Abstract: An improved screw conveyer with removable flighting includes a rigid helicoid flighting (1) having a passage along its axis defined by the inner edges of the flighting for receiving a shaft (10). The shaft is removably received within the passageway of the flighting, and complementary coupling means associated respectively with the flighting and the shaft cause rotation of the flighting when the shaft is rotated in the first direction, and permit removal of the shaft from the flighting when the shaft is rotated in the opposite direction. In the preferred embodiment, the complementary couplings include a reverse bend (6) in the end of the flighting, and a stop member in the form of a gapped annular washer (12) secured to the shaft. The shaft may be rotated to thread itself into the flighting with the flighting passing through the gap until the reversed bend is encountered, at which point further rotation causes rotation of the flighting.

Abstract: A pressure control system for an air distribution system which includes a supply blower (10), a distribution duct network (20) and a plurality of air outlets (22a, 22b), includes a plurality of pressure sensors (25a, 25n) positioned at various points in the air ducts to measure pressure therein. Controls are provided for selecting the lowest of the sensed pressures (42) and the low pressure signal becomes one input to a variable dead band controller (44). Another input is an adjustment (45) for commanding the desired system pressure. The controller compares the pressure to a dead band threshold established about the set point and delivers appropriate signals to an actuator (31) which operates through a linkage (32) to control the inlet vortex vanes (33) and hence the air flow of the supply blower. A wide dead band is used to avoid hunting of the system, but when a response is required a narrow dead band is used to ensure that the system drives to the set point.

Abstract: A centrifugal gas compressor having a shrouded rotatable impeller 14 in an impeller chamber 40, and provided with capacity control vanes 30 and a diffuser passage 18 throttle plate 38, is provided with surge control means including a thermistor 50 which senses a temperature rise beyond a predetermined value in the impeller chamber and exterior of the gas flow path through the impeller, and through relay means such as 52, 58 electrically connected to the thermistor 50 operates to change the compressor operation to a nonsurging condition.

Abstract: An improved system for control of defrost in a refrigeration system of the type wherein one or more evaporators are defrosted by hot gas from the compressor while one or more evaporators remain in refrigeration operation. Prior to operating diverting valves to establish defrosting gas flow in an evaporator, a liquid line valve is closed and the system is pumped down to a predetermined amount of refrigerant charge in the defrost loop. In a preferred embodiment, this is accomplished by first opening the liquid line valve to flood the system, then closing it for a predetermined time interval to pump down to the predetermined amount of charge prior to operating the diverting valves.

Abstract: An air conditioning system including an air flow limiter and indicator comprising, in combination: a chamber (24) extending from an inlet (21) to an outlet (22) for flow therebetween of conditioned air at greater than ambient pressure; a damper (63) in the chamber actuable to variably restrict the flow; apparatus outside the chamber, including an inflatable member (66) having inlet (70) and venting (42) openings, for actuating the damper in accordance with the state of inflation of the member; condition-responsive apparatus, including a fluid amplifier (72) supplying fluid from the chamber to the inlet opening, for causing inflation and deflation of the inflatable member; apparatus including a vane (32) in the conduit for responding to the rate of flow of the fluid in the conduit; apparatus (41, 57) normally closing the venting opening; and apparatus (43, 45, 55) operable by the vane as the rate of flow exceeds a predetermined value for unclosing the venting opening, to enable deflation of the inflatable mean

Abstract: A pressure control system for an air distribution system which includes a supply blower (10), a distribution duct network (20) and a plurality of air outlets (22a, 22b), includes a plurality of pressure sensors (25a, 25n) positioned at various points in the air ducts to measure pressure therein. Controls are provided for selecting the lowest of the sensed pressures (42) and the low pressure signal becomes one input to a variable dead band controller (44). Another input is an adjustment (45) for commanding the desired system pressure. The controller compares the pressure to a dead band threshold established about the set point and delivers appropriate signals to an actuator (31) which operates through a linkage (32) to control the inlet vortex vanes (33) and hence the air flow of the supply blower. A wide dead band is used to avoid hunting of the system, but when a response is required a narrow dead band is used to ensure that the system drives to the set point.

Abstract: A key-operated actuator includes a frame, an elongated bolt having a driving connection to the device to be actuated, a tumbler mechanism which enables bolt rotation only when a key having proper configuration is inserted. A frangible portion on the key axially displaces a non-rotatable sleeve which carries an anvil that breaks off the endmost frangible portion of the key. The driving connection between the bolt and the device to be actuated is at all times maintained, and the bolt is restricted to angular movement of a predetermined magnitude, there also being anti-backup means to ensure full bolt movement in both directions. A control disc is secured to the bolt and provides a portion of the anti-backup means, provides a portion of angular movement limiting means, provides an abutment that prevents bolt rotation when the last frangible portion has been broken off, and provides control for a further actuator that operates a further device.

Abstract: The invention is directed to removable heat exchanger tube assemblies in heavy duty equipment radiators in which the tubes are each separately removable if they become defective in service. An inwardly facing annular ledge or abutment is molded into the inside diameter of each upper and lower sealing member to receive the respective ends of the tubes and prevent vertical movement of the tubes in service. A flange or shoulder is also provided on the lower portions of each tube and engages the inside of the lower sealing member to further restrain downward movement of the tubes in service. Each tube may be removed by pushing the tube upwardly to overcome the upper ledge abutment and thereby lift the tube free of the lower seal. Each tube may then be removed sidewise from the radiator. Variations of the removable sealing arrangement can be made and are described herein.

Abstract: Condensing head pressure in a refrigeration system having its condenser exposed to low outside ambient temperatures is controlled to provide the minimum head pressure required for a given mode of operation. A hierarchy of operating modes, each with its associated pressure is established, including normal refrigeration, evaporator defrost and heat reclaim. The control system prevents system head pressure from going below the minimum required for the operating mode in effect at a given time, with modes requiring higher pressure overriding lower pressure modes when required. In heat reclaim operation, high pressure gas from the compressor is diverted through a heat reclaim coil, and a subcooling sensor or other sensing means controls system head pressure to the minimum pressure that will maintain full condensing in the heat reclaim coil, which is the most economical mode of operation.

Abstract: A beverage dispenser includes a source of pressurized carbonated beverage which is connected to a dispensing valve by a line extending through a refrigerated bath. In the bath, the line includes a thin-wall high-density polyethylene tubing portion having a wall thickness in the range of 0.018 to 0.028, preferably 0.025 inch, and a density in the range of 0.945 to 0.965, preferably between 0.95 and 0.96.

Abstract: A control system for a refrigeration system having an air-cooled condenser exposed to normal year round ambient temperatures. Head pressure is controlled in response to sensed subcooling of the refrigerant in the liquid line near the entrance to the expansion device, so as to prevent the occurrence of flash gas at the expansion device, while still allowing minimum head pressures so as to improve energy efficiency. In alternate embodiments, additional controls are provided for assuring at least a predetermined minimum pressure differential across the thermostatic expansion valve. In one preferred embodiment a two-bulb sensing technique is used for subcooling and pressure differential sensing. Both series and parallel condenser-receiver connection systems are disclosed, as are a number of different subcooling sensing and control embodiments.

Abstract: A beverage cooling bath includes a refrigeration evaporator immersed in water for growing ice thereon, there being a beverage cooling coil disposed elsewhere in such water. In order to turn the refrigeration system off when a sufficient amount of ice has built up on the evaporator, there is provided a control for doing so which includes a motor-driven impeller that directs a flow of water into a tube which divides, the one portion having an outlet through which such water normally flows along a freezing surface on the evaporator, and the other portion being a branch that leads to a sensing control which is responsive to an increase of water level or water pressure therein as a consequence of ice forming to block the other portion leading to the outlet.

Abstract: Apparatus for defrosting a heat exchanger, comprises a plurality of spaced parallel heat exchanger fins having sets of circular, collared, axially aligned apertures. The collars of each set coacting to define an essentially continuous tube. Refrigerant tubes pass through the essentially continuous tubes defined by a majority of the sets of apertures and are sized for engagement by the collars of the apertures in intimate heat conductive relation. Axially replaceable electrical heating elements traverse the essentially continuous tubes defined by a minority of sets of apertures instead of refrigerant tubes and the heating elements are sized to fit loosely in the apertures so the heat is transmitted from the element to the collars both by radiation and by conduction and so that axial relative movement between the elements and the collars is enabled.

Abstract: In the present invention, four valves are connected in tandem to form a closed loop. A pair of inlet channels and a pair of outlet channels are connected between the valves and in such a manner as to form a bridge-circuit arrangement. The valves are preferably disc-shaped chambers with orifices in their rooves by means of which they interconnect with one another. In each valve is also located a diaphragm resting on the floor of the valve chamber and which may be raised and pressed against the roof of the chamber to cover the orifices there, thereby closing that particular valve. By thusly closing one pair of diagonally opposing valves or the other, the connections between the inlet and outlet channels can be reversed. The diaphragms can be raised by applying a relatively high pressure to their undersides through orifices located in the floors of their respective valve chambers.