Abstract: A piston flow meter for measuring the flow of a gaseous fluid, such as ambient air, through the flow meter by timing the displacement of a piston in a hollow precision bore flowtube over a fixed distance. The piston is reciprocated from opposite ends of the flowtube by a poppet valve which controls the direction of movement of the piston in the flowtube. Ambient air is drawn into the flow tube from the atmosphere by an external pump connected to an inlet at one end of the flowtube. The flow meter includes a damping assembly for damping pulsations in gas flow through said flowtube with the damping assembly preferably located adjacent the pump inlet to the external pump. The damping assembly comprises damping means which includes a porous member and at least one elastic diaphragm contiguous thereto with the porous member having a multiplicity of voids and a plurality of open channels extending through the porous member to the elastic diaphragm.

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: A positive displacement piston flow meter for measuring air flow comprising a hollow flowtube, preferably arranged in a vertical orientation, having a movable piston disposed in the flowtube for movement between a starting position, preferably at the bottom end of the piston stroke, and an elevated position at the top end of the piston stroke. The piston is reciprocated by means of a pressure relief control valve assembly which controls the ascent and descent of the piston. The piston is physically connected to the pressure relief control valve assembly by means of a flexible string, which causes the piston to automatically close the valve assembly for automatic operation on reaching the bottom end of the piston stroke and to reverse direction.

Abstract: A fluid flow measuring device having a positive displacement piston in a precise bore glass flowtube, with flexible diaphragms at opposite ends of the flowtube, to seal the flowtube from the ambient environment. The flowtube is filled with a pure fluid or gas for uncontaminated operation of the piston. Movement of the piston within the sealed flowtube is controlled by controlling the movement of each diaphragm. The diaphragms are supported in a housing connected to each opposite end of the flowtube, with a plenum chamber in communication with each diaphragm, and with means for the ingress and egress of the fluid under flow measurement with the plenum chamber.

Abstract: A reciprocating 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 one position at or near the bottom end of the flowtube, and an elevated position at or near the upper end of the flowtube. The valve assembly is mechanically activated at each opposite end of the piston stroke to permit the piston to reciprocate between each opposite end in response to the presence of a gas flow.

Abstract: An air sampling and alarm control system for detecting the presence of a toxic contaminant in the atmosphere and for providing an audible alarm when insufficient gas flow is present in the system to adequately test for the presence of the contaminant. The alarm control is provided by a pressure switch which is electrically connected in circuit with an audible alarm and pneumatically connected in circuit with the gas flow line connecting the sampling pump to the sampling detector.

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 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.

Abstract: A soap film gas flowmeter comprising a hollow flow tube having opposite open ends through which a soap bubble is propelled with one open end extending into a first closed chamber housing the soap solution and the opposite open end extending into a second chamber. Inlet gas is fed into the first chamber, passed through the flowtube and discharged from the second chamber. A manually movable piston like member is provided for generating a soap bubble at the bottom open end of the flowtube. The flowtube has an opening in it for providing an open passageway for inlet gas to pass through the flowtube when the bottom open end of the flowtube is covered by the soap solution.

Abstract: The dual mode gas sampler and pneumatic flow control system of the present invention includes a flow control valve having a manually adjustable flow restricting orifice, a two position mode select valve, a flow controller and a vacuum pump for drawing gas from the atmosphere through a load representing either a single test article with flow being held constant or multiple test articles with pressure held constant. In one position of the mode select switch the flow controller maintains mass flow through the load constant by regulating a supplemental flow of gas from the discharge side of the pump to the suction side of the pump in response to the pressure differential across the flow restricting orifice. In the other position of the dual mode switch the flow controller regulates the supplementary flow of gas from the discharge side to the suction side of the pump in response to the pressure differential across the pump with the flow control valve bypassed.

Abstract: The fluid Sampler is used to sample gases in a collecting device and includes a flow control valve having a manually adjustable flow restricting orifice and a vacuum pump for drawing gas from the atmosphere through the collecting device and flow control valve to form therethrough a primary flow path. A flow controller is used to supply a supplemental flow of gas taken from the discharge end of the vacuum pump and supplied to the suction end of the vacuum pump in response to the differential in pressure across the flow control valve. The supplementary flow rate is automatically adjusted to maintain the differential in pressure constant.

Abstract: An air sampler constructed as an integrated unit which can be attached to the clothing of personnel operating in an area where the air must be sampled. The sampler includes a pump, a damper, a regulator, a filter for removing dust or dirt from the air being sampled, and collecting or processing means for the sampled air. The pump is driven by a motor provided with a control which maintains the flow of air through the sampler constant. The regulator is connected directly between the inlet and the outlet of the sampler. It includes a pair of chambers separated by a flexible diaphragm, one chamber connected to the outlet and the other to the inlet. For a pressure differential exceeding a predetermined magnitude between the outlet chamber and the inlet chamber, the diaphragm by its flexing opens a valve to permit air to flow from the outlet to the inlet. The filter is in a transparent container so that it can be seen and removed when it becomes excessively loaded with dirt.

Abstract: A portable holder assembly in combination with one or more gas detection tubes each of which contain chemical sorbent material. Each sorbent tube has a tapered neck at each opposite end with an opening adapted for drawing ambient gas through the sorbent material. The holder assembly comprises an open ended hollow tubular shell surrounding each gas detection tube, end fitting means for closing the open ends of each shell to form a closed chamber between each shell and each gas detection tube and an O-ring mounted in each end fitting means in surrounding engagement with the tapered neck of each tube for suspending each tube within each shell and for sealing off the open ends of each tube from the closed chamber.