Abstract: A piston flow meter for measuring gas flow through the flow meter comprising a hollow precision bore flowtube in a vertical orientation, with a movable piston containing a valve assembly for movement in concert with the piston between opposite ends of the flowtube. The valve assembly contains a latching mechanism, preferably a magnetic latch, to provide a positive seal across the piston. The magnetic latch is opened when the piston strikes a spring-loaded stop at the top end of the piston stroke, and is closed at the bottom end of the piston stroke.

Abstract: An electrically driven double-acting diaphragm air pump having a diaphragm-driven system including an eccentric for the motor shaft, a freely movable yoke having a solid framework solely supported by the diaphragm system with one end connected to a first diaphragm assembly, and at an opposite end to a second diaphragm assembly, and with the yoke having a large central opening. The eccentric is coupled directly to the solid framework through a yoke driver. The yoke driver is rotatably connected to the solid framework at one end of the framework adjacent to the first diaphragm assembly, and is coupled to the eccentric through ball bearings, with the opposite end of the yoke driver suspended for free movement within the large central opening of the solid yoke framework.

Abstract: The fluid sampler of the present invention comprises a single-acting pump assembly having a housing, an inlet port and an outlet port, a valve unit including a single inlet valve and a single outlet valve, a control diaphragm mounted in the housing to form a pumping chamber in communication with said inlet valve and said outlet valve, a reciprocative piston for reciprocating said control diaphragm, a motor for driving said piston with said piston being located in a substantially enclosed cavity separated from said pumping chamber by said control diaphragm and a damping assembly integrated in said pump housing for providing a highly damped fluid flow through said pump.

Abstract: A soap film gas flow measuring device for computing the rate of gas flow through the device by detecting each moment in time when a soap film crosses two positions in a flow tube through which the soap film is propelled by the gas flow, computing the time difference and calculating the flow rate. A set of insulated wire conductors is inserted through the flow tube at each position at which the soap film is to be detected and circuit means is used to detect a predetermined drop in conductivity between each set of conductors corresponding to the crossover point.

Abstract: A gas flow measuring device comprising a flowtube, a soap bubble generator for generating a film of soap, a manually adjustable member for controlling the transfer of the soap film to the flowtube and a set of detectors spaced apart along the flowtube for measuring the time displacement of the soap bubble between the spaced positions of the detectors. The manually adjustable member is preferably a hoop surrounding the flowtube. A soap bubble is formed by immersing the hoop into the soap solution and withdrawing it. A soap film is transferred to the flowtube by raising the hoop to the mouth of the flowtube. In a second embodiment, a sleeve with slots surrounds a flowtube with slots. The sleeve is rotated into alignment with the flowtube to transfer a soap film.