Abstract: An aspiration-type chemical sprayer for dispensing small quantities of a liquid based chemical into a stream of carrier fluid is disclosed. The sprayer includes a sprayer head assembly sealingly mounted onto a container holding chemicals such as pesticides or fertilizers. A carrier fluid control valve in the sprayer head assembly controls carrier fluid flow from a pressurized source of water past an aspiration orifice which forms the terminal end of an aspiration passageway in communication with the chemical within the container. A rod valve connects the aspiration orifice to the aspiration passageway and the container interior to atmospheric pressure when slid into an open position while providing simultaneous closure of the aspiration and vent passageways so as to seal the chemical in the container when slid into a closed position. The rod valve includes a pair of spaced annular integral sealing ridges and is molded in one piece of a plastic material.

Abstract: An aspiration type chemical sprayer for dispensing small quantities of a liquid based chemical into a stream of carrier fluid is disclosed. The sprayer includes a sprayer head assembly sealingly mounted onto a container holding chemicals such as pesticides or fertilizers. A unitary valve in the sprayer head assembly controls carrier fluid flow from a pressurized source of water while simultaneously providing a controlled aspiration rate and full communication of the container interior to atmospheric pressure. The valve additionally includes simultaneously closure of the carrier fluid, aspiration and vent passageways so as to seal the chemical in the container when the sprayer is not being used.