Abstract: A vapor compression system in which a quantity of a refrigerant circulates between at least two pressure levels in a condenser and an evaporator respectively, comprises a compressor (1) for increasing the pressure of refrigerant vapor; a condenser (5) for high pressure refrigerant vapor received from the compressor; an expansion device (13) such as a valve across which the pressure differential between the condenser and the evaporator is maintained, to control the withdrawal of liquid refrigerant from the condenser according to the volume of liquid refrigerant that is within or behind it; an evaporator (15) for liquid refrigerant received from the condenser; a receiver (21) into which refrigerant is discharged from the evaporator, with a vapor withdrawal conduit (25) through which vapor is withdrawn from the receiver for supply to the compressor, the receiver including a reservoir (23) into which liquid refrigerant discharged from the evaporator collects, to control supply of liquid refrigerant to the compres

Abstract: Plate eat exchangers are disclosed which accommodate variations in the relative proportions of liquid and vapour refrigerant, allowing the refrigerant in the two phases to remain in equilibrium throughout the flow path through the heat exchanger. The flow path can be arranged to be boustrophedonic so that it comprises first and second sets of alternating parallel sub-channels in which the resistance to flow of refrigerant fluid along each of the sub-channels of the first set is greater than the resistance to flow along the respective adjacent sub-channels of the second set. The configuration of the channel for the refrigerant through the heat exchanger can be arranged so that the resistance to the flow of refrigerant is greater towards one end than towards the other end.

Abstract: Plate eat exchangers are disclosed which accommodate variations in the relative proportions of liquid and vapour refrigerant, allowing the refrigerant in the two phases to remain in equilibrium throughout the flow path through the heat exchanger. The flow path can be arranged to be boustrophedonic so that it comprises first and second sets of alternating parallel sub-channels in which the resistance to flow of refrigerant fluid along each of the sub-channels of the first set is greater than the resistance to flow along the respective adjacent sub-channels of the second set. The configuration of the channel for the refrigerant through the heat exchanger can be arranged so that the resistance to the flow of refrigerant is greater towards one end than towards the other end.

Abstract: A process and plant is provided for the production of nitric acid from atmospheric air in which the feed air is passed in succession through a number of stages each comprising a high temperature regenerative nitrogen fixation reactor followed by a catalytic oxidation reactor and a nitric oxide absorber, all operating at superatmospheric pressure. Heat is exchanged between the inlet and outlet gas streams of each stage absorber. The compressors are driven by a turbo-expander powered by the exit gas stream in which fuel has been burned upstream of the turbo-expander. The nitrogen fixation reactors each consist of a pressure vessel enclosing a gas-permeable refractory wall surrounding a furnace chamber in which fuel is burned, the interior of the vessel being divided into two sections by an impermeable wall with a gap for flow through in the furnace zone.

Abstract: In a fractional distillation process and apparatus two columns are intercoupled to provide variable reboil in one and variable reflux in the other so as to approach closely to thermodynamically ideal fractionation. The variable reboil column has a series of heat transfer assemblies at different levels up its height and these are fed with vapor withdrawn from respective different levels of the variable reflux column. Partial condensation of each withdrawn stream takes place in the respective heat transfer assembly, after which the partially condensed stream is returned to the variable reflux column at a level close to the level at which the corresponding vapor was withdrawn. The variable reflux column will ordinarily be at a higher pressure, and mounted at a lower level than the variable reboil column.

Abstract: In a gas compression system employing a positive-displacement rotary compressor, liquid is injected into the compressor which is the liquid phase of the gas or vapour being compressed and the compressor temperatures are maintained at about the saturation temperatures of the gas or vapour. The quantity of liquid injected is sufficient to fill, at least partially, the internal compressor clearance gaps. An electric driving motor is contained with the compressor in another chamber of the same of casing and the motor windings are cooled by being bathed in the wet gas mixture leaving the compressor discharge.

Abstract: A screw compressor, compressing refrigerant gas in a refrigeration system, which has liquid refrigerant passed back through it, in counter flow to the gas being compressed, for sealing the rotor clearances. The liquefied gas from the condenser of the system returns to the evaporator either wholly by way of the compressor or partly by way of the compressor as aforesaid and partly through a bypass equipped with an expansion valve.