Abstract: Apparatus for monitoring an engine of a vehicle having an ignition switch operable between on and off positions, a vehicle power supply, and an electrical load, including the engine, selectively connectable to the vehicle power supply via the ignition switch. A controllable switching device is disposed between the vehicle power supply and the ignition switch. A timer accumulates time when the ignition switch is in the on position and the vehicle is stationary. If the timer reaches a predetermined time value the controllable switching device is actuated to disconnect the vehicle power supply from the ignition switch, to turn off the engine, if running, as well as disconnecting the electrical load energized via the ignition switch, limiting engine idle time, reducing engine wear and emissions, and terminating any drain on the vehicle power supply in the event the engine is not running.

Abstract: A eutectic beam, and method of constructing same, which includes a plastic housing, a eutectic solution, and a generally U-shaped evaporator tube having first and second spaced leg portions, ends of which extend outside the housing. The leg portions of the evaporator tube are supported by spaced plastic support elements which include cylindrical portions which snugly but slidably encircle the leg portions, and which further include support legs which extend outwardly from the cylindrical portion and are bonded to the housing. In a method step, the plastic support elements are positioned within a rotational mold at the time the plastic housing is formed, with the plastic support elements locating and supporting the evaporator tube within the mold cavity, and with the outer ends of the support legs becoming embedded in walls of the housing during rotational molding.

Abstract: The invention relates to methods of defrosting an evaporator coil of a transport refrigeration unit which includes microprocessor based electrical control. The electrical control maintains the temperature of a conditioned space at a predetermined set point temperature via hot gas heating and cooling cycles. The evaporator coil is defrosted to remove frost and ice by closing a damper to the served space and initiating a heating cycle. At the termination of defrost, a cooling cycle is initiated, but the damper is maintained in a closed position for a predetermined period of time to remove heat built up during the defrost process. The invention also detects damper malfunctions, including failure to close prior to defrost, and failure to open after defrost. The invention also evaluates manual and timed requests for a defrost operation, overriding the requests in response to predetermined conditions.

Abstract: A method of detecting conditions during the operation of a transport refrigeration unit which may cause shutdown, and then modifying the operation of the unit in an attempt to find an operating condition that will keep the unit operating safely. The unit includes a compressor driven by an engine operable at low and high speeds. Upon detecting an over-temperature condition of the engine a first modification is initiated, including switching the engine to low speed. If the engine temperature does not drop to a safe value, a second modification is initiated. If the engine was in low speed when the over-temperature condition was detected, the second modification is initiated immediately. Upon detecting a low oil pressure condition, the engine is switched to high speed. If the oil pressure rises to a safe level, engine operation is continued at high speed. Appropriate alarms accompany the modified operating conditions.

Abstract: A method of operating a transport refrigeration system having a refrigerant compressor driven by a prime mover. Electrical control maintains the temperature of a load in a conditioned space close to a desired set point via heating, cooling and null cycles, with the prime mover being started and stopped, as required, in response to the difference between the temperature of the conditioned space and a selected set point temperature, i.e., temperature error. Restarting of the prime mover is dynamically controlled by controlling the magnitude of the restart temperature error in response to the difference between the temperature of the conditioned space and ambient temperature.

Abstract: A transport refrigeration unit, and method of operating same, with the unit being associated with a vehicle having a drive engine and a cargo space to be conditioned to a predetermined set point temperature. The transport refrigeration unit includes a refrigerant compressor driven directly, or indirectly, by the vehicle engine. Sensors and control determine when the engine may be safely started and stopped under control of the transport refrigeration unit. A comparison between cargo temperature and set point temperature determines when a refrigeration cycle is required to maintain the set point temperature, and when the cargo space temperature is satisfied. The engine is started, when off, when the engine may be safely started and the cargo space requires a refrigeration cycle to maintain the set point temperature. The engine is stopped, when running, when the engine may be safely stopped and the cargo space is satisfied.

Abstract: A transport refrigeration unit, and methods and apparatus for monitoring the operation thereof, with the unit conditioning a load to a selected set point temperature via commanded cooling and heating cycles. A thermostat provides a digital signal as a function of the load temperature and the selected set point temperature, with each toggling of the least significant bit (LSB) thereof indicating a predetermined change in load temperature. A timer initiates a predetermined timing period with each toggling of the LSB, with the timing period being a dynamic function of the selected set point temperature. Expiration of the timing period before the next bit toggle initiates an alarm signal indicating the rate-of-change of load temperature is not within an acceptable limit for the selected set point temperature. A comparison of successive digital signals also results in an alarm signal when the direction of temperature change is not consistent with the commanded operating cycle.

Abstract: Methods and apparatus for eliminating the need for a float valve in a flash tank of a refrigeration system having an economizer cycle, improving stationary refrigeration systems and permitting a flash tank instead of a heat exchanger to be used in a transport refrigeration system having an economizer cycle. The refrigeration system includes a refrigerant compressor, a condenser, and an evaporator, with the flash tank being disposed between the condenser and evaporator. A liquid sub-cooling valve is disposed between the condenser and flash tank. The liquid sub-cooling valve opens and closes to maintain a desired degree of sub-cooling, with the liquid sub-cooling valve thus controlling refrigerant flow into the flash tank. Refrigerant flow out of the flash tank to the evaporator is controlled by a suction superheat thermostatic expansion valve. In a preferred embodiment, liquid leaving the flash tank is sub-cooled before entering the expansion valve.

Abstract: A compartmentalized transport refrigeration system which holds selected set point temperatures in at least first and second served spaces via heating and cooling cycles. The system includes a refrigerant circuit having high and low pressure sides, including a compressor, a condenser, a receiver, at least first and second evaporator sections respectively associated with the first and second served spaces, an accumulator, and a mode selector valve having heating and cooling positions. Control provides a heat signal when the need for a heating cycle in one of the served spaces is detected. The receiver is connected to the low pressure side of the refrigerant circuit for a predetermined period of time in response to the heat signal. At the end of the period of time the mode selector valve is operated from the cooling position to the heating position, and the connection between the receiver and low pressure side is terminated.

Abstract: Pre-trip operational methods and procedures for automatically checking predetermined functions and the operating performance of a transport refrigeration unit which includes a refrigerant compressor, and a prime mover for the refrigerant compressor which includes an internal combustion engine. The methods include the steps of measuring the current draw of predetermined electrical components with the prime mover stationary, starting the engine when the current draw is normal, determining if the speed of the engine is in an allowable range, commanding the unit to operate in a cooling mode, checking for adequate cooling capacity as a dynamic function of the temperatures of the return air, discharge air, and ambient air, commanding the unit to operate in a heating mode, determining if the unit is actually operating in the heating mode, and preparing an indication of a fault condition descriptive of any detected malfunction and/or marginal operating performance.

Abstract: A method of operating a transport refrigeration system having a compressor driven by a prime mover at a selected one of high and low speeds, an evaporator, and an evaporator blower driven by the prime mover. Refrigeration control provides an error value which controls the temperature of a load space to a predetermined set point via heating and cooling modes. The method includes the steps of driving the compressor at high speed during pull down, and injecting hot gas into the evaporator when the error is reduced to a predetermined value. The prime mover is maintained at high speed, to keep evaporator air flow at a high rate, continuing a relatively rapid temperature pull-down across the entire load space. The speed of the prime mover is reduced to low speed when the error is further reduced to a second value, which also initiates suction line modulation while maintaining hot gas injection.

Abstract: An eutectic beam which includes a plastic housing, an eutectic solution in the housing, and an evaporator tube in the eutectic solution having ends which extend outside the housing. The ends of the evaporator tube are adapted for connection to a refrigeration system. The evaporator tube is formed of copper having a thin protective coating on its outer surface formed of plastic, which is preferably a two component, filled epoxy resin system. The housing, in a preferred embodiment, is formed of a plastic, such as polyethylene, filled with a filler material selected to increase the thermal conductivity and thus the efficiency of the eutectic beam. In still another preferred embodiment, the filler material is also selected to increase both the electrical and thermal conductivity of the housing, with the housing including electrodes for electrically heating the housing to remove frost and ice build-up.

Abstract: A method of operating a compartmentalized transport refrigeration system having first, second and third compartments respectively served by a host refrigeration unit and first and second remote refrigeration units. The method includes the steps of providing a first signal when either of the first and second remote refrigeration units is in a cooling cycle, cycling the host refrigeration unit between cooling and heating cycles to hold a selected set point temperature of a fresh load in the first compartment, in the absence of the first signal, and providing a predetermined null period between the heating and cooling cycles of the host unit when the first signal is present. In a preferred embodiment a prime mover for a refrigerant compressor is operable at a selected one of high and low speeds, with the method including the step of preventing high speed operation when any remote refrigeration unit is in a heating cycle.

Abstract: A method of operating a transport refrigeration system having a refrigerant compressor driven by an internal combustion engine. Microprocessor based electrical control maintains the temperature of a conditioned space at a desired set point via heating, cooling and null cycles, with the engine being started and stopped, as required. During the engine starting process, a suction line modulation valve, if used, is closed, engine pre-heat time is selected, including using engine temperature to access a look-up table, and current draw is checked during pre-heat. Excessive current terminates pre-heat. Control diagnostics checks the voltage level on both sides of a refrigerant high pressure switch, before initiating engine cranking. Prior to stopping the engine, a control option initiates a heating cycle for a short time when null is being entered from a cooling cycle, to warm the evaporator and prevent premature starting of the engine.

Abstract: A method of monitoring a transport refrigeration system which is effective regardless of the temperature of a served space relative to a selected set point temperature. Different "windows" of acceptable and marginal performance are provided in the form of different minimum magnitudes of .DELTA.T, i.e., the algebraic difference between the return and discharge air temperatures, as a function of ambient and return air temperatures. The transport refrigeration system is thus monitored at all times, during both cooling and hot gas heating modes, and also including during initial temperature pull down of the cargo space, enabling an early warning to be generated for a marginal performance, and an early shut down to be initiated for unacceptable performance. In a preferred embodiment, a maximum value of .DELTA.T is also provided, which, if exceeded by the actual .DELTA.T, indicates a restricted air flow in the cargo space.

Abstract: An office space dividing system comprising office furniture components in combination with a plurality of structural rectangular frames having openings which may be left open or closed in varying degrees with a wide variety of fill options, which may be readily changed, to create the desired degree of privacy. The system combines the advantages of a full height office partition system with lockable doors, and an open plan panel system. An enlarged cornice accommodates both wiring and ambient lighting, with a cornice to ceiling space being left open or closed with a clerestory, as desired, without compromising the ability to install lighting fixtures and wiring. The rectangular frames have mitered stiles which, when assembled with other frames, and/or mitered fill pieces, create columns defining vertical wire ways which communicate with cornice wiring, work surface height wiring, and/or base wiring, as desired.

Abstract: A method of determining if the refrigerant charge in a refrigeration system is within an acceptable range, including the step of developing a model evaporator temperature-versus-time signature for a system known to have a recommended refrigerant charge level. The model developing step includes the steps of isolating an evaporator from a space to be conditioned by the system, operating the system in a cooling mode to cool the evaporator, trapping refrigerant in the cooled evaporator to introduce an instability into the cooling cycle, and continuing the cooling mode for a time sufficient for a system having an acceptable charge level to recover from the trapping step. A test signature is then provided for a system to be checked, using steps similar to those used to develop the model signature, and the test signature is compared with the model signature to determine if the refrigerant charge is within an acceptable range.

Abstract: A space dividing system which comprises a rectangular panel having a metallic frame which includes stiles and rails arranged to form a window. The stiles and rails each have a channel which faces the window and first and second spaced internal pockets which straddle the channel. Projectile resistant material is disposed in the first and second pockets of each stile, and a rigid rectangular layer of projectile resistant material is centered in the frame window with its outer edges extending into the channels and overlapping the first and second pockets. In a preferred embodiment, layers of acoustical insulation are respectively disposed against opposite sides of the rigid layer of projectile resistant material; and, the panel is supported by an arrangement which includes both a hollow metallic post filled with projectile resistant material, and a connecting joint structure which both blocks and deflects projectiles entering the joint.

Abstract: A method of automatically checking components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system. The transport refrigeration system has a prime mover which drives a refrigerant compressor and an alternator. The control includes a battery and a current shunt which measures battery current. During the automatic checking procedure, the prime mover is off, to provide a zero alternator output. Upper and lower battery current draw limits are provided for each component to be checked. Each of the components to be checked is energized and de-energized, with the microprocessor individually and successively connecting each component to, and disconnecting it from, the battery. The microprocessor compares the battery current draw of each component, when energized, with the associated battery current draw limits. An alarm is provided when a battery current draw is outside the associated draw limits, with the alarm identifying the associated component.

Abstract: A method of operating a transport refrigeration system having a refrigerant compressor driven by an internal combustion engine. Microprocessor based electrical control maintains the temperature of a conditioned space at a desired set point via heating, cooling and null cycles, with the engine being started and stopped, as required. During the engine starting process, a suction line modulation valve, if used, is closed, engine pre-heat time is selected, including using engine temperature to access a look-up table, and current draw is checked during pre-heat. Excessive current terminates pre-heat. Control diagnostics checks the voltage level on both sides of a refrigerant high pressure switch, before initiating engine cranking. Prior to stopping the engine, a control option initiates a heating cycle for a short time when null is being entered from a cooling cycle, to warm the evaporator and prevent premature starting of the engine.