Abstract: A control system is disclosed for turning a diesel engine on and off to power a refrigeration plant, based on temperature requirements. The desired temperature limits are preset, and when these limits are exceeded, a first timer is set for a desired delay, during which the engine is off; delay times of up to one hour are usual. At the end of this delay time, the first timer will activate glow plugs in the engine. Simultaneously with turning on the glow plugs, a second timer actuates the engine starter after a short delay to start the engine. During the delay period set by the first timer, the diesel engine will be off, and hence, the control system saves diesel fuel and reduces engine maintenance. An electronic circuit for operating the timing system is also disclosed.

Abstract: An electrical circuit adapted to control the operation of a refrigerant compressor in an automotive type air conditioning system. The electrical circuit has a pair of branch circuits, an impedance for connection in the branch circuits so as to be respectively energized and shunted therein, and condition responsive devices for enabling and disenabling one of the branch circuits. Switching means is operable for sequentially energizing and then shunting the impedance in the branch circuits to control the energization thereof subject to the enablement and disenablement of the one circuit branch by the condition responsive device.A method of operating an electrical circuit to control the operation of a refrigerant compressor in an automotive type air conditioning system is also disclosed.

Abstract: A vapor compression cycle device with variable thermal capacity is provided with a means and a method for controlling device capacity modulation and evaporator superheat. Multi-component working fluid liquid flow from each of a pair of accumulators in a closed circuit device is regulated either in response to sensed thermal demand or in response to sensed working fluid vapor superheat.

Abstract: An energy efficient refrigeration system having a valve in series with a fixed flow restrictor between the condenser and evaporator of the system. The valve is controlled to permit fluid flow whenever the compressor is running, and when the compressor is not running, only in the event the pressure at the outlet of the compressor is above a preselected pressure. The preselected pressure is a high pressure, such as would prevent starting of the compressor, which, in the illustrated embodiment, is a rotary compressor. The pressure sensing structure, in the illustrated embodiment, utilizes an analog of the pressure of the liquid refrigerant within the condenser and, more specifically, utilizes a temperature condition which corresponds to the liquid pressure therein. Alternatively, the temperature sensing may be of the condenser or of the ambient space in which the condenser is housed.

Abstract: A cryogenic food product freezing tunnel including an elongated housing having a food product entrance at one end, a food product exit at the other end, a food product conveyor extending through the tunnel, a cryogen input near the food product exit, an exhaust stack near the food product entrance with an exhaust blower atop the stack, a plurality of cryogen circulating fans spaced along the length of the tunnel, a variable speed directional blower intermediate the cryogen input and the food product entrance, a cryogen input control, and a temperature sensor positioned between the directional blower and the cryogen input.

Abstract: A conveyor system with cooling means is provided and comprises an elongated frame defining a conveyor track. An elongated conveyor is mounted within the frame so that a portion of the conveyor extends longitudinally along the conveyor track while a suitable motor longitudinally drives the conveyor along the conveyor track in a first direction. A plurality of cooling stations are also secured at longitudinally spaced positions along the frame so that the cooling stations are longitudinally adjacent each other. Each cooling station further includes a fluid reservoir beneath the conveyor track and a spray head positioned to spray fluid down onto the conveyor track. A pump is also provided for each cooling station and has its inlet connected to the fluid reservoir for that station while its outlet is connected to the spray head at the cooling station.

Abstract: A device to increase the efficiency of a conventional, air-to-air heat pump in the heating mode when the outside temperature falls below a selected value comprising a solar evaporator coil in refrigerant flow communication with the refrigerant connecting lines of the heat pump between the indoor condenser and the compressor to supply the additional heating capacity. Means are provided for selectively directing refrigerant through the solar evaporator coil when the temperature of the air surrounding the solar evaporator coil rises to a predetermined level and the temperature or pressure of the refrigerant within the heat pump connecting lines falls to a preselected point.

Abstract: The invention relates to a method and an installation for the refrigeration by discontinuous charges of objects in bulk which occupy a long thermally-insulated zone, the method comprising essentially the steps of: carrying out the complete refrigeration of the objects located in a longitudinally-restricted portion of the thermally-insulated zone by circulating a main flow of cooling gas longitudinally inside the restricted portion, partly re-cycling the cooling gas outside the thermally-insulated zone to an injection station for frigorific energy such as refrigerated gas in the liquid or solid state, precooling the objects located in a remaining portion of the insulated zone by the longitudinal circulation of an excess flow of non-re-cycled cooling gas through the remaining portion followed by evacuation to the atmosphere, circulating all the main flow of cooling gas longitudinally through the remaining portion of the insulated zone, and re-cycling an excess flow of said cooling gas outside said zone to the f

Abstract: A method and apparatus for controlling the operation of a refrigeration system, for example, is provided. Refrigeration systems commonly include a compressor, an evaporator coil, a condensing coil and an expansion valve inserted in the refrigeration line between the evaporator coil and the condensing coil. In the preferred form of the invention, an electrically controlled expansion valve is operatively connected to control means. The control means includes a pair of sensors. The control means is used to control expansion valve operation so that evaporator operation is maximized, regardless of load on the system. Control is accomplished, in one embodiment, by sensing the temperature along two points of the evaporating coil, and using the control means to maintain a predetermined temperature relationship between the two points.

Abstract: A system for defrosting a heat pump system employing a temperature difference type defrosting apparatus, wherein a heat sensitive means is provided at one portion of a pipe connecting an indoor heat exchanger with a four-way valve, and means provided between the pipe and the heat sensitive means for controlling the time required for transmitting the temperature of the pipe to the heat sensitive means. Owing to this system, the defrostation can be completely conducted and the defrosting cycle can terminate as soon as the defrosting has completed.

Abstract: Freezing apparatus in which food is quickly frozen comprising five coils, two joined in series to form a first set and two joined in series to form a second set, the exhaust of the two sets being delivered to the fifth coil in a pre-cooling chamber where food is introduced by a conveyor to the freeze tunnel. Each of the five coils is positioned in a separate chamber in the tunnel and thermal couple sensors deliver signals which are compared to a set-point signal in proportional controllers to control the flow of liquid nitrogen to each set of coils. Flow from the first and second sets of coils is vented to atmosphere and heater apparatus adjacent the fifth coil is energized when the temperature of nitrogen vapor discharged from the fifth coil is less than a predetermined value which results when formation of ice on the surface of the fifth coil reduces exchange of the heat between air circulated over the fifth coil and nitrogen vapor flowing therethrough.