DE4021715C1 - Gas pressure regulator for injection moulding machine - has electrohydraulically controllable proportional valve in transfer line between pressure raising device and mould - Google Patents

Abstract

A regulating arrangement for gas pressure in a process for the prodn. of plastic components in injection moulding machines, includes a device for raising the source pressure of the gas to the working pressure. A transfer line is located between the pressure raising device and the mould, which contains an electro-hydraulically controllable proportional valve. A recovery compressor is connected to the valve unit. ADVANTAGE - The arrangement enables the pressure to be controlled precisely.

Description

The invention relates to a control device for the gas pressure in the internal gas pressure process for the production of Plastic parts on injection molding machines according to the characteristics in the preamble of claim 1.  

Through the "GIP" brochure from Mannesmann-Demag Kunst stofftechnik, Altdorfer Straße 15, 8501 Schwaig 1 in the Edition 0789 15T 18 318 665 it is known to be initially an art inject the fabric cushion into the injection mold and then a defined amount of gas, especially nitrogen, over a Inject sprue system. The gas in the mass cushion is displaced then the melt to the mold wall, so that in the molding Cavity is formed.

The gas is provided in interchangeable bottles poses. To achieve the required working pressure, the gas is transferred from the respective exchange bottle into one pressure translator acting as a media separator leads. The pressure intensifier has two interconnected their pistons. The larger piston is on both sides hydraulically loadable. This is between a moto rically driven hydraulic pump and the pressure intensifier a suitable changeover valve is provided. The one in the plane smaller pistons act on the assigned piston chamber inflow of gas from the exchange bottle and increased when the hydraulic piston moves, the pressure of the gas increases the necessary level of work.

It is also stated in the prospectus that Gas can be recovered from the molding. Like this is not described.

A shortcoming of the known measure is that so probably the quantity as well as the achievable working pressure of the Gases directly dependent on the displacement of the pressure intensifier are. Therefore, the gas cannot be prevented from widening uncontrolled on the plastic in the injection mold meets. This has the consequence that in particular in the case of Shaping complicated plastic moldings  not in the desired way in all areas of the spray shape with uniform thickness or with the required Liche thickness is pressed against the walls of the injection mold. Also the plastic melt can break through.

Another disadvantage is seen in the known case that both the increase in gas pressure and the dosage the amount of gas is carried out by a common component. The is for a system with several injection molding machines a separate gas unit for each of the injection molding machines to provide.

Finally, it is a disadvantage that the recovery that is in the molding and under pressure Gas only up to the level of the pre-filling pressure of the pressure is possible.

To the extent of DE-GM's 89 11 222 is proposed by means of of a stage piston accumulator gas in a predetermined manner to feed an injection mold. It is essential for this that the stepped piston regardless of the peculiarities of the individual case in a precisely defined starting position are located. In this starting position, the gas space is in front nachge the smaller piston by one of the pressure source switched single-piston accumulators via a check valve filled with a monitored pressure. Because the forward movement the stepped piston always from the same starting position runs out, the supply of gas to the injection mold in repro doable way.

The recovery of the gas cleaned by a filter takes place firstly in that gas directly into the gas space of the stage piston accumulator is returned by the Step piston are withdrawn, then in that at reduced pressure a switching valve between the step Piston accumulator and the injection mold closed and a switch  valve between the injection mold and the single piston accumulator is opened so that this is also refilled. Just Residual gas with low pressure is fed into the gas valve Free derived.

The invention is based on that in the preamble of Claim 1 control device described the problem based on improving them so that an exact Druckge regulated dosing of the gas when entering the spray ling as well as a large utilization rate of the provided Gases with a high recovery share is possible.

According to the invention, this problem is solved in the features listed in the characterizing part of claim 1.  

An essential aspect of the invention is that the three basic functions of increasing gas pressure, Injek tion of the gas and gas recovery by separate radio tion modules are realizable. This can be an optimal Adaptation to the respective operating conditions guaranteed will. This is especially so due to the clear separation the device for increasing the source pressure of the gas the working pressure from gas injection possible, each amount of gas stored under high pressure for a small Mold volume or at low pressure for a corresponding Use a larger mold volume or if several are used Proportional valves several injection molding machines in parallel to be able to use.

Another significant advantage of the invention is therein seen that the gas under pressure - in particular nitrogen - with the help of the continuously adjustable Proportional valve clearly regulated from zero pressure injected into the injection mold up to the maximum pressure and demented speaking of the injection mold can be removed again. The complete functional sequence including the Control of the gas pressure in the tip form programmed ben. The pressure build-up and gas recovery takes place via the control electronics, while the regulated mold pressure through the higher-level CNC control of the injection molding machine featured will give.

As a result, any desired configuration can now be Spritzlings with a clearly defined wall thickness without the Risk of gas breakthroughs.

The proportional valve can be used as a 2/2-way proportional valve til (proportional throttle) or as a 3/3-way proportional valve be formed.  

With the help of the part of the device for gas recovery recovery compressor and that on below Different gas pressures can be set after gas storage not only the gas contained in the molding energy-saving and fractionally recovered who that, but it's also a very high recovery rate except for a small and therefore negligible rest quantity achievable.

A particularly advantageous development of the invention basic principle is in the features of the patent Proof 2 included. Because the back of the pressure sensor The actual pressure value can be reported using the Control electronics through an electrical input signal Gas flow continuously through the proportional valve represents and any pressure rise and fall curves will be realized.

An appropriate design of the proportional valve be write the features of claim 3. About the elek The control piston can consequently be actuated trically ben so hydraulically acted that the conical Sealing body can be moved extremely sensitively relative to the sealing seat is. The cross section of the gas stage is approximate formed proportional to the stroke of the sealing body. The mo The mental position of the control piston is in each case via the Position sensor reported to the control electronics. For the tax valve can include an amplifier card that connects the An control of the control valve and the position control of the actu piston included. This amplifier card can be used to the position of the gas stage is given a zero adjustment will. If in the higher-level machine control Pressure regulator is integrated, from this the Propor tional valve can be controlled as an actuator.  

Furthermore, it is possible according to the invention, the amplifier card with a plug-in daughter card for the function to expand the pressure control. This then includes one Pressure regulator with PI behavior and activation of the differen decorated actual pressure value. The position control of the control piston remains as an independent or subordinate regulation The circuit should be designed so that the smaller input signal is switched through. The means that if the pressure is significantly below the setpoint, the Opening of the gas level is determined by the position setpoint and when approaching the pressure setpoint the pressure regulator The opening of the gas stage is reduced until it is reached Setpoint becomes zero. For practical use means this means that to operate the pressure control, the position setpoint for example +10 V or any value between 0 and 10 V is set when a maximum valve opening is to be limited. This applies e.g. B. for very small Mold volumes or the rate of increase in pressure to limit. The pressure regulator then leaves the gas level like this wide open that as an electrical value or as a pressure predetermined setpoint is reached.

The features of claim 4 allow the rule to process the relevant parts of the gas stage extremely precisely, easy to maintain and easy to replace when worn.

The metallic sealing element according to the features in Claim 5 allows, on the one hand, the gas at pressures up to about 500 bar against the atmosphere and on the other hand to be able to absorb the hydraulic pressure. This design is used with a 3/3-way proportional valve, at which depends on the position of the length on the sealing body side section of the control rod and thus also the sealing body the area connected to the pointed shape in front of the sealing seat  either with the one behind the sealing seat, with the on direction connected to increase the source pressure of the gas Area or connected to the gas recovery facility that is. In this context, the regulated increase the pressure in the injection mold the connection between the Device for increasing the source pressure of the gas and Injection mold opened while the connection between the Injection mold and the device for gas recovery locked is. The flow rate depends on the position of the control rod. With controlled lowering of the pressure however, the sealing body is pressed fully onto the sealing seat and the connection between the injection mold and the device device for gas recovery opened. At constant pressure the injection mold both to increase the device the source pressure as well as towards the facility for Gas recovery blocked.

The object of the features of claim 6 is the Z. B. from commercially available interchangeable bottles (rental bottles) withdrawn gas from the delivery pressure 200 bar or that a liquid gas evaporator system with a gas pressure of about 10-15 bar gas originating on the required work pressure of about 500 bar and increase for work to provide process required amount of gas.

The gas filter downstream of the high-pressure accumulator according to Claim 7 is used for cleaning and possibly cleaning of the gas.

In claim 8 is an advantageous embodiment the pre-compression according to the invention into the molding described for gas to be transferred. The pre-compression includes a pre-compressor and a pre-pressure accumulator. Here the gas is at the required inlet pressure of the High pressure compressor increased by about 150 bar. Includes e.g. B. the gas source can have at least two interchangeable bottles  this way an empty exchange bottle always against one new full exchange bottle can be exchanged without the spraying process must be interrupted. Will be a full one Exchange bottle to the facility to increase the swelling pressure connected, the gas flows from the change bottle via the check valve to the pressure equalization in the Form memory. By means of the pre-compressor compressor each replacement bottle up to a residual pressure of about 50 be emptied in bar.

The switching valve according to claim 9 allows it, without major interruption, easily from one to switch to the other exchange bottle. It is advantageous if between each exchange bottle and the Changeover valve is incorporated into a blocking element. The order switching valve can be electric, pneumatic, hydraulic or be manually operable.

In claim 10, an embodiment is characterized net, which uses a 3/3-way proportional valve.

The device for gas return explained in claim 11 extraction is via a switching valve to the transfer line between a 2/2-way proportional valve and the Injection mold connected. Only then will the switching valve opened via the control electronics when gas comes out of the spray ling should be removed. The gas filter ensures that that contaminated gas is cleaned in the molding, before it goes into the component of the gas return facility gas storage.

The features of claim 12 allow a frak tioned gas recovery in three pressure levels. This can achieved a high material and energy recovery rate will.  

In the first stage, part of the in the injection mold contained gas with the working pressure of about 500 bar by opening the switching valve into the pre-pressure accumulator leads. After the pressure in the injection mold drops to approx. The spoke assigned to the medium pressure accumulator opens at 180 bar cherventil, so that another part of the gas now in the medium pressure accumulator can flow. Then is the pressure in the injection mold dropped to approx. 60 bar, that opens up the Storage valve assigned to low pressure accumulator. The gas now flows into the low pressure accumulator until the pressure in the injection mold has dropped to approx. 10 to 12 bar. The ver residual gas pressure in the injection mold can over the off release valve into the atmosphere.

Z. B. a 2/2-way proportional valve is used, so the features of claim 13 are advantageous. In this case there is no direct connection between the Propor tional valve with the device for gas recovery. The gas from the molding is passed through the throttle valve Gas recovery device supplied. With regulated Increasing the pressure (increasing pressure curve) is the throttle valve closed, and there is pressure control via the proportional valve and the pressure transducer between the Injection mold and the control electronics. With controlled lowering of the pressure (falling pressure curve) becomes the throttle valve opened and set to constant flow. The pressure regulation then also takes place via the 2/2-way proportional valve.

The emptying of the low pressure accumulator, the medium pressure memory and if necessary. the characteristics of the interchangeable bottles serve of claim 14. So on the one hand to about 50 bar using the pre-compressor emptied replaceable bottles through the recovery compressor  be emptied to a residual pressure of approx. 10 bar. The low-pressure accumulator is emptied via the Recovery compressor in the medium pressure accumulator. With With the help of the pre-compressor, the content of the Mit pressure accumulator promoted in the form accumulator. The Emptying the interchangeable bottles and the low pressure accumulator takes place mutually. Thereby the recovery circle a priority circuit can be assigned so that a maxima recovery rate is ensured. With the fiction according to the arrangement is a theoretical recovery rate reachable by 95% and the recovered gas energiespa back into the gas at the highest possible pressure level injection system feedable.

With the help of the features of claim 15 is a direct ter connection of a gas source consisting of interchangeable cylinders to the gas line of the gas recovery facility Lich.

The features of claim 16 form Sicherheitsele elements against a gas pressure kickback. With a liquid gas Evaporator system as a gas source eliminates the direct connection gas pipeline.

Using the features of claim 17, the Pressure and flow rate gradation can be freely chosen so that they both compress the gas to the working pressure as well also a high gas recovery rate with the lowest possible Residual gas pressure in the injection mold and an almost complete one Safe emptying of the gas source in an economical manner poses. The performance of all compressors can be easily by changing the piston speed or adjust the number of strokes as required. The reversal of the Compressors are made electrically by solenoid valves. The  Solenoid valves are attached directly to the compressors. The compressors thus form a fully functional one Unit.

The invention is based on in the drawings illustrated embodiments explained in more detail. It demonstrate:

Fig. 1 is a schematic diagram of a Regelvor direction for gas pressure in the gas pressure process for the production of plastic parts on injection molding machines;

Fig. 2 is a circuit diagram of a modified embodiment of the control device of Fig. 1;

Fig. 3 is a circuit diagram showing in part another embodiment of a control device;

Fig. 4 in an enlarged view in vertical longitudinal section a portion of a component of the control device of Fig. 2 or 3 forming 2/2-way proportional valve and

Fig. 5 in an enlarged view in the vertical longitudinal section of a component of the control device of FIG. 1 or 3 forming 3/3-way proportional valve.

The control apparatus shown in FIG. 1 1 for the gas pressure in the gas internal pressure process for the production of plastic parts in injection molding machines comprising a device 2 for increasing the filling pressure of the, 4 nitrogen contained in the working pressure, means 5 for transferring bottles provided exchange 3 of the under Working pressure of nitrogen in an injection mold 6 forming part of the injection molding machine (not shown in detail) and a device 7 for recovering the nitrogen from the injection mold 6 .

The device 2 for increasing the filling pressure of the nitrogen contained in the exchangeable bottles 3 , 4 has a high-pressure compressor 8 and a high-pressure accumulator 9 . With the help of the high-pressure compressor 8 , the nitrogen removed from the commercially available interchangeable bottles 3 , 4 is increased from the filling pressure (delivery pressure) from approximately 200 bar to the required operating pressure of 500 bar.

In order to achieve the inlet pressure of the high-pressure compressor 8 of approximately 150 bar, a pre-compressor compressor 10 and a pre-pressure accumulator 11 are also provided. The admission pressure reservoir 11 with a maximum pressure of 200 bar is connected via a line 12 to the high pressure compressor 8 . The pre-compressor 10 is connected to this line 12 via a branch line 13 .

The two interchangeable bottles 3 , 4 are connected to a switching valve 15 which is electrically adjustable against the return force of a spring 14 . In the lines 16 , 17 between the interchangeable bottles 3 , 4 and the switching valve 15 blocking elements 18 , 19 are incorporated, with which the interchangeable bottles 3 , 4 can be connected to the lines 16 , 17 or separated from them.

In a line 20 between the switching valve 15 and the line 12 between the pre-pressure accumulator 11 and the high pressure compressor 8 is a in the direction of the Wechsella's 3 , 4 blocking check valve 21 incorporated.

In a transfer line 22 between the device 2 for increasing the filling pressure of the nitrogen to the working pressure and the injection mold 6 , the device 5 for the controlled injection of nitrogen into the injection mold 6 is divided. In addition, a gas filter 23 is provided in the transfer line 22 between the high-pressure accumulator 9 and the device 5 .

The device 5 comprises a 3/3-way proportional valve 24 (see also FIG. 5) with a gas stage 25 with a spring-loaded conical sealing body 26 and an adapted sealing seat 27 , an electrically actuable control valve 28 , a hydraulic stage 29 with a via the control valve 28 against the restoring force of a spring 30 hydraulically actuated actuating piston 31 and with an actuating rod 32 which can act on the sealing body 26 and a displacement sensor 35 connected to the actuating piston 31 and coupled to a control electronics 33 via a line 34 . The control electronics are connected to a machine control 76 of the injection molding machine.

The sealing body 26 , the sealing seat 27 and the sealing body-side longitudinal section 36 of the actuating rod 32 are provided in an exchangeable valve cartridge 37 ( FIG. 5).

The sealing body-side length section 36 of the actuating rod 32 is provided with a metallic sealing element 38 to interrupt the connection 41 between a working connection 39 of the gas stage 25 and a storage connection 40 connected via a line 80 to the device 7 for gas recovery to be explained in more detail below. With 78 a pressure connection is designated, the verbun via the transfer line 22 with the device 2 for increasing the filling pressure.

As can also be seen in FIG. 1, the control connection 42 of the control valve 28 , which can be displaced against the restoring force of a spring 43 , is connected to the control electronics 33 via a line 44 . In addition, the switching connections of the control valve 28 are connected to a hydraulic pressure source 45 and a hydraulic tank 46 .

The nitrogen is introduced into the injection mold 6 in a pressure-controlled manner via the 3/3-way proportional valve 24 . The injection quantity, the injection time and the internal pressure of the injection mold 6 are specified via the programmable control electronics 33 . The feedback of the actual pressure value takes place via an electronic pressure transducer 47 , which is connected to the transfer line 22 between the proportional valve 24 and the injection mold 6 in the immediate vicinity of the injection mold 6 and can be coupled to the control electronics 33 via a line 48 . The regulated mold pressure is predetermined by the CNC control 76 of the injection molding machine.

In the standby position of the 3/3-way proportional valve 24 , the connection 41 between the working connection 39 and the storage connection 40 is opened (illustration according to FIG. 5). If the actuating piston 31 moves in the direction of the gas stage 25 , the connection 41 between the working connection 39 and the storage connection 40 is first interrupted by the sealing element 38 . If this connection 41 is then closed, the actuating rod 32 rests on the sealing body 26 and displaces it relative to the sealing seat 27 with further stroke movement of the actuating piston 31 , so that the device 2 for increasing the filling pressure via the line 22 , the pressure connection 78 the gas stage 25 and the working connection 39 is connected to the injection mold 6 . By specifying the control electronics 33 , all desired coverage ratios and pressure amplifications can be set. For gas cleaning, a gas filter 51 can be provided in line 22 between the 3/3-way proportional valve 24 and the injection mold 6 .

The device 7 for recovering the nitrogen from the injection mold 6 is connected to the storage connection 40 via a switching valve 50 , which is electrically adjustable against the restoring force of a spring 49, and the line 80 . The device 7 has a gas line 52 , to which between the switching valve 50 and the pre-compressor 10 with a medium pressure accumulator 53 and a low pressure accumulator 54, each against the restoring force of springs 55 , 56 electrically adjustable storage valves 57 , 58 and a gas line 52 the atmosphere A connecting exhaust valve 59 are closed. The outlet valve 59 is electrically adjustable against the return force of a spring 60 .

Between the connections 61 of the low-pressure accumulator 54 and 62 of the medium-pressure accumulator 53 to the gas line 52 on the one hand and the connections 62 of the medium-pressure accumulator 53 and 63 of the interchangeable bottles 3 , 4 to the gas line 52 on the other hand, there is in each case a check valve 64 blocking the switching valve 50 , 65 provided. Furthermore, a check valve 75 is incorporated into the return line 69 between the low pressure accumulator 54 and the accumulator valve 58 .

Furthermore, Fig. 1 reveals that in the line 66 between the changeover valve 15 for the interchangeable bottles 3 , 4 and the gas line 52, an electrically adjustable against the restoring force of a spring 67 source valve 68 is connectable bar.

The interchangeable bottles 3 , 4 on the one hand and a return device 69 between the low-pressure accumulator 54 and the associated storage valve 58 on the other hand are via an electrically adjustable against the restoring force of a spring 70 to switch valve 71 and a recovery compressor 72 to a return line 73 between the medium pressure accumulator 53 and the this associated storage valve 57 alternately connectable.

The electrical control connections of all valves 15 , 50 , 57-59 , 68 and 71 , like the compressors 8 , 10 and 72, are connected to the control electronics 33 via lines (not shown).

The nitrogen is recovered in three pressure stages. In the first stage, the nitrogen contained in the injection mold 6 is released at a pressure of approximately 500 bar by opening the connection 41 , closing the sealing seat 27 and opening the switching valve 50 via the line 80 and the gas line 52 into the pre-pressure accumulator 11 . After the internal pressure of the injection mold 6 has dropped to approximately 180 bar, the storage valve 57 assigned to the medium pressure accumulator 53 opens, and the nitrogen flows into the medium pressure accumulator 53 . If the internal pressure of the injection mold 6 then drops to approx. 60 bar, the storage valve 58 assigned to the low pressure accumulator 54 opens and the nitrogen flows into the low pressure accumulator 54 until the internal pressure of the injection mold 6 has dropped to approx. 10 to 12 bar. The remaining form residual pressure of about 10 to 12 bar can then be released into the atmosphere A via the outlet valve 59 .

The low-pressure accumulator 54 is emptied into the medium-pressure accumulator 53 with the aid of the recovery compressor 72 . With the pre-compressor 10 , the content of the medium pressure accumulator 53 is conveyed into the pre-pressure accumulator 11 .

If a full nitrogen exchange bottle 3 , 4 is connected, the nitrogen flows through the check valve 21 until the pressure equalization from the connected exchange bottle 3 or 4 into the pre-pressure accumulator 11 . In addition, the precompressor compressor 10 allows the exchangeable bottles 3 , 4 and the medium pressure accumulator 53 to be emptied to a residual pressure of approximately 50 bar.

The largely complete emptying of the interchangeable bottles 3 , 4 takes place by a corresponding shift of the changeover valves 15 and 71 , the interchangeable bottles 3 , 4 first being emptied to about 50 bar by the pre-compressor compressor 10 , then switched to the recovery compressor 72 and by this to one Residual pressure of approx. 10 bar.

The emptying of the interchangeable bottles 3 , 4 and the low-pressure accumulator 54 takes place alternately.

With the aid of the control device 1 described above, it is possible, depending on the parameters specified by the desired configuration and / or the wall thickness of the respective injection molded part, to set both the pressure of the nitrogen to be injected into the injection mold 6 from zero or any predetermined initial value to increase continuously or step by step up to the final pressure and also to reduce the pressure of the nitrogen removed from the injection mold 6 continuously or gradually from the final pressure to the value zero or any value which can be predetermined.

Fig. 2 shows a control device 1 ', which in contrast to the control device 1 of Figs. 1 and 5 has a 2/2-way proportional valve 24 ' (see also Fig. 4). This 2/2-way proportional valve 24 'is with the area in front of the sealing seat 27 via the working connection 39 ' and via the line 22 to the injection mold 6 and with the area towards the sealing seat 27 via the pressure connection 78 'to the one direction 2 connected to increase the filling pressure. Furthermore, the control device 1 'comprises an electrically switchable throttle valve 74 , which is divided into a line 77 , which is connected on the one hand between the switching valve 50 and a gas filter 81 to the return line 69 and on the other hand behind the check valve 64 to the gas line 52 . The gas line 52 is connected via the return line 69 to the line 22 between the 2/2-way proportional valve 24 'and the injection mold 6 . All other components correspond to the training of the control device 1 .

If the pressure rises, the throttle valve 74 is closed. The pressure control takes place via the 2/2-way proportional valve 24 'and the pressure sensor 47 .

However, if the pressure drops, the throttle valve 74 is open. It is set to constant flow. The pressure control is carried out via the 2/2-way proportional valve 24 '. With a falling pressure curve, the flow rate of the 2/2-way proportional valve 24 'is smaller than that of the throttle valve 74 , while with increasing pressure curve, the flow rate of the 2/2-way proportional valve 24 ' is larger than that of the throttle valve 74 . At constant pressure, the flow rate is the same.

In Fig. 3, a control device 1 '' is illustrated with a gas source 79 , which consists of a liquid gas evaporator system with a gas pressure of about 10-15 bar. This gas source 79 can be closed directly via the changeover valve 71 and the recovery compressor 72 to the return line 73 . All other components of the control device 1 '' can be of the regulating device 1 or, normally those apparatus 1 ', respectively.

Claims (17)

1. Control device for the gas pressure in the gas pressure process for the production of plastic parts on injection molding machines, which devices ( 2 , 5 , 7 ) to increase the source pressure of the gas provided on the working pressure, for the targeted transfer of the gas under working pressure into the injection mold ( 6 ) and for recovering the gas from the injection mold ( 6 ), characterized in that in the transfer line ( 22 ) of the gas between the device ( 2 ) for increasing the source pressure of the gas to the working pressure and the injection mold ( 6 ) a component of the device ( 5 ) for transferring the gas under working pressure forming electrohydraulically pilot-controllable proportional valve ( 24 , 24 ') is integrated, to which the with a recovery compressor ( 72 ) and with different gas pressures set gas stores ( 53 , 54 ) Device ( 7 ) for gas recovery can be connected. 2. Control device according to claim 1, characterized denotes ge that with the transfer line (22) between the proportional valve (24, 24 ') and the mold (6) in the immediate vicinity of the injection mold (6) via control electronics (33) the proportional valve ( 24 , 24 ') couplable electrical pressure transducer ( 47 ) is ruled out. 3. Control device according to claim 1 or 2, characterized in that the proportional valve ( 24 , 24 ') a gas stage ( 25 ) with a spring-loaded conical sealing body ( 26 ) and matched sealing seat ( 27 ), an electrically actuated control valve ( 28 ), a hydraulic stage ( 29 ) with an actuating piston ( 31 ) which can be acted upon hydraulically via the control valve ( 28 ) against the restoring force of a spring ( 30 ) and with an actuating rod ( 32 ) which can act on the sealing body ( 26 ) and one with the actuating piston ( 31 ) connected and to the control electronics ( 33 ) coupled th transducer ( 35 ). 4. Control device according to claim 3, characterized in that the sealing body ( 26 ), the sealing seat ( 27 ) and the sealing body-side length section ( 36 ) of the actuating rod ( 32 ) are provided in an exchangeable valve cartridge ( 37 ). 5. Control device according to claim 3 or 4, characterized in that the sealing body-side length section ( 36 ) of the actuating rod ( 32 ) with a metallic sealing element ( 38 ) to interrupt the connection ( 41 ) between the working connection ( 39 ) of the gas stage ( 25 ) and the storage connection ( 40 ) connected to the device ( 7 ) for gas recovery is provided. 6. Control device according to one of claims 1 to 5, characterized in that the Einrich device ( 2 ) to increase the source pressure of the gas, a high pressure compressor ( 8 ) and a high pressure accumulator ( 9 ) between the high pressure compressor ( 8 ) and the proportional valve ( 24 , 24 ') has. 7. Control device according to claim 6, characterized in that the high pressure accumulator ( 9 ) is followed by a gas filter ( 23 ). 8. Control device according to claim 6, characterized in that the high pressure compressor ( 8 ), a pre-compressor ( 10 ) and possibly with the gas source ( 3 , 4 ) via a in the direction of the gas source ( 3 , 4 ) blocking check valve ( 21 ) connectable Vordruckspei cher ( 11 ) are connected upstream. 9. Control device according to claim 8, characterized in that between the check valve ( 21 ) and the gas source ( 3 , 4 ) a changeover valve ( 15 ) is seen before. 10. Control device according to one of claims 1 to 9, characterized in that the Einrich device ( 7 ) for gas recovery via an electrically operable switching valve ( 50 ) and a line ( 80 ) to the proportional valve ( 24 ) is connected. 11. Control device according to one of claims 1 to 9, characterized in that the Einrich device ( 7 ) for gas recovery via an electrically actuated switching valve ( 50 ) and a switching valve ( 50 ) upstream gas filter ( 81 ) to the transfer line ( 22nd ) is connected between the proportional valve ( 24 ') and the injection mold ( 6 ). 12. Control device according to claim 10 or 11, characterized in that the device ( 7 ) for gas recovery has a gas line ( 52 ) to the inter mediate valve ( 50 ) and the pre-compressor ( 10 ), a medium pressure accumulator ( 53 ) and a low pressure spei cher ( 54 ) each via electrically operable storage valves ( 57 , 58 ) and a gas line ( 52 ) with the atmosphere (A) connecting outlet valve ( 59 ) can be connected. 13. Control device according to claim 11 or 12, characterized in that between the switching valve ( 50 ) and the gas filter ( 81 ) with the gas line ( 52 ) via an electrically switchable throttle valve ( 74 ) connectable line ( 77 ) is connected. 14. Control device according to claim 12, characterized in that the gas source ( 3 , 4 , 79 ) on the one hand and a return line ( 69 ) between the low pressure accumulator ( 54 ) and the associated storage valve ( 58 ) on the other hand via an electrically actuated changeover valve ( 71 ) and the recovery compressor ( 72 ) to a return line ( 73 ) between the medium pressure accumulator ( 53 ) and the associated storage valve ( 57 ) are alternately connectable. 15. Control device according to claim 12 or 14, characterized in that the gas source ( 3 , 4 ) via an electrically actuated source valve ( 68 ) to the gas line ( 52 ) between the switching valve ( 50 ) and the pre-compressor compressor ( 10 ) can be connected . 16. Control device according to claim 12, characterized in that between the connections ( 61 , 62 ) of the low pressure accumulator ( 54 ) and the medium pressure accumulator ( 53 ) to the gas line ( 52 ) on the one hand and the connection ( 62 ) of the medium pressure accumulator ( 53 ) on the gas line ( 52 ) and the precompressor compressor ( 10 ) on the other hand in each case one in the direction of the switching valve ( 50 ) blocking check valve ( 64 , 65 ) is provided. 17. Control device according to claim 1 or one of the claims follow, characterized in that the high pressure compressor ( 8 ), the precompressor compressor ( 10 ) and the recovery compressor ( 72 ) are formed by a stage piston compressors with a hydraulic linear drive.