Showing papers on "Gas compressor published in 1989"

Gas delivery means

Abstract: This invention is a respiratory gas delivery system to cyclically deliver a controlled volume of air to a patient. The system includes a variable speed rotary compressor (10) driven by a rotary electric motor (12) and a directional valve means (16), all of which are controlled by a microcomputer (26). The microcomputer includes means to select a reference value for the delivered air volume (44), means to measure the instantaneous flow rate (40), means to integrate the flow rate measurement during a delivery interval and means to adjust the compressor speed on the next succeeding delivery interval following a delivery interval in which the flow rate measurement is integrated.

Active stabilization of compressor surge

Abstract: This paper describes the stabilization of compressor surge by an active method. It is known that surge follows when small disturbances grow in an unstable compression system, and that small growth can be modelled through a linear stability analysis. An active element is here introduced to counter any tendency to instability and the control law governing the active stabilizer is determined from linear theory. We follow precisely the suggestion put forward by Epstein et al. (1986) and verify that their theory conforms to practice. The theory is verified in an experiment on a compression system whose plenum volume is controlled. Suppression of the flow instability was achieved by switching on the controller and the compressor was made to operate stably on a part of its characteristic beyond the nature stall line. Furthermore the controlled compressor is much more resilient to external disturbances than is the natural case. The controller is even effective on deep surge – a feature of great interest but hardly predictable from the Epstein et al. initiative for this kind of study.

Unsteady compressible two-phase flow model for predicting cyclic heat pump performance and a comparison with experimental data

Abstract: A dynamic model of vapour compression heat pumps is presented. Due to the importance of thermal expansion and compressibility effects, a detailed mathematical treatment of the condenser, evaporator and accumulator is given. Brief descriptions of the modelling techniques used for the remaining heat pump components and the solution methodology employed in the complete heat pump model are presented. Lumped-parameter models were developed for the expansion device, natural-gas-fueled internal combustion engine and compressor (open and hermetic). Inclusion of an appropriate void fraction model was found to be essential in determining the spatial refrigerant mass distribution, therefore a discussion pertaining to this model is also given. Simulations results and experimental data are favourably compared for transient operation of a hermetic water-to-water heat pump and an air-to-air system with an open compressor. The spatial variations of temperature, enthalpy, mass flow rate and density are predicted at each point in time for the two heat exchangers. The refrigerant pressures in the condenser and evaporator are determined such that the boundary conditions for the governing set of parabolic partial differential equations are satisfied. The summary provides a list of on-going work in the area of heat pump simulation and applications.

Hybrid vapor-compression/liquid desiccant air conditioner

Abstract: A hybrid air conditioning system which simultaneously dehumidifies and cools air using standard vapor-compression equipment and aqueous solutions of liquid desiccant. By using a circulating liquid desiccant and an adiabatic humidifier, a more efficient refrigerant cycle is utilized. Moreover, conditioned air can be delivered at the same temperature and absolute humidity as conventional vapor-compression systems but without overworking the compressor.

Predicting Gas Turbine Performance Degradation Due to Compressor Fouling Using Computer Simulation Techniques

Abstract: Etude par simulation sur ordinateur de la degradation des performances d'une turbine a gaz du fait de l'encrassement du compresseur

Method and apparatus for preventing surge in a dynamic compressor

Abstract: A method is disclosed for efficiently protecting dynamic compressors from surge under changing inlet conditions and in response to flow disturbances of varying size and speed. An antisurge control system based on this disclosed method will compute the relative proximity of the compressor operating point to its surge limit as a multi-variable parameter which is self-compensated for changes in gas composition, inlet temperature and pressure, compressor efficiency, guide-vane position, and rotational speed. A combination of adaptive closed- and open-loop control responses is used to maintain a margin of safety between the operating point and the surge limit. Both the safety margin and the magnitude of the open-loop response are proportional to the rate at which the operating point approaches the surge limit, thus maximizing process efficiency.

High pressure ratio turbocharger

Abstract: A turbocharger for an internal combustion engine can provide a two-stage compressor with movable stator blades to shift the compressor performance and match the air output of the turbocharger to varying air requirements of an internal combustion engine. The turbocharger can also be provided with a generally optimum boost pressure ratio of about 4.5:1 to 4.6:1. Such a compressor comprises a first axial-compressor stage, typically providing a 1.3:1 pressure boost ratio, and a second radial-compressor stage, typically providing a pressure ratio of 3.5:1. The turbine of such a turbocharger can be a combination flow turbine and can be provided with closure means to vary the turbine geometry and provide more efficient turbine operation at low-engine speeds. The turbocharger includes a roller bearing system adapted to accommodate imbalance. A control system operating in response to engine-operating conditions can operate the compressor-stator vanes and, if present, the turbine closure means.

Fuel cell power generation system

Abstract: In order to improve the efficiency of a fuel cell power generation system and its ability to adjust to disturbing factors which may occur during operation, a motor driven compressor for providing reaction air to the fuel cell system is driven independently of a power recovery system which recovers energy lost in operational by-products and converts the energy into electrical power. The independent motor driven compressor provides a stable supply of reaction air to the fuel cell and aids in shortening the time necessary for system start up.

Segmented seal plate for a turbine engine

Abstract: The clearance between a seal assembly (48) and a turbine wheel (16) in an engine of the type having a radial outflow compressor (24) and a radial inflow turbine (16) is minimized by forming the seal assembly (48) in part out of a plurality of segments (74) disposed in a circular array and which are relatively movable but sealed to each other. The thermal stress in the segments (74) will be less than in a single ring resulting in an extended life before the onset of cracking and eventual mechanical failure.

Method for controlling a motor vehicle air conditioning system

Abstract: A method for controlling a motor vehicle air conditioning system is described. The motor vehicle air conditioning system comprises a refrigeration circuit including a refrigerant compressor, a condenser, an evaporator and a throttle device arranged upstream of the evaporator. The condenser is associated with a ventilating fan and the evaporator is associated with a blower. The compressor capacity, the condenser capacity and the evaporator capacity are directly or indirectly sensed by sensor means and supplied as electrical variables to an electronic control circuit which logically combines these input signals and generates output signals in dependence on at least two of these capacity values and including further parameters. The control circuit acts on electrically controllable acturators for influencing the compressor capacity, the condenser capacity and/or the evaporator capacity.

High bypass turbofan engine having a partially geared fan drive turbine

Abstract: The present invention provides a high bypass turbofan engine configuration wherein a fan drive turbine is divided into first and second turbine sections mounted for independent rotation within the engine frame. The first, higher pressure, higher speed turbine section is coupled to the fan section drive shaft via a gear box which reduces the rotational speed of the power delivered by the higher pressure first turbine section to match the design rotational speed of the fan section. The second turbine section, having a larger diameter and lower rotational speed as compared to the first turbine section, is directly connected to the fan section and drives the fan section at the same rotational speed as that of the second turbine section. In this manner, the fan drive shaft horsepower is provided while reducing the weight and size of the necessary gearing between the fan drive turbine and the fan. The weight and size of the fan drive turbine and the booster compressor are also reduced.

Compressor system with demand cooling

Abstract: A refrigeration system is disclosed which incorporates apparatus for preventing overheating of the compressor by selectively feeding liquid refrigerant from the outlet of the condenser to the compressor. In one embodiment the refrigerant fluid from the compressor is injected into the suction manifold of the compressor. In another embodiment this fluid is injected directly into the compression chamber or chambers. Control means are provided which include a temperature sensor located within the compressor discharge chamber and valve means responsive thereto to control the flow of liquid refrigerant to the suction manifold or compression chamber.

Air conditioner for railway vehicles

Abstract: A flat air conditioner for railway vehicle for installation on the roof of a vehicle is advantageous from the viewpoint of reducing air resistance to the vehicle and the design of the vehicle. The present invention provides such a vehicular air conditioner incorporating an horizontally longer compressor or compressors disposed with the longitudinal axes in a horizontal plane or disposed in a return air chamber to construct the air conditioner in a flat configuration with a small height and in a compact construction.

Control apparatus for air conditioner

Abstract: An air-conditioner comprises a refrigerating circuit having a compressor, a condenser, an expansion device and an evaporator which are connected by suitable refrigerant conduits. An electric current path for making a current flow through the compressor includes an AC power source, to which a current transformer is coupled, and an output of the current transformer is converted into a DC voltage which is then given as a (+) input of a comparator. A reference voltage is given to a (-) input of the comparator. When the DC voltage exceeds the reference voltage of the comparator, the high level is outputted from the comparator. When the high-level output from the comparator persists for three seconds, the compressor is stopped forcedly and a three-minute timer is turned on. After a lapse of three minutes, the flow of the current through the current path of the compressor is resumed. Thereby, a lightly locked state is removed. If the output of the comparator still remains at the high level when the energizing is resumed, the compressor is put in the stopped state again. When such stopping and resuming of energizing of the compressor are repeated four times, the energizing of the compressor is stopped assuming that the compressor is in a heavily locked state.

Ericsson cycle machine

Abstract: An Ericsson cycle machine is disclosed which can be used for refrigeration, liquefaction of nitrogen or as an engine. The invention includes a liquid ring compressor linked to a liquid ring expander by a gas loop that includes a recuperator. As a refrigeration unit, the liquid ring in the compressor is channeled through a heat exchanger to reject waste heat and liquid is tapped from the expander liquid ring and used as a refrigerant.

Turbocharged compound cycle ducted fan engine system

Abstract: A turbocharged, compounded cycle ducted fan engine system includes a conventional internal combustion engine drivingly connected to a fan enclosed in a duct. The fan provides propulsive thrust by accelerating air through the duct and out an exhaust nozzle. A turbocharger is disposed in the duct and receives a portion of the air compressed by the fan. The turbocharger compressor further pressurizes the air and directs it to the internal combustion engine where it is burned and exits as exhaust gas to drive the turbine. A power turbine also driven by exhaust gas is also drivingly connected through the engine to the fan to provide additional power. The size and weight of the turbocharger are reduced since the compressor's work is partially achieved by the compression effect of the fan. The total propulsive thrust includes the fan generated thrust which bypasses the turbocharger and the thrust of exhaust gases exiting the turbine.

Turbofan engine having a counterrotating partially geared fan drive turbine

Abstract: A high bypass ratio turbofan engine having a fan section, a booster compressor disposed aft of the fan section relative to the flow of combustion gases through the engine, and a core section disposed aft of the booster compressor. A low pressure counterrotating turbine, disposed aft of the core section, is used for driving the fan section and the booster compressor. The counterrotating turbine includes at least one set of rotating turbine blades and at least one set of oppositely rotating counterrotating turbine blades. A twin spool shaft is provided for coupling the turbine blades to the booster compressor and for coupling the counterrotating turbine blades to the fan section. A reduction gear is disposed in the drive shaft for coupling the turbine blades to the fan section and for reducing the rotational speed of the turbine output power to match the rotational speed of the fan section thereby splitting the usable work of the turbine blades between the fan section and the booster.

Auxiliary air conditioning apparatus and method for air conditioned vehicles

Abstract: An auxiliary air conditioning system is provided for vehicles having a primary air conditioning system. The vehicle's primary air conditioning system includes a primary compressor powered by the vehicle engine through a suitable mechanical linkage, a primary condenser, a primary evaporator and blower, and a cooled air distribution system. A preferred auxiliary air conditioning system, according to the invention, is incorporated into the primary air conditioning system and adapted to provide refrigerated air conditioning when the primary compressor and vehicle engine are not operating. One preferred auxiliary air conditioning apparatus includes an auxiliary compressor powered by an auxiliary compressor electric motor, and an auxiliary condenser and electric powered condenser fan. The auxiliary compressor is connected for receiving evaporated refrigerant from the primary evaporator, compressing the refrigerant, and delivering the compressed refrigerant to the auxiliary condenser for condensing. A control system prevents the operation of the auxilary compressor when the vehicle engine is on. The auxiliary condenser is connected to deliver condensed refrigerant to the primary evaporator where the refrigerant is evaporated to provide cool air to be distributed similarly to the primary air conditioning system. In alternate forms of the invention, the auxiliary air conditioning system may be a complete separate system including an auxiliary evaporator and blower that is separated from the auxiliary compressor and condenser. The separated auxiliary air conditioning components are positioned on or inside the vehicle so as not to affect the vehicle aerodynamics and vehicle height.

Gas refuelling device and method of refuelling a motor vehicle

Abstract: The gas refuelling device for a motor vehicle comprises a compressor unit, a gas distributor unit and a control unit inside a housing and an external operating unit. At least one temperature sensor and one pressure sensor deliver measured values to the control unit, which has stored set values which are adapted to the changing environmental and operating conditions. When actual values deviate from their set values, the operating state of the gas refuelling device is altered. The operating states are selected such that the device closes down if there are serious incorrect manipulations or components fail and can only be made ready for operation again with auxiliary devices.

System for cooling in a gas turbine

Abstract: A gas turbine is provided in which the quantity of cooling air required to cool the turbine is reduced by the evaporative cooling of air bled from the compressor discharge for cooling purposes. The evaporative cooling is accomplished by spraying pressurized water into a bleed pipe which diverts the cooling air from the compressor discharge to the turbine.

Active clearance control

Abstract: The invention relates to a control system which controls the diameter of a turbine shroud which surrounds a turbine in a gas turbine aircraft engine. The invention seeks to minimize the clearance (33) between the turbine rotor blades (123) and the shroud (36). Air is bled from the compressor (18) in the engine and ducted (98,112) to the shroud in order to heat or cool the shroud in order to, respectively, either expand or shrink the shroud to a proper diameter. The air temperature which is required is computed based on compressor speed and other engine parameters, but not necessarily upon rotor temperature as such, despite the fact that rotor temperature has a significant influence upon rotor diameter, and thus upon the shroud diameter needed. In a preferred embodiment, air at two different temperatures is bled from two different compressor stages (83,89) in the engine and mixed together (98) in a ratio which is determined (by valve 94) according to flight conditions, in order to provide air of the required temperature for the shroud, and then ducted to the shroud in order to modify shroud size. Further, during accelerations and decelerations of the engine, a different air temperature is provided, as compared with that provided during steady state operation. In the event of system failure shroud diameter can be controlled by back up systems, e.g. one for use during steady state, and the other for use during accelerations and decelerations.

Rotary displacement compression heat transfer systems incorporating highly fluorinated refrigerant-synthetic oil lubricant compositions

Abstract: A rotary displacement compression heat transfer system and method for improving its efficiency includes a rotary displacement compressor for compressing a refrigerant, a condensor connected with the outlet of the compressor, an evaporator connected with the inlet of the compressor, an oil pump for injecting oil into the compressor, an oil separator for separating out the oil and recirculating it to the compressor, a non-chlorinated fluorinated refrigerant, and a synthetic oil providing an inverse solubility characteristic where a mixture of the refrigerant and oil has two immiscible phases in the compressor's operating temperature range at a weight concentration of oil in the range of about 10-60% and has only one dissolved liquid phase at a temperature in the evaporator's operating range at a weight concentration of oil less than about 5%

Gas compressor having dry gas seals

Abstract: A gas compressor, particularly of the kind for boosting pressur in gas transmission lines, has an impeller (30) mounted on a shaft (22) located between two bearings (24) with the gas space (40) surrounding the impeller (30) being separated from the bearings (24) by dry gas seals, including at least primary dry gas seals (52a, 52b, 54a, 54b). The primary dry gas seal (52b) adjacent the discharge end (14) of the compressor is of larger diameter than the corresponding seal at the inlet end (12) of the compressor so that pressurized gas acting on the respective rotary parts of the dry gas seals urges the shaft (22) towards the discharge end (14) of the compressor and thus counteracts dynamic forces on the impeller (30).

Stall Inception in Axial Compressors

Abstract: Detailed measurements have been made of the transient stalling process in an axial compressor stage. The stage is of high hub-casing ratio and stall is initiated in the rotor. If the rotor tip clearance is small stall inception occurs at the hub, but at clearances typical for a multistage compressor the inception is at the tip. The crucial quantity in both cases is the blockage caused by the endwall boundary layer. Prior to stall disturbances rotate around the inlet flow in sympathy with rotating variations in the endwall blockage; these can persist for some time prior to stall, rising and falling in amplitude before the final increase which occurs as the compressor stalls.Copyright © 1989 by ASME

Dehumidifier for waveguide system

Abstract: A dehumidifying system uses a membrane cartridge to filter water vapor from air or other gas introduced into the membrane cartridge via a main pump or compressor. Dehumidified gas from the membrane cartridge is then delivered into a system which requires dry gas. The dehumidifying system further includes valve arrangements or additional compressors which provide gas flow through the membrane cartridge when the main compressor is inactive. Therefore, the membrane cartridge receives a substantially continuous flow of gas which maintains the optimal efficiency of the membrane cartridge. In addition to the arrangements which provide this continuous gas flow, a heating coil wrapped around the membrane cartridge raises the temperature of the fiber membranes within the cartridge. The heated fiber membranes are less susceptible to retain moisture which decreases the efficiency of the membrane cartridge.

Compound power plant

Abstract: The invention is a compound motor having an internal combustion engine, a turbine driven by exhaust from the engine and compressor connected to the turbine. The compound motor has a clutch means to declutch the compressor from the turbine and to disable the turbine from transferring power to a gear set. The gear set is capable of simultaneously receiving power from the engine and the turbine and transferring this power to a final output shaft. The clutch mechanism brake or debrakes, and clutches or declutches, in response to torque or rotational force exerted on the turbine by the exhaust gas from the engine.

Mounting mechanism for an automotive air conditioning compressor

Abstract: A mounting mechanism is disclosed, which connects a compressor of an automotive air conditioning system to an automobile engine through a mounting bracket. A bolt-nut mechanism connects the bracket to a flange portion projecting from the outer peripheral surface of the compressor. The bolt penetrates holes formed through the bracket and flange portions and an axial vibration absorbing unit disposed in either one of the holes. The absorbing unit includes an elastic member to absorb the axial vibration of the compressor. Coupling members connect between the mounting bracket and the compressor and are axially movable but not radially movable.

Method and system for controlling variable compressor geometry

Abstract: A method and system for controlling the position of a variable pitch vane stage (34) in a gas turbine engine (10) uses a feedback loop comparing the current compressor pressure ratio to a reference compressor pressure ratio. The reference pressure ratio is determined from a plurality of current engine operating parameters which identify a unique point on the compressor operating line.

Automatic air conditioning system with variable displacement compressor for automotive vehicles

Abstract: An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprises a sensor for detecting an intake air temperature, defined by a temperature of air flowing through an evaporator, placed just behind the evaporator, an intake pressure sensor for detecting an intake manifold pressure, and a CPU for determining whether the cooling requirements of the evaporator are satisfied on the basis of the intake air temperature compared to a predetermined value. The CPU controls the compressor in such a manner that the discharge volume of refrigerant discharged from the compressor is decreased only when the cooling requirements are met. Thus, the automatic air conditioning system prevents uncomfortably warm conditioned air from being discharged through a vent door under acceleration conditions.

Method and equipment for obtaining energy from oil wells

Abstract: Pressurized petroleum flows from a well into a turbine. The petroleum undergoes a pressure reduction in the turbine and then enters a separation chamber where it is separated into liquid and gaseous phases. The liquid phase is sent to a pump which serves to transfer the liquid phase to a station remote from the well. Similarly, the gaseous phase is directed to a compressor which functions to transfer the gaseous phase to a station remote from the well. The pump and the compressor are coupled to the turbine which uses the energy liberated by the petroleum during pressure reduction to drive the pump and the compressor.