Abstract: An air driven double diaphragm pump including two opposed pump chambers with an air motor having air chambers therebetween. The pump chambers and air chambers form pumping cavities divided by diaphragms. Each pump chamber includes an inlet ball valve and outlet ball valve. An inlet manifold is positioned below the pump chambers and an outlet manifold above. Tie-rods extend both across the pump from one pump chamber to the other with nuts to place the assembly in compression. Tie-rods also extend from the outlet manifold through the pump chambers, to the inlet manifold and to feet mounted therebelow. Two plates, one to either side of the air motor extend to grooves in the inlet and outlet manifold and also extend to grooves in the pump chambers so as to close of the side of the pump structure. With the plates, an outlet manifold is provided from which air may be exhausted remotely. The ball valves include small diametrical clearance and a limitation on lift for added performance.

Abstract: An air driven double diaphragm pump including two opposed pump chambers with an air motor having air chambers therebetween. The pump chambers and air chambers form pumping cavities divided by diaphragms. Each pump chamber includes an inlet ball valve and outlet ball valve. An inlet manifold is positioned below the pump chambers and an outlet manifold above. Tie-rods extend both across the pump from one pump chamber to the other with nuts to place the assembly in compression. Tie-rods also extend from the outlet manifold through the pump chambers, to the inlet manifold and to feet mounted therebelow. Two plates, one to either side of the air motor extend to grooves in the inlet and outlet manifold and also extend to grooves in the pump chambers so as to close of the side of the pump structure. With the plates, an outlet manifold is provided from which air may be exhausted remotely. The ball valves include small diametrical clearance and a limitation on lift for added performance.

Abstract: A vibrating element transducer is provided in which a vibrating element and a substantially non-vibrating reference element are positioned side by side and illuminated via an optical fibre. The surfaces of the vibrating element and the reference element are formed at slightly different distances from the end of the optical fibre. The differing distances are arranged such that interference between the light reflected from the vibrating element and from the reference reflector can be used to determine the frequency of vibration of the vibrating element.