow and gravity.
press trigger at least 30 times to check if leakage occurs on nozzle end and piston, test on both spray and stream patterns.
if trigger spray pump comes with foam nozzle, foaming test should be operated and check how long the foam can cling on target surface.
normally air venting hole is visible under the gasket seal. Air venting hole prevent bottle from collapsible after multiple squeeze. So don’t forget to check if your test bottle is collapsed after multiple squeezes.
This could be the hardest part of test at customer’s end, as it may take thousands of squeeze and humans’ hand can’t bear for that. If not applicable on your end, ask supplier to proceed this test and submit test report. The purpose of this test is to ensure the trigger sprayers can empty chemical without defect, specially for those paired with high volume reservoirs. Supplier usually have customized machine to operate this test.