CZ2019732A3 - A method of carrying out a compression cycle and a gear or screw compressor for this - Google Patents

Abstract

In a compression cycle in a gear or screw compressor, the compression of the gas in the working space is performed polytropically with a compression ratio which varies according to the gas pressure in the discharge space or is constant or adjustable in the first part of the compressor operating range and in the next part of the compressor operating range. gas pressure in the discharge space. The gear or screw compressor comprises a path for expelling compressed gas from the working space, which is separated from the working space by at least one discharge valve.

Description

A method of performing a compression cycle and a gear or screw compressor for performing the method

Field of technology

The invention relates to a method of carrying out a compression cycle in a gear or screw compressor, which comprises sucking gas into the working space, a polytropic compression operation of the gas in the working space and an operation of expelling compressed gas from the working space into the discharge space. The invention further relates to a compressor for carrying out this method.

Prior art

Gear compressors or screw compressors have two rotors with two or more teeth and have individual working spaces defined by the inner contour of the compressor body and the gaps between the adjacent teeth of the interlocking rotors. By the mutual engagement of the rotors, one common working space is created from each interconnected pair of working spaces from one and the other rotor. At the connection point of the suction and discharge ports, the inner contour of the compressor body is interrupted and the working spaces of the rotor are open for suction, resp. gas extrusion.

The discharge opening is located axially in the case of a gear compressor and is located radially, axially or in combination in the case of a screw compressor.

These gear or screw compressors are formed with a constant fixed or built-in compression ratio, i.e. the gas is polytropically compressed after suction in the working space of the interlocking rotating rotors until the compressor working space is connected to the discharge nozzle space. spaces is constant in a given compressor.

Ideally, at the time of connection of these spaces, the pressure in the working space of the compressor should be the same as the pressure in the discharge space, i.e. in the discharge port and the discharge line, and theoretically the gas discharge into the discharge line should continue continuously.

In practice, however, the pressure in the discharge space is different than in the working space, and the mixing of gases in these spaces takes place first.

If the gas pressure in the discharge space has to be kept even slightly higher than the gas pressure in the working space of the compressor, shock external compression occurs, ie the gas in the working space is compressed by the gas from the discharge space. Conversely, if the gas pressure in the discharge space is lower than the gas pressure in the working space of the compressor, a throttling occurs, i.e. a sudden expansion of the gas from the working space of the compressor to the value of the pressure in the discharge space. These phenomena reduce the efficiency of the compression cycle.

It is only after this mixing that the compressed gas is discharged into the discharge line.

In both screw and screw compressors, the efficiency of the compression cycle is also impaired by the fact that part of the compressed gas at the end of the discharge is passed between the rotors from the discharge side to the suction side of the compressor working spaces due to imperfect tooth shape.

Another disadvantage of this method of gas compression is the noise of pulsations during a sharp, sudden change of the flow direction.

Impact external compression during discharge and the transfer of compressed gas into the suction are the cause of relatively large energy losses and the cause of higher temperature of the extruded gas than corresponds to

- 1 CZ 2019 - 732 A3 theoretical compression.

In the case of screw compressors, it is solved that the fixed compression ratio can be mechanically adjusted to a large extent by means of a sliding control slide on the discharge side, thus minimizing the degree of external compression at variable values of the pressure in the network.

The price for the relative simplicity of the compression method, i.e. achieving the resulting pressure by external compression or the built-in compression ratio, is the reduced economy of compression in these compressors or the limited possibility of changing the pressure level in the appliance network.

A discharge valve is normally located in the discharge line as a non-return valve to prevent the compressed gas from moving back to the compressor when it is taken out of service. It is usually located behind the discharge port of the compressor, so that the volume of gas in the space from the working space boundary to the discharge valve can be many times larger than the volume of discharged gas in the working space itself, so it has virtually no effect on compression efficiency in the compressor.

The basic object of the invention is to reduce the energy consumption of the compression cycle in gear and screw compressors.

The essence of the invention

The present invention solves this object by a method of performing a compression cycle in a gear or screw compressor, which comprises sucking gas into the working space, polytropically compressing the gas in the working space and expelling compressed gas from the working space into the discharge space. The essence of which is that the compression of the gas in the working space is performed polytropically with a compression ratio which varies throughout the compressor operating range according to the gas pressure in the discharge space or the phenomenon of the first part of the compressor operating range is constant or adjustable and in the next part of the compressor operating range changes according to the gas pressure in the discharge space.

In essence, compression in a screw or gear compressor takes place in such a way that the sucked gas is compressed by reducing the closed working space, i.e. generally polytropically, with a compression ratio which varies according to the gas pressure in the discharge space. Depending on the design of the compressor, this happens smoothly and almost immediately.

The operating range of the compressor is the range of pressures for which the compressor is built.

In this case, the polytropic compression of the gas takes place in such a way that the entire polytropic compression takes place according to the gas pressure in the discharge space, which is an advantageous option for conditions where the pressure in the discharge space is variable and cannot be guaranteed to fall below a certain value.

In the following variant, part of the polytropic compression takes place in such a way that the first part of the compression takes place with a constant or adjustable fixed compression ratio and the rest of the polytropic compression takes place according to the gas pressure in the discharge space, which is an advantageous option for conditions where the pressure in the discharge space is variable. higher than corresponds to a constant or adjustable fixed compression ratio.

In no case is there external compression by gas from the discharge space - during compression, the backflow of compressed gas from the discharge space into the working space is prevented.

-2 CZ 2019 - 732 A3 space with discharge pipe and discharge nozzle.

Advantageously, part of the compression of the gas in the working space can be performed by supplying the compressed gas directly to the working space, in a different way than the way for expelling the compressed gas from the working space into the discharge space.

The path for expelling compressed gas from the working space to the discharge space contains not only the discharge line but also the discharge port.

The supply of compressed gas directly to the working space in a different way than the way for expelling the compressed gas from the working space into the discharge space is hereinafter also referred to as pressurization.

If the compressed gas is fed directly into the working space in a different way than the way for expelling the compressed gas from the working space into the discharge space, this means that the compressed gas is fed into the working space by any route but not back from the discharge space. discharge line, but also from the discharge port.

The pressure of the compressed gas supplied directly to the working space in a different way must be higher than the pressure of the gas in the working space.

It follows from the invention that the compressed gas (i.e. the make-up gas) used to supply directly to the working space for compressing the gas already present in this space can be taken from the compressor's own discharge space or can be supplied from an external source, and obtaining a gas mixture can be, for example, a technological purpose.

It also follows from the essence of the invention that the compression cycle can advantageously also be used in vacuum operation. If the working gas is air, then it can be compressed to atmospheric pressure and the discharge space can be the ambient atmosphere.

Advantageously, the compressed gas can be cooled before being introduced into the working space. According to the invention, at least that part of the expelled gas which is used for compressing the suction gas is cooled and only then is introduced into the working space. This lowers the discharge gas temperature and the compressor temperature. Cooling increases the density of the gas used to compress (push) the sucked gas, which somewhat increases the energy consumption of the compression cycle.

However, the heat obtained by cooling the compressed gas supplied to the working space by compression can advantageously be used for practical purposes, preferably for heating and / or for conversion to electrical energy, thus reducing the overall energy consumption by compression.

Advantageously, the flow of compressed gas supplied to the working space can be regulated. When changing the suction quantity and the overpressure of the gas, by supplementing the flow of compressed gas supplied to the working space according to the invention, it is possible to adapt the replenishment (pushing) of the working space with compressed gas so that it is spread over as long as possible.

To further reduce pressure and flow non-uniformities, it may be advantageous to accumulate the expelled gas.

The differentiation of the paths for supplying compressed gas directly to the working space and for expelling compressed gas from the working space can advantageously be realized in gear and screw compressors in such a way that compressed gas is supplied to the working space of the first rotor via a separate external path and / or from an adjacent working space. rotom.

In the screw compression, in the region of the discharge port, compressed gas from the working chamber of the deep rotor is fed into the working space of the given rotor after the previous compression cycle.

-3 CZ 2019 - 732 A3

If compressed gas from the discharge space is used for boosting, the discharge and boosting pipes, including any air tanks and heat exchangers, have a substantially larger volume than the volume of one compressor working space. By pressing it, it is then possible to compress the sucked gas practically to the value of the pressure in the discharge line.

The invention also relates to a gear and screw compressor comprising a path for sucking gas into the working space and a path for expelling compressed gas from the working space, the essence of which is that the path for expelling compressed gas from the working space is separated from the working space by at least one discharge valve.

In the case of a gear compressor, the path for expelling compressed gas from the working space can be separated from the working space by at least one forcibly controlled regulating discharge slide to adjust the compression ratio. Preferably, the slide will be located axially, from the side of the compressor body, where the planar surface allows a simpler solution for moving the closing plate and reducing the damage space.

Polytropic compression must overcome not only the gas pressure in the discharge space, but also the resistance of the discharge valve or slide, and only then can the gas be forced out of the working space into the discharge space, i.e. into the discharge port and further into the discharge line.

Removing the external compression will reduce gas flow unevenness, shocks and compressor energy consumption.

In order to minimize external compression and thus ensure economical operation of the compressor even at varying mains pressure values, the fixed, built-in compression ratio can be set to a large extent, regulated mechanically, preferably electronically, by means of a forced operated discharge valve or discharge valve, preferably regulating, preferably sliding.

Advantageously, the discharge valve of the compressor according to the invention can be automatic.

By separating the working space from the discharge space by means of an automatic discharge valve, the backflow of compressed gas from the discharge space into the working space, i.e. external compression of the gas in the working space of the compressor, is very effectively prevented.

In both gear and screw compressors, the path for sucking gas into the working space, i.e. the suction line and the suction nozzle, can advantageously be separated from the working space by at least one suction valve. Preferably, the suction valve is automatic.

In the compression cycle, the pressure energy of a part of the compressed gas can be used, which is transferred between the rotors from the discharge side to the suction side of the compressor working spaces at the end of the discharge due to the imperfect shape of the rotor teeth of the compressor.

If an automatic suction valve is used, the gas can be sucked into the gear compressor as follows:

- the suction port is connected to the working space of the compressor, the rotation of the rotors increases the volume of the working space, the suction valve is opened by the action of a vacuum in the working space and gas is sucked into the working space,

- the following closed working space formed between the teeth of the rotors and containing the remaining part of the compressed gas, which has not been forced into the discharge space, approaches the suction nozzle by turning the rotors,

-4 CZ 2019 - 732 A3

- by rotating the rotors, this subsequent closed working space is opened, the remaining part of the compressed gas is suddenly mixed with the sucked gas in the connected working space below the suction valve,

- when the compressed gas is mixed with the intake gas, the pressure in the connected working space increases and, as a result of the increased pressure against the gas in the suction port, the suction valve closes automatically,

- turning the rotors increases the volume of the working space and the gas in this space expands polytropically,

- further rotation of the rotors increases the volume of the working space and the created vacuum automatically opens the suction valve and the suction of gas into the working space continues.

The valve is forcibly actuated if the movement of the valve plate is mechanically or electronically derived from the movement of the rotors, and is controlled so that compressed gas is not supplied by the valve back into the working space back from the discharge space throughout the operating range of the compressor.

The valve is automatic if the movement of the valve plate is caused directly by the difference in gas pressures, preferably against the force of the spring.

Within this basic setting, the finer optimization of the opening and closing of the valve can be performed by secondary control, preferably according to the instantaneous pressure conditions in the gas network.

By analogy, these principles also apply to the slide valve.

The suction valve is located in the suction opening, the discharge valve is located in the discharge opening.

Preferably, the suction opening with the suction valve is moved to the area of the working space, where the pressure in the working space is equalized with the pressure in the suction space after the expansion of the transmitted compressed gas. This reduces the risk of compressed air expanding into the suction space.

It follows from the essence of the invention that the valve or the control slide is located in the opening directly on the boundary of the working space of the compressor.

By placing the valve in the hole as close as possible to the working space, the damage space is reduced, which reduces the efficiency of the compression cycle.

If the discharge or suction valve is oriented radially so that the discharge or suction is directed perpendicular to the axis of rotation of the rotors, i.e. the valve abuts the circumferential rotational surface of the rotors, it is advantageous if the contour surface of the valve on the rotor working space side , the valve can be called equidistant.

The design of the valve in the compressor can advantageously be such that the clearance between the valve and the rotors is of the same order of magnitude as the clearance between the compressor body and the rotors.

Advantageously, a plurality of discharge valves, preferably functionally independent of one another, can be arranged next to one another in the discharge or suction port of the compressor.

Increasing the number of valves along with reducing their dimensions reduces the unevenness of gas ejection or suction and minimizes gas penetration losses through the gaps between the valves and the rotor teeth.

Advantageously, the location of the discharge valves in the discharge port can be formed in an arc along the compression path of the working space.

- 5 CZ 2019 - 732 A3

This keeps the fixed part of the compression ratio to a minimum and the compressor can adapt smoothly to almost any change in the pressure conditions in the network while maintaining polytropic compression.

Similarly, the location of the suction valves in the suction port can also be formed in an arc along the suction path of the working space in order to ensure the best possible suction flow.

The discharge or suction openings are preferably located axially, on the side of the compressor body, so that the discharge or suction is directed parallel to the axis of rotation of the rotors.

If the valve is partially or completely covered by the rotor tooth as the rotor rotates, the balance of forces acting on the valve plate changes and the self-acting valve closes partially or completely. The stable valve therefore opens and closes each time it is covered by the rotor tooth.

This disadvantage is solved by an advantageous arrangement of the compressor, where the discharge and / or suction valves are connected to the rotor, so that they rotate together with it, i. that at least one separate discharge and / or suction valve is permanently available for each interdental working space. The valves are not overlapped by the rotor teeth and each valve rotates one opening and closing cycle at each rotor revolution.

For design reasons, the sidewall on both the discharge and suction sides of the compressor can always be equipped with rotary valves on only one of the rotors. However, this is not an obstacle to functionality, since the interconnected working spaces of the two rotors form a common working space, and therefore the sidewall of the second rotor can only be equipped with stable valves. Other design variants result from the possibility that the sidewall on the suction side does not have to be equipped with any suction valves, only suction openings, and that the sidewall on the discharge side does not have to be equipped with no discharge or valves, only discharge openings.

The rotary valves are preferably located in a separate disk which rotates in the side of the compressor and abuts the side of the rotors. A minimum clearance must be maintained between the rotating disk and the sidewall to allow the disk to rotate while preventing unwanted ingress of compressed or sucked gas.

According to a particular preferred embodiment of the compressor, openings can be formed in the sidewall or in the rotating disk, in which valves do not necessarily have to be located.

Preferably, the rotary valves are designed as lamellar valves. Preferably, the spring plates are mounted to the rotor on the inner radius of rotation and the valve plate on the outer radius of rotation to take advantage of the stabilizing effect of the centrifugal force. Preferably, all the blades of a given rotor are made of one piece of material.

The gear or screw compressor can advantageously be provided in the discharge port space with stable deflectors for directing the flow of gas exiting the rotating working spaces and the rotating discharge valves into the discharge port.

Preferably, these deflectors have a rotary design, are preferably connected to a compressor rotor, preferably they are connected to a rotating disk which carries the discharge valves. They direct the gas to flow in the opposite direction to the direction of rotation of the rotor. The gas flow rate in the deflectors is subtracted from the circumferential speed of the deflectors, and as a result, the deflectors slow down the rotation of the outgoing gas in the discharge port and thus act as the blades of a gas axial turbine. The rotating disk with discharge valves and reflectors thus forms a gas turbine. Thus, part of the kinetic energy of the emerging rotating gas is used to convert it into mechanical energy, preferably to drive a compressor, for example to cover losses from the gas flow in the discharge valves.

The gear or screw compressor can advantageously also be provided with deflectors in the space of the suction port in order to direct the flow of the suction gas from the space of the suction port in the direction of rotation.

-6GB 2019 - 732 A3 rotating working spaces and rotating suction openings in which suction valves can be located.

Preferably, these deflectors have a rotary design, preferably they are connected to the compressor rotor, preferably they are connected to a rotating disk with formed suction openings. The deflectors here have the opposite purpose than the turbine on the discharge side of the compressor - they pick up the gas supplied by the suction port, accelerate it and supply it, push it into the rotating suction openings. It therefore acts as a turbocharger blade. Energy is required to direct and accelerate the movement of the gas, but the overpressure of the gas at the outlet of the turbocharger can serve for faster, more intensive filling, overfilling of rotating compressor working spaces with intake gas and to cover gas flow losses in intake orifice valves.

The deflectors can generally be advantageously tiltable to ensure optimum flow in the event of a change in flow as the speed, flow rate or pressure conditions change. The deflectors preferably have an aerodynamic profile.

In compressor valves, it is necessary to take into account the aerodynamic and other losses that eg automatic valves cause depending on its shape, the strength of the closing springs and due to the inertia of the moving parts and the speed of the compressor. Forced actuation valves or control valves usually cause smaller losses in this respect, but at the cost of a complex and expensive mechanism to ensure their operation.

The design of the valve can be based on the conventional constructions known for high-speed compressors, but in the case of the compressor according to the invention, a considerably more confined space is available for the location of the discharge valve.

The invention also relates to a gear or screw compressor comprising a path for sucking gas into the working space and a path for expelling compressed gas from the working space, for carrying out the method according to the invention, the essence of which being comprising a path for supplying compressed gas leading directly to of the working space and is different from the path for expelling compressed gas from the working space.

The gear or screw compressor according to the invention preferably comprises an external separate pressure line through which compressed gas is supplied directly to the working space of the rotor.

The path for supplying compressed gas directly to the working space, preferably formed by a pressure port and a pressure line, preferably comprises a cooler and / or a regulator.

The compressors can be equipped with one pressure line, common to both rotors. However, it may be advantageous to use a separate pressure line for each rotor in order to fill the working spaces more accurately.

In a geared or screw compressor with two or three-tooth rotors according to the invention, the non-uniformity of gas flow, shocks and temperature of the extruded gas are reduced, but only partially, since an important feature of the invention, i.e. separation of supply and extrusion paths, cannot be easily and consistently applied compressed gas.

If the gas extrusion and compression paths open into the compressor body too close to each other, so that their separation is not carried out consistently, then the gas flow unevenness, shocks and temperature of the extruded gas are only partially reduced in this compressor. In the final stage of compression, the gas could also tend to flow in the opposite direction, ie out of the working space into the pressure line.

The relatively large spacing of the working spaces due to the small number of rotor teeth means that in the final phase of compression, the gas could tend to flow in the opposite direction, ie out of the working

-7 CZ 2019 - 732 A3 space into the pressure pipe.

The relatively small angular distance between the discharge port and the mouth of the compressed gas supply path to the working space in the case of two- or three-tooth rotors does not make it possible at all or not to control this supply of compressed gas at all or not well enough.

Advantageously, in such a case, at least gas backflow in the path for supplying compressed gas to the working space can be prevented by placing a non-return valve or non-return valve in this path, preferably as close as possible to the working space, to minimize the amount of gas whose movement is reversed in this path. however, at the cost of gas flow resistance losses.

A preferred embodiment of the invention can therefore be a gear or screw compressor in which the orifice of the nozzle for supplying compressed gas directly into the working space is circumferentially or angularly spaced at least one tooth pitch of the rotor from both the orifice orifice and the discharge orifice.

The opening of the pipe for supplying compressed gas directly to the working space is situated here in such a way that it cannot be connected by the space between the rotor teeth not only to the suction but also to the discharge opening, and thus to undesired loss of gas flow.

In this compressor, an external separate path can be formed for supplying compressed gas to the working space, different from the path for expelling compressed gas from the working space.

Even a compressor which has a correctly solved position of the pressure port preferably also comprises a non-return valve or non-return valve located in the pressure line as close as possible to the working space to prevent back pulsations of gas from the working space into the pipes, if these pulsations are not sufficiently limited by flow regulator.

Thus, a preferred embodiment of the invention is a screw compressor whose rotors have at least four teeth.

The invention also relates to a combination of the previous two embodiments, i.e. a gear or screw compressor, comprising a path for sucking gas into the working space and a path for expelling compressed gas from the working space, the essence of which being comprising a path for supplying compressed gas directly into the working space and is different from the path for expelling compressed gas from the working space, which is separated from the working space by at least one discharge valve.

Compressed gas in the compressor can thus be performed with cooled compressed gas from the discharge line and thus increase the value of the compressor overpressure limit given by the maximum allowable temperature and at the same time any external compression by preventing backflow of gas from the discharge line by means of discharge valves.

The compression cycle here consists of two parallel partial processes:

a) open process of intake (= discharged) gas:

- suction at suction pressure,

- polytropic compression with built-in compression ratio,

- compression by pressing with compressed gas with an increase in pressure to the final mixing value,

- polytropic compression under the discharge valve to the discharge pressure value,

- extrusion at the pressure extrusion value;

b) closed circulating gas process:

- 8 CZ 2019 - 732 A3

- compressed gas cooling,

- throttling by mixing with partially compressed gas to the final mixing value, - polytropic compression under the discharge valve to the discharge pressure value, - extrusion at the discharge pressure value.

Advantages of the invention:

- in compressors, unwanted external compression of the gas and its negative consequences, ie uneven gas flow, temperature of the discharged gas and noise, can be reduced,

- the built-in part of the compression ratio can be limited in compressors,

- compressors can adapt smoothly to almost any change in pressure conditions in the network while maintaining polytropic compression,

- the energy consumption of compressors can be reduced even with changes in pressure conditions in the network,

- individual compressors can be used for a wider range of operating gas pressures and thus their production range can be reduced.

Explanation of drawings

The invention will be further elucidated on the basis of exemplary embodiments according to the accompanying drawings:

Fig. 1 shows a diagram of a gear compressor with stable suction and discharge valves, Fig. 2 shows a diagram of a gear compressor with stable suction valves and rotary discharge valves, Fig. 3 shows a diagram of a screw compressor side with stable discharge valves, Fig. 4 shows a diagram of a screw compressor with stable and rotating valves, Fig. 5 shows a diagram of a screw compressor with pressure, Fig. 6 shows a diagram of a screw compressor assembly with pressure.

Examples of embodiments of the invention

Fig. 1 shows a diagram of a gear compressor with stable suction and discharge valves. In the compressor j, the working spaces 3 are delimited by the teeth of the rotors 2a, 2b and by the body 1 of the compressor. On the side of the left rotor 2a, three stable forced-acting suction valves 12a are axially arranged in the suction port 4, on the side of the right rotor 2b, four stable, forced-operated discharge valves 12b are also located in the discharge port 6. During one revolution of the rotors 2a, 2b, two compression cycles take place. The figure shows a situation where the suction valves 12a. where the suction of gas takes place, by rotating the rotors 2a, 2b it approaches the closed working space 3 between the teeth of the rotors 2a, 2b, containing partially compressed gas from the initial compression phase, when the discharge to the discharge valves 12b has not yet started.

From this it can be seen that during the compression cycle a relatively large amount of compressed gas is transferred from the discharge side of the working spaces to the suction side of the working spaces in the gear compressor and that the efficiency of the compression cycle can be increased by using the pressure energy of the transmitted compressed gas. The discharge valves 12b are forcibly operated with secondary control depending on the pressure in the discharge space, so that in the entire operating range of the compressor the compression is performed without supplying compressed gas from the discharge space back to the working space 3.

Fig. 2 shows a diagram of a gear compressor with stable suction valves and rotary ones

-9EN 2019 - 732 A3 discharge valves. The two automatic rotary discharge valves 14b are connected to the right rotor 2b so that they rotate together with it, so that the two interdental working spaces 3 are permanently assigned a separate rotary discharge valve 14b. The left rotor 2a is equipped with three automatic stable suction valves 13a. The figure shows a situation where compression or discharge of gas is currently taking place in the lower part of the compressor through the discharge valve 14b at the right rotor 2b (according to the pressure level in the discharge space), while at the top of the compressor

Fig. 3 shows a diagram of the side of a screw compressor with stable automatic discharge valves. The side 15 on the discharge side of the compressor is provided with 15 stable two-size circular discharge valves 13b and 2 uniform size rectangular discharge valves 13b. By gradually opening and closing the valves 13b during the rotation of the rotors 2a, 2b, pressure fluctuations in the interdental working spaces are minimized. The side panel 15 is only partially provided with discharge valves 13b in the lower half, therefore the basic part of the compression ratio in the compressor is fixed, and only further compression takes place with a compression ratio which depends on the instantaneous gas pressure in the discharge space.

Fig. 4 shows a diagram of a screw compressor with stable and rotary valves. In the sides 15a. 15b at the lower rotor 2b, rotating disks 16a are arranged on both the suction and discharge side. 16b, wherein automatic discharge valves 14b are seated in the rotary disk 16b on the discharge side. On the discharge side of the compressor, a turbine 17 is connected to the rotating disk 16b, which uses the kinetic energy of the compressed gas exiting the rotating discharge valves 14b and slows down the rotation, the swirling of the gas in the discharge port 6b. On the suction side of the compressor, a turbocharger 18 is connected to the rotary disk 16a, which directs the gas sucked from the suction port 4a and pushes it into the suction openings 5a in the rotary disk 16a and further into the working spaces. Automatic suction valves 13a are located in the side 15a on the suction side of the upper rotor 2a. In the case of negative pressure in the working spaces during the suction phase, they allow air to be sucked in from the suction nozzle 4. If the suction turbocharger 18 causes overpressure in the working spaces during suction,

A stable automatic valve 13b is located in the sidewall 15b at the upper rotor 2a on the discharge side. which opens into a common discharge port 6b. By optimizing the size and number of the discharge valves 13b, 14b at both rotors 2a, 2b, it is possible to further reduce the undesired leakage of compressed air from the discharge side of the working spaces to the suction side of the working spaces. The compressor can perform compression with a compression ratio that adapts automatically to the instantaneous gas pressure in the discharge space over virtually the entire operating pressure range.

Fig. 5 shows a diagram of a screw compressor with pressure. The opening of any pressure port 7a, 7b is more than one tooth pitch 19, 20 of the rotor 2a, 2b away from the discharge port 5b of the discharge port 6. Discharge valves are not located in the discharge openings 5b. The compressor performs basic compression with a built-in compression ratio and further increases the pressure to a value practically the same as in the discharge port 6 and can be performed in the discharge line by pressing with compressed gas supplied through the discharge port 7a, 7b from the discharge line after cooling in the cooler.

Fig. 6 is a schematic diagram of a pressurized air screw compressor assembly. By rotating the rotors 2a, 2b the air is sucked through the suction nozzle 4 into the working spaces 3, by further rotating the rotors 2a, 2b it is polytropically compressed to the basic pressure corresponding to the built-in compression ratio and transported to the pressure nozzles 7a, 7b. air from the pressure line 9a, 9b, where the air pressure is higher than the base pressure in the compressor. The resulting amount of air is conveyed in the working spaces 3 by further rotation of the rotors 2a, 2b via the automatic discharge valves 13b to the discharge port 6 and from there to the discharge line 8. Compressed air is transported for consumption in an amount corresponding to the sucked amount. From the discharge line 8, a pressure line 9a, 9b branches off

- 10GB 2019 - 732 A3 transfers the circulating part of the compressed air to the coolers 10a. 10b and further via control valves 11a. 11b to the pressure nozzles 7a, 7b and the working spaces 3 for compressing the intake air in further compression cycles. Since the discharge valves 13b are self-acting, the connection of the pressure port 7a, 7b and the discharge port 6 will be prevented in both rotors 2a, 2b, even if their circumferential or angular distance 5 is smaller than the tooth pitch of the rotors 2a, 2b.

Claims (20)

PATENT CLAIMS A method of performing a compression cycle in a gear or screw compressor, comprising sucking gas into the working space, a polytropic compression operation of the gas in the working space and an operation of expelling compressed gas from the working space into the discharge space, the gas being guided in certain operations. by compressing the gas in the working space polytropically with a compression ratio which varies throughout the compressor operating range according to the gas pressure in the discharge space, or is constant or adjustable in the first part of the compressor operating range and in the following part of the compressor operating range gas pressure in the discharge space. A method of performing a compression cycle according to claim 1, characterized in that a portion of compressing the gas in the working space is performed by supplying compressed gas directly to the working space in a different way than the way for expelling compressed gas from the working space into the discharge space. Method for carrying out a compression cycle according to one of Claims 2, characterized in that the compressed gas is cooled before being introduced into the working space and / or the flow of the compressed gas supplied to the working space is regulated. A method of carrying out a compression cycle according to any one of claims 1 to 3, characterized in that the heat obtained by cooling the compressed gas supplied to the working space is reused. Method for carrying out a compression cycle according to one of Claims 1 to 4, characterized in that the intake gas is directed and / or compressed before entering the working space. Method for carrying out a compression cycle according to one of Claims 1 to 5, characterized in that the kinetic energy of the compressed gas emerging from the working space into the discharge space is at least partially used for conversion into mechanical energy. A compressor comprising a path for sucking gas into the working space (3) and a path for expelling compressed gas from the working space (3), for carrying out the method according to any one of claims 1 to 6, characterized in that the gear or screw compressor comprises a path ( 8) for expelling compressed gas from the working space (3), which is separated from the working space (3) by at least one discharge valve (12b, 13b, 14b). Compressor comprising a path for sucking gas into the working space (3) and a path for expelling compressed gas from the working space (3), for carrying out the method according to any one of claims 1 to 6, characterized in that the gear compressor comprises a path (8) for expelling compressed gas from the working space (3), which is separated from the working space (3) by a control slide. Compressor according to Claim 7 or 8, characterized in that it comprises a path (9a, 9b) for supplying compressed gas, which leads directly to the working space (3) and is different from the path (8) for expelling compressed gas from the working space ( 3). Compressor according to one of Claims 7 to 9, characterized in that the path (9a, 9b) for supplying compressed gas which leads directly into the working space (3) and is different from the path (8) for expelling compressed gas from the working space (3), comprises a cooler (10a, 10b) and / or comprises a flow regulator (11a, 11b). - 12GB 2019 - 732 A3 Compressor according to one of Claims 7 to 10, characterized in that the path (10) for supplying compressed gas directly to the working space (5) comprises a non-return valve or a non-return valve. Compressor according to one of Claims 7 to 11, characterized in that the orifice (7a, 7b) for supplying compressed gas directly into the working space (3) is spaced from both the orifice (4) and the orifice (6). at least one tooth pitch of the rotor (2a, 2b). Compressor according to one of Claims 7 to 12, characterized in that the path (4) for sucking gas into the working space (3) is separated from the working space (3) by at least one suction valve (12a, 13a). Compressor according to one of Claims 7 to 13, characterized in that it comprises rotary suction valves and / or rotary discharge valves (14b) which are connected to the rotor (2a, 2b) so as to rotate together with it and for each the working space (3) is permanently assigned at least one separate discharge valve (14b) and / or at least one separate rotary suction valve. Compressor according to one of Claims 7 to 14, characterized in that it comprises deflectors for directing the flow of gas expelled from the rotating working spaces (3) into the discharge port (6b). Compressor according to one of Claims 7 to 15, characterized in that it comprises a gas turbine (17) for converting at least part of the kinetic energy of the gas expelled from the rotating working spaces (3) into mechanical energy. Compressor according to one of Claims 7 to 16, characterized in that it comprises deflectors for directing the flow of the suction gas from the suction nozzle (4a) into the rotating working spaces (3). Compressor according to one of Claims 7 to 17, characterized in that it comprises a turbocharger (18) for injecting the intake gas into the rotating working spaces (3). Compressor according to one of Claims 7 to 18, characterized in that the compressor valve is automatic. Compressor according to one of Claims 7 to 19, characterized in that the at least two discharge valves (12b, 13b, 14b) and / or the two suction valves (12a, 13a) are functionally independent of one another.