Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B25/00—Multi-stage pumps
  • F04B25/02—Multi-stage pumps of stepped piston type

Definitions

• the invention relates to a device for compressing gas, with a housing in which a separating element is arranged, along which a piston movable by means of a drive is guided and which passes through two dead center positions.
• Related devices are available in a variety of designs and designs on the market. A distinction is essentially made between two designs, namely motor-driven or hydraulically / pneumatically driven compressors.
• the known gas compressors which are also referred to as compressors, are large in size with a corresponding output and are complicated in construction, so that the manufacturing and maintenance costs are high due to the high assembly and maintenance costs involved.
• the object of the invention is to create a device for compressing gas, with which a high compression value can be achieved with little assembly and maintenance effort and which is functionally reliable in operation.
• a corresponding object is achieved by a device having the features of claim 1.
• these each have at least one inlet and one outlet valve, the respective inlet valve of a separation chamber following in series being connected via a connecting line to the outlet valve of the preceding separation chamber assigned to it.
• the inlet and outlet valves are preferably formed from non-return valves and are used in pairs for a compressor stage, it being possible to use so-called “Bernoulli valves”, as described in the applicant's German utility model G 94 08 660.5. It has been shown that these dynamically reversing check valves are almost insensitive to reactions from high-pressure lines, so that fail-safe operation of the compressor is ensured. With the "Bernoulli valves" mentioned, on the one hand the harmful spaces can be kept to a minimum and on the other hand no external devices for controlling the valves are required, for example in the form of a camshaft.
• the separating element for driving the piston has two separate feeds for fluid, each of which opens into a fluid chamber of variable volume at one end, which is sealed off by means of a seal separated from each other and which are delimited by the piston and the separating element.
• the stationary separating element which could also be regarded as the so-called “stator” of the device, therefore allows the fluid to be supplied directly via its interior, so that the movement of the piston which takes place along the outer circumference of the separating element, which is also called the “flying piston” be ⁇ "could not be hindered.
• Pressure oil is preferably used as the fluid; however, a pneumatic drive for special applications of the compressor could also take the place of the fluid drive with the same effect.
• the interior of the piston can be connected to the surroundings via a pressure relief duct, a relief space preferably kept at ambient pressure being delimited by the separating element, the piston and the housing. Because of this pressure relief towards the atmosphere, the oil and gas sides are reliably separated from one another in the device according to the invention. Possibly emerging Leakage oil can be returned directly to the tank, the gas pressure that is present increasing because of the pressure relief.
• the movable piston has an anti-rotation device which is provided with a pointer device which indicates the position of the piston and which, in order to switch over the direction of movement of the piston in its two dead center positions, interacts with a switching device with limit switches.
• a pointer device which indicates the position of the piston and which, in order to switch over the direction of movement of the piston in its two dead center positions, interacts with a switching device with limit switches.
• the piston area of the piston acting in the respective separation chamber is made smaller than the piston area in the previous pressure stage.
• the area ratios of the separation or pressure chambers mentioned also determine the maximum achievable final pressure of the compressor, with the selected graded area ratios simply stopping when a predeterminable maximum final pressure value is reached, so that an overload by pressure and Influence of temperature is avoided with certainty.
• At least some of the connecting lines are connected to these heat exchangers.
• the A coolant can be supplied inside the piston and / or into the relief chamber.
• the gas discharge can be infinitely predetermined by controlling the fluid quantities that can be fed into the fluid chambers, preferably by means of a pump and / or a throttle.
• the gas discharge from the compressor can therefore be regulated continuously, independently of the pressure conditions, by regulating the fluid delivery rate, setting on the predeterminable delivery rate of the pump being offered and, additionally or alternatively, setting on a controllable throttle.
• a further possibility is a demand-controlled extension of the switchover time at the two dead center positions of the piston, so that a high degree of efficiency can be guaranteed even with a low throughput.
• the device according to the invention is preferably used for an internal gas pressure system in which the gas quantities compressed to high pressure are stored in a memory from which the gas quantities necessary for an injection molding process for the mold can be called up. It has been shown that the device according to the invention can operate gas pressure systems more economically than with the compressors known hitherto. By retrieving the highly compressed gas quantities required for an injection molding process from the storage, smooth operation of injection molding machines of any kind is possible.
• FIG. 1 shows a longitudinal section through the compressor
• FIG. 2 shows a longitudinal section through the compressor shown offset by 90 ° with respect to the illustration in FIG. 1;
• FIG. 3 shows a view of the compressor corresponding to the representation in FIG. 1;
• FIG. 4 shows a view of the compressor corresponding to the illustration in FIG. 2;
• FIG. 5 shows a view of the compressor in the direction of arrow X in FIG. 1;
• FIG. 6 shows a view of the compressor in the direction of arrow Y in FIG. 1;
• Fig.12 different. Volume and pressure curves, as they prevail in the chambers I to V of the device;
• FIG. 13 shows a circuit diagram of a gas internal pressure system in which the compressor according to the invention is used.
• the device according to the invention shown in FIG. 1 has a housing, designated as a whole by 10, but consisting of several parts.
• a separating element 12 is provided in the lower half of the device and arranged inside the housing 10.
• a piston 14 is movably guided along the separating element 12 and moves through two dead center positions for a three-stage compression cycle, and with the housing 10 three separating chambers III connected in series for receiving the gas to be compressed, preferably in the form of nitrogen gas , IV and V, which form the compression chambers of the compressor.
• valves 16a, b, c For the series connection of the separation chambers III, IV and V, these have three inlet valves 16a, b, c and three outlet valves 18a, b, c.
• the valve pair 16a, 18a is part of the first suction or pressure stage, whereas the valve pair 16b, 18b is part of the second suction or pressure stage and the valve pair 16c, 18c are part of the third suction or pressure stage of the compressor.
• the respective inlet valve is
• a connecting line 20 which is only shown schematically in FIG. 1, connected to the outlet valve 18a or 18b of the preceding separating chamber III or IV assigned to it.
• a connecting line 20 which is only shown schematically in FIG. 1, connected to the outlet valve 18a or 18b of the preceding separating chamber III or IV assigned to it.
• inlet line 22 for low-pressure gas connected to the inlet valve 16a and an outlet line 24 which is connected to the outlet valve 18c, via which the gas which is highly compressed by the compressor is passed on for its further use.
• the separating element 12 For driving the piston 14, the separating element 12 has two separate feeds 26a, b for the fluid in the form of hydraulic oil, each of which ends at one end 28a, b in a fluid or oil chamber 1, 11 of variable volume, which separated from each other by means of a seal 30 and which are delimited by the piston 14 and the separating element 12.
• the Sealing 30 is formed by a separating bead arranged on the separating element 12, along the outer circumference of which a sealing ring runs in the usual and therefore not described in detail.
• a relief chamber VI arranged in the region of the underside of the compressor is delimited by the separating element 12, the piston 14 and the housing 10.
• This relief chamber VI is kept at ambient pressure by, as is shown in particular in FIG. 7, it is connected to the environment via three lateral recesses 32 which are laterally delimited by four longitudinal webs 34 of the housing 10.
• shell-like housing segments 36 are placed over the recesses 32 and are firmly connected to the longitudinal webs 34, the cover produced in this way is not pressure-tight, with the result that the ambient pressure in the relief chamber VI is established.
• a further relief chamber VII is formed by the interior of the piston 14, which is connected to the environment via a pressure relief channel 38, so that the ambient pressure also arises in the relief chamber VII.
• the pressure relief channel 38 mentioned can also be divided into two channel sections 38a, b at its end pointing towards the environment.
• the movable piston 14 has an anti-rotation device, designated 40, which is provided with a pointer device 42 which indicates the position of the piston 14 and which switches over the direction of movement of the piston 14 in its two dead center positions with a switching device (not shown) cooperates with two end position switches 44 opposite each other in the direction of travel of the piston 14.
• a pointer device 42 which indicates the position of the piston 14 and which switches over the direction of movement of the piston 14 in its two dead center positions with a switching device (not shown) cooperates with two end position switches 44 opposite each other in the direction of travel of the piston 14.
• the individual chambers I to VII of the compressor are each separated from one another by customary and therefore not described sliding seals.
• the piston 14 is jammed or to avoid tipping, as the only part of the device which is moved with a larger travel path, is guided by guide belts 46 at two widely spaced locations.
• a guide is provided for the piston 14 between the chambers III and IV directly against the housing 10, whereas the second guide of the piston 14 takes place along the cylindrical outer circumference of the separating element 12.
• a further third or center guide is provided between the seal 30 of the separating element 12 and the inner circumference of the piston 14 forming the spaces I and II.
• a head part 52 is present as a further housing part, onto which the receptacles 54 with the check valves 16c and 18c are placed.
• the receptacles 54 for the check valves are standardized components and, as shown in particular in FIG. 3, are used for all check valves 16, 18.
• the head part 52 has a central bore 56, into which the piston 14 engages with a cylindrical extension 58, which in turn is penetrated by a centrally arranged blind bore 60.
• the length of the extension 58 is dimensioned such that the extension 58 still engages in the cylinder or central bore 56 even in the lowest travel position of the piston 14.
• the first effective piston surface 62 is formed by the end face of the piston 14 shown at the top in FIG. 1, which faces laterally from the outer circumference of the piston 14 in the region of the guide bands 46 and the outer circumference of the cylindrical extension 58 is limited.
• the second effective piston surface 64 is arranged in the piston 14 like a shoulder below the upper guide band 46 and is delimited radially by the outer circumference of the piston 14 and the inner circumference of the housing 10 in the region of the chamber IV.
• the third piston surface 66 is formed by the tip of the extension 58 and is delimited radially from the outer circumference of the extension 58.
• the piston surface 62, 64, 66 of the piston 14, which acts on the compression as the pressure increases in the respective separating chamber III, IV, V, is designed to be smaller than the piston surface in the previous pressure stage.
• the first piston surface 62 is thus larger than the second 64 and this in turn larger than the third piston surface 66.
• the part of the housing 10 which delimits the separation chambers III and IV and which has a pair of receptacles 54 with valves 16a, 18a and 16b, 18b at the end is sealed at the end with appropriate seals from the environment, which, as already described, is carried out is not the case for the housing part with the lateral recesses 32 shown at the bottom in FIG.
• a coolant (not shown) can be fed into the interior VII of the piston 14 and possibly into the further relief space VI.
• the oil and gas sides of the compressor are safely separated by the described pressure-relieved rooms VI and VII.
• the chamber VII achieves a minimally moving mass of the piston 14, which avoids the otherwise usual problems caused by the large inertial forces of the moving masses in known compressors.
• the cooling medium can act directly on the inside of the piston 14, which is particularly thermally stressed.
• the compression ratios, the dead spaces and the efficiencies of the individual stages are designed accordingly.
• a transparent cap 68 to be placed on the pointer device 42 which is moved during the operation of the compressor and which is firmly connected to the outer circumference of the housing 10.
• the fluid chambers II and I are alternately filled or emptied with hydraulic oil, so that the piston 14 is moved back and forth in the axial direction.
• the pointer device of the anti-rotation device 40 alternately comes into proximity or comes into contact with the upper and lower limit switch 44 in the two dead center positions of the cylinder 14, which then switches as part of the switchover device (not shown) the reversing process of the hydraulic supply or removal Control from the fluid chambers 1.11.
• the pointer device 42 consists of two collar-like neck parts which are clamped onto the outer circumference of the piston 14 by means of a screw connection and a dovetail lock.
• the piston is guided by the pointer device 42, which is guided through two PTFE disks in one of the four longitudinal openings 32. This reliably prevents radial movement of the piston.
• a heat exchanger 72 which serves as a cooling device and which extracts the heat of the gas occurring during the compression process, can be connected to the connecting lines 20 in each case.
• the heat exchanger used for this purpose according to FIGS. 8 and 9 has connection points 74a, b which are connected to the respective connecting line 20 and which are used for introducing and discharging the gas into and out of the heat exchanger 72 .
• the gas is passed through a coil 76 within the heat exchanger 72 and cooled in countercurrent by means of water which passes into and out of the heat exchanger 72 via the connections 78.
• Such heat exchangers are sufficiently known to the specialist world, so that this will not be dealt with in any more detail.
• connection line 20 again made available to the compressor.
• measuring connections 79 are provided (FIG. 2), into which pressure indicators can be used to monitor the device. Such measurement indicators can also be used at other points in the device, if necessary.
• FIG. 12 the volume and pressure ratios for the chambers I to V are shown, the ratios on the one in FIG 12, the left half of the picture between the two vertical dash lines relates to the switching process of the piston 14 from its lower dead center position shown in FIG. 11 to the upper dead center position according to FIG. 10 and to the right of this in FIG arranged curve courses up to the next vertical dash line course relate to the switching process from a representation according to FIG. 10 to FIG. 11.
• both the volume and the pressure in the fluid chamber II decrease to zero and the fluid in the chamber II is discharged via the feed line 26a. Furthermore, the gas located in the medium pressure chamber IV is brought into the high pressure chamber V via the outlet valve 18b and the inlet valve 16c. This results in chamber IV in the compression process shown on the left in FIG. 12 and in chamber V the gas is sucked in.
• the piston 14 moves again from its position shown in FIG. 10 to its former top dead center position as shown in FIG. 11. This movement is achieved in that fluid is pumped into the chamber II via the feed line 26a, whereas the chamber I is kept pressureless via the feed line 26b.
• the gas in the chamber III is compressed, which is pressed into the medium-pressure chamber IV via the outlet valve 18a, the connecting line 20 and the inlet valve 16b. So there is a suction process in chamber IV as shown in the right half of FIG. 12. Furthermore, there is a compression process in high pressure chamber V, so that in the second phase after switching, the compressed to the desired final pressure Gas quantity is discharged from the compressor via the outlet valve 18c and the line 24. The gas discharged can then be highly compressed to 400 bar. In addition to nitrogen gas, the compressor is also suitable for the compression of air. At the end of the three-stage compression and suction process, a new cycle begins as just described, ie the piston 14 moves again from its position shown in FIG. 11 into a position according to FIG.
• the use of the device according to FIGS. 1 to 12 for an internal gas pressure system is shown below with reference to FIG. 13, the internal gas pressure system known per se being described only to the extent that it is necessary to explain the invention.
• the gas discharge from the compressor is infinitely variable via a control of the fluid quantities that can be fed into the fluid chambers I, II.
• a continuously adjustable hydraulic pump 80 and / or an adjustable throttle 82 can be used.
• the final pressure on the gas side of the compressor depends only on the inlet pressure and the ratio of the compressor chambers III to V, the final pressure being determined with the aid of
• the switching of the fluid chambers I to II is carried out via a 4/3-way valve 84, which is controlled accordingly via the limit switches 44 of the switching device (not shown).
• the gas quantities compressed to high pressure are delivered to a reservoir 88, for example in the form of a hydraulic reservoir, via the connecting line 24, which is secured by a check valve 86 of a known type.
• the gas is stored there and the gas quantities necessary for an injection molding process for the mold 90 can then be called up.
• a continuous gas introduction into an injection mold can be carried out via a hydraulic Reach storage 88, the compressor being supplied with gas for charging chamber III via supply line 22 from nitrogen storage containers 92. Since the compressor according to the invention has a small structure and can also be produced inexpensively, it can be used in a particularly advantageous manner for gas pressure systems of any kind.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Compressor (AREA)
• Engine Equipment That Uses Special Cycles (AREA)
• Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
• Lubricants (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

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ID=6495783

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Cited By (1)

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Citations (5)

Family Cites Families (9)

• 1993
  • 1993-08-23 DE DE4328264A patent/DE4328264A1/de not_active Withdrawn
  • 1993-10-13 TW TW082108448A patent/TW247344B/zh active
• 1994
  • 1994-07-02 CA CA002165063A patent/CA2165063A1/en not_active Abandoned
  • 1994-07-02 WO PCT/EP1994/002174 patent/WO1995006204A1/de not_active Ceased
  • 1994-07-02 JP JP7507286A patent/JPH09502237A/ja active Pending
  • 1994-07-02 DE DE59404288T patent/DE59404288D1/de not_active Expired - Fee Related
  • 1994-07-02 AU AU74572/94A patent/AU7457294A/en not_active Abandoned
  • 1994-07-02 ES ES94924224T patent/ES2107855T3/es not_active Expired - Lifetime
  • 1994-07-02 EP EP94924224A patent/EP0715689B1/de not_active Expired - Lifetime
  • 1994-07-02 AT AT94924224T patent/ATE159080T1/de active
  • 1994-07-02 US US08/549,734 patent/US5782612A/en not_active Expired - Fee Related
  • 1994-07-29 MY MYPI94001975A patent/MY111012A/en unknown
  • 1994-08-23 ZA ZA946396A patent/ZA946396B/xx unknown
• 1996
  • 1996-02-16 KR KR1019960700916A patent/KR960704156A/ko not_active Abandoned
• 1997
  • 1997-10-29 GR GR970402828T patent/GR3025193T3/el unknown

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