| 摘要 |
A backpack spray apparatus for applying insecticides and fertilizers comprises a large tank in which is mounted a pressure vessel. A pumping assembly is connected with the bottom portion of the pressure vessel and also with the bottom portion of the container tank. It consists of a double-acting piston assembly, a valve, and passages to connect a portion of the cylinder chamber above the piston assembly to the pressure vessel and to the container tank, so that upon reciprocation of the piston there is pumping of liquid from the container tank to the pressure vessel. There is also a connection between the portion of the cylinder chamber below the piston assembly and the lower portion of the container tank, so that upon reciprocation of the piston assembly there is pumping of the liquid back and forth. An operator-actuated handle reciprocates the piston assembly. There is no diaphragm associated with the pumping assembly-all pumping being done by the pumping assembly. Any liquid that leaks from the piston assembly does not drop onto the operator or the earth but instead joins liquid being pumped back and forth as above indicated.
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