Abstract: A flow measuring apparatus of an embodiment is provided than comprises a cylinder and a piston movable in the cylinder between first and second positions. The piston divides the cylinder's interior area into first and second portions. A biasing member urges the piston toward the first position. A first fluid passageway allows fluid to bypass the piston, and a second fluid passageway is in fluid communication with the first fluid passageway and with the first portion of the cylinder. The second fluid passageway provides fluid to the first portion of the cylinder to move the piston toward the second position. A flow diverter is movable between a first flow position that allows fluid to pass through the first fluid passageway to the outlet and a second flow position that causes fluid to flow into the second flow passageway and into the first portion of the chamber.

Abstract: In one embodiment, a constant-flow valve assembly is provided that comprises a first fluid passageway carrying fluid at a first fluid pressure, a piston chamber, and a second fluid passageway connected to the chamber and carrying fluid at the second fluid pressure. A third fluid passageway is configured to carry fluid at a third fluid pressure. An adjustable valve member is provided between the chamber and the third passageway to provide constant fluid flow to the third passageway. An adjustable restrictor assembly is positioned between the first and second fluid passageways. An inlet portion of the restrictor assembly receives fluid at the first fluid pressure and directs the fluid to a restrictor. An outlet portion receives fluid from the restrictor and directs the fluid to the second fluid passageway at the second fluid pressure.

Abstract: A vehicle fleet management information system identifies location and direction of movement of each vehicle in a fleet in real-time, and automatically reports such information, as well as status of predetermined events in which the vehicle is engaged, directly to the fleet manager. Each fleet vehicle has an assigned time slot to transmit its reporting information over a communications network without interfering with transmissions from other vehicles in their own respective time slots. A timing control phase lock loop (PLL) provides precise time synchronization for timing corrections from a global positioning system (GPS) based time reference. A dual band full-duplex interface of the network has TDMA on one-half and broadcast on the other half. Microprocessor time processing units in components of the network perform precise clock synchronization. Space diversity performed on received vehicle transmitted messages avoids data corruption.

Abstract: In one embodiment, a flow control valve includes a valve body having an inlet, an outlet, a flow passageway coupling the inlet to the outlet, and a cavity with first and second chambers. The valve further includes a hollow piston disposed in the first chamber and a seal separating the first and second chambers. The seal has a section within the piston that is exposed to the fluid in the first chamber. The section of the seal defines a first effective area. The valve also includes a biasing member configured to urge the piston, and a reference pressure passageway in fluid communication with the inlet and the second chamber. The valve can further include a piston seat that has a second inner effective area at least approximately equal to the first inner effective area.

Abstract: An apparatus to control fluid flow to an approximate fixed rate is disclosed. The apparatus includes a housing (12), an orifice (22), a diaphragm (24), and a cage (26). The housing has two ends, an inlet end (18) having an inlet opening and an outlet end (20) having an outlet opening. The ends are arranged and configured to receive piping (14 and 16). The orifice is disposed within the housing. The orifice has an upstream end and a downstream end with a seat (34) formed in the upstream end. The fluid flows over the seat and through the orifice before exiting the outlet end of the housing in normal flow. The diaphragm is disposed within the housing adjacent and upstream of the seat of the orifice. The diaphragm has an upstream side, a downstream side, and sidewalls. The downstream side of the diaphragm is opposite the seat such that a pressure drop across the diaphragm pulls the downstream side of the diaphragm toward the seat. The cage surrounds at least a portion of the sidewalls of the diaphragm.