Abstract: A refrigeration system including an evaporator defining an evaporator envelope and positionable to condition an airflow, the evaporator including an airflow inlet, an airflow outlet, and one or more refrigerant coils. The refrigeration system also includes a pressure sensor that is positioned to detect an outlet air pressure at or adjacent the outlet, and positioned to detect one or both of an ambient air pressure and an inlet air pressure and to generate a signal indicative of the corresponding air pressure. A control system in operative communication with the pressure sensor to determine a pressure differential based on the signal indicative of the outlet air pressure and the signal indicative of the ambient air pressure or the inlet air pressure, the control system configured to selectively initiate a demand defrost of the evaporator based on the determined pressure differential.

Abstract: In a graphite material comprising a mass of expanded graphite particles compressed together so as to form a graphite foil, the graphite foil is provided with a plurality of apertures disposed on at least one surface thereof so as to substantially prevent formation of bubble-like deformations which occur when the graphite foil is heated and/or placed in a vacuum. The method of making the invented foil and devices used to make said foil are also disclosed.

Abstract: A multiposition valve having a dynamic slide plate with at least one cavity is provided with a stationary plate intermediate such dynamic plate. The stationary plate has a plurality of through-bores for providing fluid connection to fluid passageways in the valve housing. The stationary plate can be inverted to selectively provide a variety of valve functions for any given dynamic valve plate position.

Abstract: A pressure-regulating valve having a force-feedback arrangement for indicating the fluid delivery, has a force cam rotatable along with an actuator member, shaft arrangement which controls the fluid delivery. At least one cam slot is formed in the force cam at an angle to the axis of the force cam. An annular ring is fixed within the valve housing in a coaxially surrounding relation to the force cam. At least one guide slot is formed on the annular ring parallel to the axis of the annular ring and adjacent the cam slot formed on the force cam. A follower pin extends between the adjacent cam and guide slots and is axially movable under the influence of a cam force exerted upon rotation of the force cam. A feedback piston is movable within a piston chamber located adjacent the force cam. The feedback piston contacts the follower pin which is a function of the delivered fluid value. The piston force is exerted in a direction opposite movement of the follower pin resulting from rotation of the force cam.

Abstract: A brake control arrangement for use with a multiple disk brake system having a plurality of disk brake actuators which exert a braking force in relation to the fluid pressure presented to a service braking portion contained therein. A handle valve is operable over a range of travel for delivering a braking fluid pressure to be directed to a first input of one of a purality of shuttle valves. This braking fluid pressure, however, is first directed through one of a plurality of flow paths selected by a selector valve arrangement. The selector valve arrangement can be sequenced to direct the initial braking fluid pressure through a different one of the plurality of flow paths upon receiving a sequencing count signal transmitted from a counter valve arrangement. A pilot operated relay valve has a pilot portion which receives the braking fluid pressure and opens the relay valve when the braking fluid pressure reaches a predetermined value.

Abstract: An inhibit lock arrangement for a marine engine controller including a valve-operating shaft axially movable by an operator's handle, when set in a "start" position, for opening a valve whereby a fluid pressure signal is transmitted to the engine to start the engine. Axial movement of the shaft may be blocked by a piston rod actuated by a cylinder when the cylinder is pressurized by a pressure signal indicating an undesirable engine operating or malfunctioning condition. A pair of pivotable latches disposed on each side of the operator's handle for retaining the handle in a neutral position until a release piston is actuated by the operator for releasing the latches and permitting the handle to be moved through a slot but not into the "start" positions until the undesirable condition has been eliminated.

Abstract: A control system for regulating exhaust gas pressure in a furnace smokestack by means of three power cylinder actuated butterfly valves in the smokestack opening. An electronic control circuit provides digital output signals, which operate spool valve devices via which a hydraulic fluid circuit is established to control the power cylinders. In a trim mode control circuit, a first comparator senses a difference between the actual stack pressure and a desired pressure. The comparator output is converted by an analog to digital section to provide the digital output signals for control of a single butterfly valve. A rangefinder mode control circuit includes a second comparator that senses an output from the first comparator in excess of a predetermined value.

Abstract: An electronic balance control circuit includes an OP-AMP comparator circuit for receiving a command signal and a feedback signal. A positive OP-AMP detector circuit for causing a first buffer trigger circuit to fire a first triac to energize a first output when the command signal is less than the feedback signal, and a negative OP-AMP detector for causing a second buffer trigger circuit to fire a second triac to energize a second output when the command signal is greater than the feedback signal.

Abstract: An operting handle assembly for actuating a valve or the like including an adjustable actuating cam member that controls the degree of deflection of the valve to obtain different output pressures for a given handle position, for example, and an adjustable friction brake mechanism that sets the desired tension for handle operation.

Abstract: An electronic control module comprising an operational amplifier used as a comparator senses the difference between the throttle settings of a master and slave engine as detected by a potentiometer associated with each engine's throttle control apparatus in order to accordingly adjust the control signal of a fluid pressure actuator of the slave engine, which actuator in turn adjusts the slave engine throttle setting until it corresponds to that of the master engine, at which point the slave engine throttle actuator control signal is maintained constant by reason of the operational amplifier sensing such correspondence.