Liquid ring vacuum pump working principle of led
From the outside, the NASH vacuum pump only hints at how it's internal parts liquid ring vacuum pump working principle of led. Shaft bearings on heavy cast iron brackets are easily accessible for servicing. The top connection of the pump is the inlet, while the side connection is its discharge some NASH pumps do have a different orientation.
The NASH liquid ring vacuum pump uses water or any other suitable liquid, which acts as "liquid pistons", hence the name liquid ring. It's apparent that the chambers between the rotor blades, shown here in yellow, are open around the periphery. The chambers are open on the inside, as well.
These inner edges of the rotor blades are machined to rotate around the cone surface, shown in redwith a close non-contact fit. An internal passage joins the openings from the pump inlet to an inlet port in the cone. There's also a passage from the cone discharge to the discharge connection on the head.
Some NASH pumps have a port plate configuration rather than conical, but the principle is the same. This diagram demonstrates what the rotor and body do while the pump is in operation.
The spinning of blue liquid forms a ring due to centrifugal force. Because the rotor axis and body axis are offset from each other, the liquid ring is not concentric with the rotor. Air or gas traverses the internal passage to the cone inlet port. As the white dots indicate, the gas is drawn into the rotor chambers by the receding liquid ring, similar to the suction stroke of a piston in a cylinder. The liquid ring does the job of pistons, while the rotor chambers play the part of cylinders.
As each chamber rotates past the inlet port, the chamber carries a volume of air or gas around with it. Liquid ring vacuum pump working principle of led white dots are confined between the cone and the ring of rotating liquid.
The gas is compressed liquid ring vacuum pump working principle of led the liquid ring converges with the cone. This represents the compression of air or gas from vacuum up to atmospheric pressure, or from atmospheric up to positive pressure in a liquid ring compressor.
When each chamber rotates to the discharge port opening, the compressed air or gas escapes from that chamber through the discharge port to the internal discharge passage.
Air or gas, with the dots closely packed to indicate higher pressure, is shown here flowing out of the discharge connection at right. The flow is continuous without pulsation. In this completed schematic, the entire vacuum pumping cycle is shown.
Here air or gas entering the NASH pump is shown as white dots at the inlet connection. This represents the compression of air or gas from vacuum up to atmospheric pressure, or from atmospheric up to positive pressure in a liquid ring compressor Discharge 9. Learn more about the liquid ring principle from Nash, the original liquid ring innovator.
From the outside, the vacuum pump only hints at how it's internal parts function. Shaft bearings on heavy cast iron brackets are easily accessible for servicing. The top connection of the pump is the inlet, while the side connection is its discharge some pumps do have a different orientation. The liquid ring vacuum pump uses water or any other suitable liquid, which acts as "liquid pistons", hence the name liquid ring. It's apparent that liquid ring vacuum pump working principle of led chambers between the rotor blades, shown here in yellow, are open around the periphery.
The chambers are open on the inside, as well. These inner edges of the rotor blades are machined to rotate around the cone surface, shown in redwith a close non-contact fit. An internal passage joins the openings from the pump inlet to an inlet port in the cone. There's also a passage from the cone discharge to the discharge connection on the head.
Some pumps have a port plate configuration rather than conical, but the principle is the same. This diagram demonstrates what the rotor and body do while the pump is in operation. The spinning of blue liquid forms a ring due to centrifugal force. Because the rotor axis and body axis are offset from each other, the liquid ring vacuum pump working principle of led ring is not concentric with the rotor.
Air or gas traverses the internal passage to the cone inlet port. As the white dots indicate, the gas is drawn into the rotor chambers by the receding liquid ring, similar to the suction stroke of a piston in a cylinder. The liquid ring does the job of pistons, while the rotor chambers play the part of cylinders. As each chamber rotates past the inlet port, the chamber carries a volume of air or gas around with it.
The white dots are confined between the cone and the ring of rotating liquid. The gas is compressed as the liquid ring converges with the cone. Liquid ring vacuum pump working principle of led represents the compression of air or gas from vacuum up to atmospheric pressure, or from atmospheric up to positive pressure in a liquid ring compressor. When each chamber rotates to the discharge port opening, the compressed air or gas escapes from that chamber through the discharge port to the internal discharge passage.
Air or gas, with the dots closely packed to indicate higher pressure, is shown here flowing out of the discharge connection at right. The flow is continuous without pulsation. In this completed schematic, the entire vacuum pumping cycle is shown. Industries Segments Our Brands. About News Investors Careers. Here air or gas entering the pump is shown as white dots at the inlet connection.
Liquid ring compressor, characterized by an eccentric inner rotor 6 is supported in axles 8, 9 to an outer co-rotor 3 for the liquid ring, where the bearing of the co-rotors 11 is outside the same axles on each side is enclosed in an enclousure where it on each sides of the bearing 11 is arranged a rotating lip seal 82 which lip 83 abut the axles 8, 9 at low speed, and which at high speed is projected due to centrifugal forces out and lifts itself from the axles, where through holes 81 through the co-rotor's sidewalls and bearing enclosure, its volume within the liquid ring is aired to the surrounding enclosure 1and ensures that it is not created a differential pressure across the bearings and the seals of the bearings.
The present invention relates to a compressor, in particular a liquid ring compressor. Most compressors work with approximate adiabatic process, i. A turbo compressor often has very close adiabatic process.
Some, a bit more special compressors can work very close to isothermal, i. Examples of these are water driven ejectors and liquid ring compressors, where both are frequently used with vacuum. A screw compressor with oil injection works polytropic, i. The isothermal process requires less energy supplied than the adiabatic. The difference increase rapidly with increasing pressure difference, as shown in the diagram in FIG. This shows theoretical values, calculated for air based upon formula for ideal gas.
Air and gases which in a state which is not in the proximity of the critical point, behave very close to ideal. For most objectives it is not desirable with hot gas after compression, and from this and the energy consumption, the isothermal process is preferred liquid ring vacuum pump working principle of led theory. When this, despite the above, is not employed today, the reason can be found in that existing isothermal or close isothermal compressors have too large hydraulic and dynamic losses.
These can operate with low peripheral speeds on the liquid ring. Another problem is in the technical challenge to be able to remove heat continuously during compression. Within vacuum both ejector and water ring compressors are frequently used. An ejector exploit the mass speed in a water liquid ring vacuum pump working principle of led in which the cross section expands and thereby can pull another medium with it.
The ejector transform dynamic pressure to static pressure. However, an ejector system has relatively high losses in pump, in nozzle, by impact and friction. Ejectors are rarely used to anything else than the vacuum field. Within prior art the water ring compressor is closest to the compressor according to the present invention.
A liquid ring compressor consists mainly of an impeller which rotates eccentric in an outer enclosure together with a ring of water which the centrifuigal force keeps in place against the periphery. The inlet is normally positioned as an opening in one or both of the end walls of the enclosure where the gas is drawn into the gaps of the impeller.
Accordingly, it is arranged openings in the end walls on the pressure side, where the compressed gas is pushed out. All the types can have stationary commutators arranged centrally within the rotor where inlet and discharge happens radially. Liquid ring compressor does not transform the energy in the water in the same way as the ejector. The static pressure in the ring of water remains constant.
The ring liquid ring vacuum pump working principle of led water acts as a piston in every cell of the rotor. The principle for an ordinary liquid ring compressor is shown in FIG. The static pressure in the ring of water has to be the same as the compression pressure, otherwise the water will be pressed out of the cell, i.
Thereby it is given that a certain pressure height, p2-p1, require a minimum centrifugal force. A liquid ring compressor usually has considerably higher pressure height and therefore requires higher speed of rotation than a vacuum pump. The highest loss of friction in a conventional water ring compressor arise when the rotor is touching the wall of the enclosure.
The clearing must here be very small, something which involves the water against the enclosure's periphery to have the same speed as the impeller tips of the rotor.
Furthermore it must be very little clearance between the sides of the rotor and the enclosure. Also in these gaps there will be high frictions. Generally the friction losses increase with a square of the speed increase, and in practice the water ring compressor looses level of energy in relation to energy in relation to an adiabatic compressor even at relatively low pressure ratios. Without these friction losses, the liquid ring compressor has many advantages.
It is very simple and can be one stage up to relatively high pressure ratios. It is apparent that if that the enclosure around the ring of water rotated together with this, the hydraulic friction losses would be minimal. Thus, such a compressor would for normal pressure ratios could exploit the isothermal energy advantages almost in full.
An earlier suggestion disclosed with an outer, rotating cylinder tried to solve the problem of friction, without this leading to a feasible solution. By floating on a liquid film, it is doubtful whether it would be achieved any liquid ring vacuum pump working principle of led in the friction, and with gas it would probably not be possible to achieve sufficient bearing capacity and stability, such that the cylinder do not touch the enclosure.
In a later patent, U. This do not seem realistic with the actual rotational speeds the rollers will achieve. A subsequent patent, U. This publication indicates a bearing of the outer rotating cylinder on one side and the rotor on the opposite side, where a stationary plate close to the open end of the rotor has canals for inlet and discharge.
It is mainly two decisive weaknesses with this design. The first is the one-sided bearing this solution gives, where the bearing load becomes uneven and too high. At the same time large axial thrust forces arise. The other weakness is the problems with achieving a reasonable gas tight sealing between the outer rotating cylinder, and the plate where the inlet and discharge canals are positioned in a circular plate, inlaid in the open end of the rotor.
It would here be gas leaks backwards from cell to cell and in addition out through the circular gap between the stationary plate and the rotor. The principle is unrealistic for practical purposes. Despite may studies and suggestions over many years, it evidently has not been possible to reach a design which fulfil the requirements to function satisfactory.
Thus at present there exists no liquid ring compressor with such co-rotating rotor. The above mentioned publications indicates that one has been tied up to the starting point for a rotor and communicator system like those in conventional vacuum pumps and compressors for relatively low pressure, with the above mentioned limitations in speed.
This is reflected in relatively wide rotors with communicator on each side, which lead to long bearing distance and high bearing loads. In a compressor with liquid ring in the outer co-rotor, the geometry will be wrong, which will liquid ring vacuum pump working principle of led to bearing relationship which is unsuitable for existing bearing types.
With communicator on each side it becomes four sections with gaps liquid ring vacuum pump working principle of led there exists leakage from the zones on the pressure side.
The compressor according to the present invention has the objective to solve liquid ring vacuum pump working principle of led problem which up to know has prevented a water ring compressor to exploit the above mentioned advantages with a co-rotor for the liquid ring. Another objective is to achieve almost isothermal compression with a new, very efficient direct injection of liquid into the gas during the whole compression stage.
Water as injection liquid has very good thermal properties, and is desirable to use with those gases which allow this. But, as for pumps and the like, the design for a liquid compressor with a co-rotor require a distinct division between water and the bearing of the co-rotor.
From the development of screw compressors with water injection it is known and it has been problems with sealing on the pressure side of the screws. Firstly, water has small to little lubricating effect on the sealing which must have relatively high pressure towards the axle and therefore high wear. Furthermore, water penetrates easily through even the finest gaps, and especially high pressure. Below it will be evident that the compressor according to the present invention solves the sealing problem by eliminating the reasons for them.
The aforementioned objectives will be satisfied with the liquid ring compressor according to present invention as it is defined in the attached claims.
The invention will liquid ring vacuum pump working principle of led be described, by way of example, with liquid ring vacuum pump working principle of led to the accompanying drawings, in which FIG. The main parts in FIG. In the sector II-III liquid is injected from the communicator directly into the rotor cells and the compression and cooling of the gas in the cells.
With the largely reduced friction in the water ring due to the co-rotor, is it possible to make the rotor considerable narrower at the same time that the discharge volume is compensated with a considerable increase in speed. Thereby the inner pressure in the water ring is increased and the compressor can deliver with very high pressure. A short rotor get little bending force from the gas pressure and is thereby allowed to be fixed to a flange on its axle only liquid ring vacuum pump working principle of led one end wall and thereby being able to have a simple commutator in the entire width of the rotor.
It is then only created two leakage gap between the commutator and the rotor. These gaps are the only place where leakage from the pressure side will find place. It can leak actually to both sides from the gap and along the periphery from the pressure discharge against the inlet, especially in the direction of rotation. Even in very small gaps, pure gas without liquid will with the present pressure be able to leak in considerable amounts, with smaller amounts deliver and lower efficiency as a result.
The surface of the rotor 6 on the inside towards the commutator is at its ends 63 smooth, with interweaving canal openings 62 to each individual cell. The grooves are under liquid pressure from the liquid canal 74 which thereby liquid ring vacuum pump working principle of led blocking for gas leakages in the actual direction. The liquid ring compressor according to the present invention could be designed with hydro dynamic bearing for the co-rotor. These could then be lubricated and cooled with the same liquid which was used for injection.
But with the starting point with necessary axle diameter and speed, research shows however that the friction losses in such bearings then will be very high and some of the advantages with a co-rotor are lost. With higher pressure the bearing size increases further and the losses in them become unacceptable.
On the other hand the same relationship seems to be acceptable for relatively large ball or roller bearings, but at the same time this leads to new problems around the bearing sealing. Bearings with integrated seals can not operate close to the necessary speeds and there do not exist any static seals which allows this, or that will achieve acceptable lifetime. Labyrinth seals however are touch-free and can operate with high speeds, but do not give any static sealing. These seals assume there are no differential pressures across the seal.
To prevent differential pressure across the bearing a co-rotor is aired to the compressor enclosure through the holes 81 as shown in FIG. For air pressure compressors the enclosure is in turn aired to atmosphere or is by compression of other gases to prevent discharge, aired to the inlet, and thereby it will not be a differential pressure across the bearing of the co-rotor.
Blocking liquid which leaks from the gap between the commutator and the rotor will during operation be projected out into the liquid ring and will not be able to reach the bearings for the co-rotor.
Thus, the design only needs a static bearing seal during the stopping phase, where the danger for splashing water against the seals is apparent when the water ring collapses due to lack of centrifugal force. In conventional water ring compressors it is earlier known to be used lip seals as disclosed in U. In that case, however, it is dealt with a drive axle which has a relatively small diameter and low peripheral speed. As mentioned above the speed relationship for the co-rotor becomes critical with regards to wear.
This is led to the liquid ring vacuum pump working principle of led for designing and completely new lip seal 82shown in more detail in FIG. The seal rotates together with the outer ring of the bearing The liquid ring vacuum pump working principle of led 83 is relatively ductile and at standstill and under start and stop cycle it will rest against the axle and seal statically, but when the speed and centrifugal forces increases, it is projected outwards and get a clearance sx so it does not touch the axle during operation.
It is evident that the lip during operation places itself against the edge of the openings in the co-rotor and walls so it is relatively small movements the lip bends from being in contact with the axle until it is not.