Vintage Garden Syringe Sprayers    

Back Continuous Action Sprayers -   Air Compression Type

Main components are main barrel (1 yellow), pump barrel (red), outlet pipe (2 blue) and valve assembly (green - valves A and B). The supply pipe is attached  to  the valve assembly. The inner end of of outlet pipe has a fixed curved baffle plate which almost completely fills the main barrel. On the other end of this pipe  is  the nozzle. The pump barrel houses the plunger rod and piston.     

1. At the start with the supply pipe in the liquid, there is air in  the pump barrel, main barrel and supply pipe.

2. Pulling the plunger rod causes air to be sucked in via the supply pipe. Valve B is open and valve A is closed

3. On the push stroke valve A is open and valve B is closed causing the air to be forced into the main barrel where it escapes slowly via the outlet pipe and nozzle.

4. Repeated pumping first pressurises the air in the main barrel, then sucks in  liquid which is in turn forced into the main barrel.

5. When there is sufficient liquid in the main barrel, the pressure within the barrel caused by the compressed air forces the liquid out through the outlet pipe.

6. Continued pumping maintains the supply of liquid and also the pressure within the main barrel. This gives a continuous spray.

When the pump is horizontal or upwards the air remains trapped at the forward end. If the sprayer is pointed downwards the rush of water  is checked  by the baffle and air is able to escape to the opposite end of the the main barrel around the pump barrel.  The other advantage of this design is that both valves are easily reached  for cleaning.

The design was patented by W T French &  Son in March 1927 (patent GB267417) .

View inside the main barrel, showing the inner pump barrel, into which the plunger rod and piston fit.

Left - the valve assembly.  Right - upper part containing  valve A is fixed to the main barrel . Valve A controls the flow into the main barrel . The other open aperture (top) is into the pump  barrel. This is a slightly different arrangement to that illustrated in the patent.  The lower picture shows the nozzle pipe removed from the main barrel. Note the baffle and the right angle connection into the pipe.

Lower part of the valve assembly, containing valve B which control the flow from the supply pipe. The supply pipe attaches to this part of the assembly.    

Images are from a Mysto ’Gem’ No. 39 continuous sprayer.