Abstract:
Isolating device ( 1 ) in particular for an injection valve ( 2 ), with a turning spindle ( 4 ), rotatably mounted in a device housing ( 3 ), actively connected to a drive device ( 5 ), for the variable displacement of an operating element ( 6 ) for an isolation stop valve ( 7 ), connected to the turning spindle, by means of a gearbox unit ( 8 ). The aim of the invention is to improve said isolating device such that the above may be operated in a simple and controllable manner, whereby the control of the isolating device may be carried out from a remote position and in a secure manner. Said aim is achieved, whereby the drive device ( 5 ) comprises at least two individually or synchronously operable electric motors ( 9, 10 ) and the gearbox unit ( 8 ) comprises at least one in particular self-locking drive unit ( 11 ), said drive unit ( 11 ) being connected to both electric motors ( 9, 10 ) for turning the turning spindle.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to an isolating device, in particular for an injection valve, with a turning spindle rotatably mounted in a device housing, actively connected to a drive device for the variable displacement of an operating element with an isolation stop valve connected to the turning spindle by means of a gearbox unit.  
           [0002]    Such an isolating device is known from practice, and is, for example, operated via a handwheel or the like. By turning the handwheel the turning spindle is set rotating via a gearbox unit arranged between the handwheel and a turning spindle, and the operating element with the isolation stop valve is moved towards the injection valve or away from it together with the turning spindle. By the isolation stop valve, the injection valve can be closed or the passage thereof can be varied.  
           [0003]    Corresponding isolating devices with hydraulic drive device are also known from practice. With these, corresponding feed or outlet lines for the hydraulic fluid to the isolating device, which are fixed to the device housing by means of corresponding connections, are necessary.  
           [0004]    In particular in oil mining, the injection valve serves for injecting chemical substances which prevent that, for example, when the crude oil cools down when it is exiting the oil well, constituents of the crude oil solidify and possibly deposit in the conveying device. In an extreme case, the deposition of these solidifying substances can result in a seal of the conveying device. As oil is also extracted at places difficult to access, such as below sea level, the operation of isolating devices known from practice is difficult. For example, the manually operated isolating device has to be operated near the ocean floor by a diver or a corresponding submersible vessel. With such a manual operation, moreover a check of the setting of the isolating device and thus the closing of the injection valve is not sufficiently possible.  
           [0005]    With the hydraulically operated isolating devices, it has to be noted that it is relatively complicated to supply them with hydraulic fluid and that corresponding connection lines have to be placed and connected to associated hydraulic fluid sources. If there is a leak at the corresponding hydraulic lines, the isolating device can no longer be correctly operated, and finding and repairing the leak is time-consuming and costly.  
         BRIEF SUMMARY OF THE PREFERRED EMBODIMENTS  
         [0006]    The object underlying the subject matter of the application is therefore to improve an isolating device of the above mentioned type, such that it may be operated in a simple and controllable manner, whereby the isolating device may be controlled from a remote position and in a secure manner.  
           [0007]    According to the invention, this object is achieved in connection with the features of the preamble of claim 1 in that the drive device comprises at least two individually or synchronously operable electric motors and the gearbox unit comprises at least one in particular self-locking drive unit, said drive unit being actively connected to both electric motors for turning the turning spindle.  
           [0008]    By the use of electric motors, the operation of the isolating device is considerably facilitated. A manual operation is no longer necessary. Similarly, hydraulic lines, a hydraulic fluid source and the further devices necessary for a hydraulic operation of such an isolating device can be dispensed with. With an electrically operated isolating device, no leak can occur in corresponding hydraulic lines, such that a maintenance and repair of such an isolating device according to the invention are considerably facilitated.  
           [0009]    The electric motors can be operated and controlled from a remote position. It is not necessary to arrange corresponding control devices, a hydraulic supply and the like, for example near the drilling hole, such as on a platform above sea level. The control can also be done from the land. This is analogously true for places difficult to access where drillings are performed.  
           [0010]    By using the self-locking drive unit and the driving connection thereof with the electric motors, it is achieved according to the invention that an automatic adjustment of the isolation stop valve of the isolating device is not possible, but that it is only possible after a corresponding release moment has been applied by one or both electric motors.  
           [0011]    According to the invention, it is possible to use the two motors redundantly, such that only one electric motor at a time operates the isolating device. It is also possible to operate both electric motors, in particular for applying a higher torque, synchronously and to employ them simultaneously for turning the turning spindle and thus for adjusting the isolation stop valve.  
           [0012]    The self-locking drive unit can be self-locking in both moving senses of the turning spindle. It is also possible for it to be, for example, only self-locking in the restoring direction of the turning spindle, thus preventing an automatic restoration c)f the isolation stop valve from its isolating position in the injection valve.  
           [0013]    A reliable and easily controllable motor is obtained if the electric motor is a servomotor, in particular a direct-current servomotor.  
           [0014]    For redundance reasons, it can be furthermore considered to be advantageous if each electric motor is electrically connected to a separate control device. The corresponding control devices are arranged remote from the isolating device, such that the electric motors and thus the isolating device can be operated in remote control.  
           [0015]    In order to be able to connect the electric motors to their control devices also separately from the outside, for each electric motor one electrical connection device may be formed at the device housing.  
           [0016]    The self-locking drive unit can have various designs. One example for such a drive unit is a ratchet or planet wheel gear as well as a volute spring. A self-locking drive unit easy to be manufactured and operated can be a worm gear pair consisting at least of worm and worm wheel, the worm wheel being associated to the turning spindle and the worm to the electric motors. Such a worm gear pair can be self-locking in both moving senses or only in one moving sense.  
           [0017]    In order to easily connect the worm gear pair to the electric motors, the worm can be arranged on a worm shaft actively connected to both electric motors.  
           [0018]    It is possible to associate both electric motors to one shaft end of the worm shaft and provide them essentially directly one behind the other on this worm shaft. In another possibility of arranging the electric motors, the same can be each actively connected to opposite shaft ends of the worm shaft.  
           [0019]    One example of such a driving connection may be that each electric motor is stationarily connected with its motor shaft to the respective shaft end. It is also possible for each shaft end in the electric motor to be stationarily arranged essentially as the motor shaft thereof.  
           [0020]    In order to fix the electric motors in the device housing in a simple manner, the electric motor can be stationarily held in the device housing by means of a ring nut.  
           [0021]    As a further safety measure for the operation of the isolating device and thus the injection valve, the motor shaft of at least one electric motor can be elongated at its end facing away from the worm shaft and movably connected at this end to an emergency release device. If both electric motors fail, the isolation stop valve can still be adjusted by means of the emergency release device.  
           [0022]    The emergency release device can be manually operated.  
           [0023]    A simple embodiment of an emergency release device may be that the same comprises at least one supporting sleeve stationarily held in the device housing and a spacing sleeve mounted to rotate relatively to said supporting sleeve, a releasable volute spring being wound on the outside as part of the self-locking drive unit. The volute spring stationarily connects the supporting sleeve and the spacing sleeve, and only after their release, the spacing sleeve can be rotated relatively to the supporting sleeve and thus the turning spindle can be rotated and the isolation stop valve adjusted by means of the movable connection between the spacing sleeve and the worm shaft.  
           [0024]    In order to be able to control the emergency release device even from a remote position, the volute spring can engage with one of its ends a release sleeve which is connected to an electric motor, in particular a stepper motor. By a remote-controlled operation of the stepper motor, the release sleeve can be rotated, the volute spring released via one of its ends and subsequently, the spacing sleeve can rotate relatively to the supporting sleeve. The volute spring can be wound up by the stepper motor.  
           [0025]    In order to securely mount the worm shaft and/or the motor shaft in the device housing even for high stresses, at least each shaft end can be rotatably held in the device housing by ball bearings and/or roller bearings.  
           [0026]    The worm wheel can be actively connected directly to the turning spindle. One example of such a driving connection is, for example, that the worm wheel is directly arranged on the turning spindle or as a part thereof. Another possibility for the driving connection between the worm wheel or worm, respectively, and the turning spindle can be that the worm wheel is arranged on a bearing shaft in moving connection with the turning spindle. In this manner, the bearing shaft is rotated by the engagement between the worm and worm wheel and this rotation is transmitted to the turning spindle via the driving connection with the turning spindle. Via the turning spindle, the operating element with the isolation stop valve can then be correspondingly adjusted.  
           [0027]    In order to be able to use a worm wheel having a relatively large diameter even with a low-diameter bearing shaft, a bearing sleeve can be arranged between worm wheel and bearing shaft. The same is stationarily connected to the worm wheel as well as to the bearing shaft.  
           [0028]    A simple possibility of a stationary connection between, for example, the worm wheel and bearing sleeve can be that the bearing sleeve and worm wheel are detachably connected by a spline connection and/or studs. The spline connection can be formed by a ratchet or the like. By the use of the worm gear pair, a corresponding multiplication between the rotation of the electric motors and the rotation of the turning spindle is already achieved. In order to even increase the multiplication, the gearbox unit can comprise a ball screw of at least one ball nut and the turning spindle as recirculating ball screw.  
           [0029]    In another embodiment, instead of a ball screw, a roller screw of at least one roller nut and the turning spindle is used as recirculating roller screw.  
           [0030]    In order to obtain a roller screw having a long service life, a high bearing strength and further advantages, such as a high reliability, a smooth run etc., the roller screw can be a planetary roller screw.  
           [0031]    For a simple bearing of the screw nut (roller nut, ball nut) in the device housing, the screw nut can be arranged in a bearing sleeve which is mounted to rotate in the device housing but cannot be axially displaced.  
           [0032]    If the turning spindle and the bearing shaft are arranged in series, a simple connection between them can be made in that the bearing shaft engages the end of the turning spindle facing it and is stationarily held therein. In order to be able to mount the bearing shaft or the bearing sleeve, respectively, in this connection in the device housing in a simple manner, at least one needle bearing can be arranged between the bearing sleeve and the device housing.  
           [0033]    Instead of a series arrangement of the worm gear pair and the ball screw and the additional use of a bearing shaft and bearing sleeve, in a further embodiment of the invention, there also is the possibility that at least at one end of the screw nut, an end gearing is arranged which is engaged with a gearing of the worm wheel. In this manner, a direct driving connection between the worm wheel and the screw nut is constituted.  
           [0034]    The assembly can be still facilitated by forming the end gearing by the worm wheel, such that the worm wheel is arranged essentially coaxially to the screw nut.  
           [0035]    In this connection, it can be considered to be favourable favorable for the worm wheel to be detachably fixed in particular to the screw nut. Thus, the worm wheel and the screw nut are two separate parts which, however, can be stationarily interconnected in a simple manner.  
           [0036]    The worm wheel and worm can have various designs. For example, the worm wheel can be a globoid worm wheel or a spur gear. The worm can also be an enveloping worm or a cylinder worm.  
           [0037]    In order to securely accommodate the bearing sleeve with the screw nut in the housing, the bearing sleeve can be rotatably mounted in the device housing by means of at least one thrust bearing.  
           [0038]    In order to be able to separately exchange or even manufacture and optionally maintain parts of the isolating device, the device housing can be modularly assembled from sub-housings, which are interconnected by means of studs, threaded rings or the like. Each sub-housing can be handled separately and can be assembled with the other sub-housings on the spot to form the isolating device. For example, one sub-housing can be provided for accommodating the drive device and worm gear pair, one sub-housing for arranging the ball screw, one sub-housing for accommodating the operating element etc.  
           [0039]    In particular if the isolating device is employed below sea level, it is advantageous for the sub-housing to be tightly interconnected.  
           [0040]    For the particular arrangement of a roller screw and a worm gear pair in an adequately compression-proof housing, the device housing can comprise a central body of metal, in particular aluminium aluminum or an aluminium aluminum alloy, in the central bore of which the screw nut is mounted and along which the turning spindle extends. The electric motors can also be accommodated in this central body, and it can be considered to be advantageous for the central body to comprise two motor openings radially opened to the outside, in each of which one electric motor is detachably fixed, wherein between the motor openings and essentially tangentially to the central bore, a connection opening for arranging the worm shaft and the worm extends. The connection opening can also be formed as radial extension of the central bore.  
           [0041]    In order to facilitate the access to the isolating device and in particular to the roller screw and worm gear pair, the central body can be detachably sealed by an end plate at one of its ends.  
           [0042]    In order to be able to exactly determine the position of the turning spindle and thus of the operating element or the isolation stop valve, respectively, within the isolating device from a position remote from the isolating device, a positioning sensor can be arranged in the end plate and associated to one end of the turning spindle. By means of the positioning sensor, one can determine to what extent the turning spindle moves away from or towards the sensor. Correspondingly, one can determine where the isolation stop valve is located relative to the injection valve.  
           [0043]    A simple possibility of mounting the isolating device at the injection valve can be that the device housing or a sub-housing, respectively, can be detachably mounted at an injection valve housing and that the isolation stop valve can be displaced transversely to a connection line within the injection valve housing between a fluid pump and a valve arrangement of the injection valve to the variable isolation of the connection line.  
           [0044]    In order to assist the restoration of the operating element and the isolation stop valve, within at least one sub-housing, a spring arrangement for applying force to the operating element or the turning spindle, respectively, in the starting position can be arranged.  
           [0045]    This spring arrangement can, for example, be formed by a Belville spring.  
           [0046]    If both electric motors are operated simultaneously, they have to be synchronised synchronized in their movement and in particular in their drive of the worm shaft. This car preferably be achieved by a software synchronization.  
           [0047]    The synchronization is facilitated and easier to control by switching one electric motor as master and the other electric motor as slave, or by switching both motors as master. In a case of emergency, the adjustment can also be effected by only one motor.  
           [0048]    In order to correspondingly supply the electric motors and further electric apparatuses of the isolating device from outside the device housing, an electrical passage for the electrical connection of the motors with their control devices can be arranged in the housings.  
           [0049]    If the isolating device is employed below sea level, the device housing can be filled with oil and compensated for a pressure compensation. In this connection, the compensation relates to a corresponding additional oil supply or oil withdrawal to the or from the device housing, for example in order to compensate changed temperature conditions.  
           [0050]    In order to reinforce the operating element, for example, the same can comprise a piston housing connected to a shaft section connected to the turning spindle.  
           [0051]    In order to determine in this connection the starting position of the operating element in a simple manner, the shaft section can be surrounded by an annular locknut which is screwed in the device housing for determining the starting position of the piston housing and thus of the operating element.  
           [0052]    For the spring arrangement to be able to support at one of its ends at the operating element to apply a force thereto in the starting position, the piston housing can comprise at its end facing the locknut an end flange radially projecting to the outside to which one end of the spring arrangement is adjacent.  
           [0053]    In order to seal the isolating device with respect to the injection valve when these are connected, the device housing can comprise sealing elements on its end face facing the injection valve for sealingly fixing it to the injection valve housing.  
           [0054]    Corresponding to the arrangement of the sub-housings, the various shafts, spindles or operating elements in the device housing can be also correspondingly subdivided and detachably interconnectable. This is preferably done in that the bearing shaft, turning spindle and operating element are arranged essentially coaxially and are detachably interconnected at their facing ends.  
           [0055]    In order to further increase the multiplication, a so-called harmonic drive can be arranged between the worm gear pair and the ball screw. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0056]    Advantageous embodiments of the invention are illustrated with reference to the Figures enclosed in the drawing as follows.  
         [0057]    In the drawings:  
         [0058]    FIG. FIG. 1 shows a plan view onto a first embodiment of an isolating device;  
         [0059]    FIG. FIG. 2 shows a section along the line II-II of FIG. FIG. 1 with a partially represented injection valve;  
         [0060]    FIG. FIG. 3 shows a section along the line III-III of FIG. FIG. 1 or FIG. FIG. 2, respectively;  
         [0061]    FIG. FIG. 4 shows a plan view onto a second embodiment of an isolating device according to the invention;  
         [0062]    FIG. FIG. 5 shows a section along the line V-V of FIG. FIG. 4 or  6 , respectively, and  
         [0063]    FIG. FIG. 6 shows a section along the line VI of FIG. FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0064]    In FIG. FIG. 1, a plan view onto a first embodiment of an isolating device  1  according to the invention is represented. It comprises a device housing  3  of various sub-housings  47 ,  48 ,  49  and  50 . The sub-housings are detachably interconnected. Studs  51  or a threaded ring  52 , respectively, serve for the detachable connection. In the sub-housing  57 , in particular a drive device  5  with two electric motors  9  and  10  is arranged. These are arranged at both ends of a worm shaft  19  on which approximately centrically a worm  17  is provided.  
         [0065]    An emergency release device  26  is associated to one electric motor  9 , which device can be actuated by an electromotor  52 .  
         [0066]    On one upper side of the sub-housing  47 , a connection device  14  is arranged via which the electric motors and the electromotor can be connected with remotely arranged control devices  12  and  13 , respectively.  
         [0067]    The sub-housing  47  is detachably sealed by an end plate  59  adjacent to the connection device  14 . Another sub-housing  50  is placed thereupon and contains in particular a positioning sensor, see for example FIG. FIG. 2.  
         [0068]    In FIG. FIG. 2, a section along the line II-II of FIG. FIG. 1 is represented. In this Figure as in the other Figures, same parts are provided with the same reference numerals and are therefore only partly described.  
         [0069]    In FIG. FIG. 2, in addition to the isolating device  1 , an injection valve  2  with a corresponding injection valve housing  61  is represented. The same can be fixed at one end of the isolating device  1  by means of a threaded sleeve  80 . In this case, the two housings are sealed relative to one another via sealing elements  79  which are arranged in an end face  78  of the device housing  3  of the isolating device  1 .  
         [0070]    The injection valve  2  essentially comprises a connection line  62 , which is connected on the one hand with a fluid pump  63  and on the other hand with a ball valve  86  as a valve arrangement  64 . An isolation stop valve engages the connection line  62 , such that the connection between the pump  63  and the valve arrangement  64  is interrupted. By shifting the isolation stop valve  7  out of the isolating device  1 , a slider opening  85  of the isolation stop valve  7  can be arranged in the connection line  62 , which more or less constitutes a connection between the pump  63  and the valve arrangement  64  depending on the positioning of the slider opening  85 .  
         [0071]    The isolation stop valve  7  is arranged at the end of an operating element  6  extending through the device housing  3  of the isolating device  1  from the injection valve housing  61  towards a gearbox unit  8  consisting of screw  39  and worm gear pair  16 .  
         [0072]    The operating element  6  comprises, apart from the isolation stop valve  7 , an end part  92  represented in FIG. FIG. 2 in broken lines, which part is engaged by a shaft  93 . The same is arranged within a piston housing  71  and connected to a shaft section  72  at its end opposite the end part  92 . The piston housing  71  is fixed thereto arid there comprises an end flange  76  radially extending to the outside. One end  77  of a spring arrangement  65  is supported on this end flange  76 , the other end being supported on the sealing body  93  of the device housing  3 . The threaded sleeve  80  is rotatably mounted around the sealing body  93  and can be screwed upon a side extension  87  of the injection valve housing  61 .  
         [0073]    In FIG. FIG. 2, the piston housing  71  is represented in a starting position  74 , in which the end flange  76  is adjacent to a locknut  73  screwed into the sub-housing  49 .  
         [0074]    The threaded ring  52  serves for connecting the sub-housings  49  and  48  and is notatably mounted at the sub-housing  48  and screwed upon the sub-housing  49  from the outside.  
         [0075]    In the sub-housing  48 , a screw  39  is arranged as part of the gearbox unit  8 .  
         [0076]    The screw  39  is formed of a screw nut  40 , in this case a revolving roller nut, and the turning spindle  4 , forming together a planetary roller screw. At its end  69  facing the operating element  6 , the turning spindle  4  is inserted into a hole at the end  70  of the operating element  6  or the shaft section  72 , respectively, and held therein by means of a bolt. The screw nut  40  is rotatably, but axially stationanily arranged in a bearing sleeve  42 . The end  69  of the turning spindle  4  projects from the bearing sleeve  42  in the direction of the operating element  6 .  
         [0077]    Opposite to the end  69 , the turning spindle  4  projects with its other end  69  from the screw nut  40  and is there also surrounded by a section of the lower-diameter bearing sleeve  42 . At the outside of this section, the bearing sleeve  42  is rotatably mounted in the device housing  3  or in the sub-housing  48 , respectively, by means of a needle bearing  44 .  
         [0078]    A bearing shaft  55  passes through the bearing sleeve  42 , the end  68  thereof being inserted in the end  43  of the turning spindle  4  and being stationanily held therein.  
         [0079]    In FIG. FIG. 2, the turning spindle  4  is represented in its starting position  66 , i.e. as far as possible inserted through the screw nut  40  in the direction away from the injection valve  2  into the device housing  3 .  
         [0080]    In another embodiment according to FIG. FIG. 2, it is also possible for the screw nut  40  not to be arranged in the interior of the device housing only stationanily with respect to axial displacements but also to rotations via the bearing sleeve  42 . In this case, the turning spindle  4  is rotated directly by the connection to the bearing shaft  35 .  
         [0081]    In the sub-housing  47 , essentially the bearing shaft  35  and a drive device  5 , also see FIG. FIG. 3, for the isolating device  1  are arranged. The bearing shaft  35  is arranged in a bearing housing  36 , which is stationanily connected to a worm wheel  18  as part of the worm gear pair  16  via a spline connection. The worm wheel  18  is a globoid worm wheel and engaged with its gearing with a worm  17 .  
         [0082]    The bearing sleeve  36  is rotatably mounted in the sub-housing  47  via needle bearings  44 . The latter is detachably connected to the sub-housing  48  via studs  51 . At the end of the sub-housing  47  opposite to the sub-housing  48 , the same is detachably sealed by an end plate  59 . A hood-like sub-housing  50  is placed onto the end plate  59  and detachably connected thereto. In the sub-housing  50 , a positioning sensor  60  is arranged and fixed there by means of a supporting ring and corresponding screws  93 ,  94 .  
         [0083]    Between the worm gear pair  16  and the screw  31 , a so-called harmonic drive  102  is arranged as further part of the gearbox unit  8  for further increasing the multiplication.  
         [0084]    In the end plate  59 , electrical passages  67  are arranged via which the electrical connection of devices arranged within the sub-size  47  is effected, see FIG. FIG. 3.  
         [0085]    In FIG. FIG. 3, a section along the line III-III of FIGS. FIGS. 1 and 2, respectively, is represented. The sub-housing  47  is essentially formed of a massive central body  53  in which a central bore  54  is formed. In this bore, see FIG. FIG. 2, the bearing sleeve  36  is rotatably mounted.  
         [0086]    The worm wheel  80  is stationarily connected to the bearing sleeve  36  via the splined shaft connection  37  in the form of a ratchet. The same is engaged with its external gearing in a corresponding external gearing of the worm  17 . The worm  17  is arranged on a worm shaft  19  which extends approximately tangentially to the central bore  54 .  
         [0087]    Shaft ends  20 ,  21  of the worm shaft  19  are rotatably mounted by means of a ball bearing  33  or a roller bearing  34 , respectively. An electric motor  9 , 10  of the drive device  5  is associated to each of the ends  20 ,  21  of the worm shaft  19 . The electric motor  9  is directly actively connected with the shaft end  20  or a motor shaft  22 , respectively, and is detachably mounted in a motor opening  55  in the central body  53 . The mounting is effected in this connection via a ring nut  24  which is screwed in within a supporting sleeve  27 . The supporting sleeve  27  is fixed in the motor opening  55  via screws  95 .  
         [0088]    One end  25  of the motor shaft  22  extends beyond the electric motor  9 , which is designed as a servomotor and in particular as a direct-current servomotor as is the other electric motor  10 , along a narrowed section of the supporting sleeve  27 . The end  25  of the motor shaft  22  is rotatably mounted in this narrowed section of the supporting sleeve  27 .  
         [0089]    The motor shaft  22  extends beyond the supporting sleeve  27  into a spacing sleeve  28  and is fixed by a nut at its end. The spacing sleeve  28  is stationarily connected to the supporting sleeve  27  in one sense of rotation via a volute spring  29  wound up at its outer sides with the volute spring being tense. With one of its ends  30 , the volute spring  29  engages a release sleeve  31 , which is rotatably mounted with respect to the spacing sleeve  28  and the supporting sleeve  27 .  
         [0090]    The release sleeve  31  is actively connected to a drive shaft of an electromotor  32  via a pin connection. This electromotor is designed as a stepper motor. The electromotor is arranged in a side housing  26  in the extension of the motor opening  55 . The side housing  96  is detachably sealed by a cover  82 .  
         [0091]    The other electric motor  5  is also detachably held in a motor opening  56  by means of a mounting  97  and a ring nut  24 . The motor shaft  23  is connected to the end  21  of the worm shaft  19  or is formed as a part thereof and extends through the electric motor  5  beyond its end opposite of the worm shaft  19 . There, the motor shaft is held by a spacing ring and a nut.  
         [0092]    In a cover  98  of the connection opening  57  connecting the motor openings  55  and  66 , a plug  83  is arranged, also see the other plugs, for example in FIG. FIG. 2.  
         [0093]    Moreover, a spiral spring  102  is connected to the side housing  26  which is in particular detachably connected with an inner end to the side housing  26  and with an outer end to a ring flange surrounding the side housing while being spaced therefrom.  
         [0094]    In FIG. FIG. 4, a plan view onto a second embodiment of an isolating device  1  according to the invention is represented. The same also comprises a device housing  3  consisting of sub-housings  58 ,  59  and  50 . An end plate  59  onto which the sub-housing  50  is screwed is arranged between the sub-housings  48  and  50 . The end plate  59  is also detachably mounted to the sub-housing  48  by screwing. In the area of the end plate  59 , two connection devices  14 , 15  for electrical connection lines for the supply and for controlling the drive device are arranged, see FIGS. FIGS. 5 and 6. Electrical connection lines extend from the connection devices up to the control device  12 , 13 . These are arranged at a remote position and serve for the remote-controlled operation and control of the isolating device  1 , also see FIG. FIG. 1.  
         [0095]    At the sub-housing  49 , a corresponding threaded sleeve  80 , see FIG. 5, is not depicted for simplification reasons. It is retained at the sub-housing  49  by a support ring  99  and is rotatably mounted there.  
         [0096]    FIG. FIG. 5 is a section along the line V-V of Fi. FIG. 4.  
         [0097]    The difference to the isolating device  1  according to the first embodiment is essentially that the worm wheel  18  is directly movably connected to the screw nut  40  and detachably mounted to the end  45  thereof. The turning spindle  4  extends through the screw nut  40 , in this case, too, the screw  39  formed of screw nut  40  and turning spindle  4  being designed as a planetary roller screw.  
         [0098]    The screw nut  40  is stationanily mounted in the bearing sleeve  42 , being connected thereto via studs  89  which at the same time stationarily connect the worm wheel  18  to the screw nut  40 . The bearing sleeve  42  is mounted by thrust bearings  41  in the central body  53  forming the sub-housing  48  rotatably but stationarily with respect to axial displacement. The axial fixation within the central body  53  is effected by a ring nut  88  which is screwed-upon the bearing sleeve  42  from the outside.  
         [0099]    Between the thrust bearing  41  and the central body  53 , a retainer ring  91  which fixes the thrust bearing  41  is moreover arranged.  
         [0100]    The central body  53  is approximately cuboid, also see FIG. FIG. 6, and comprises the central bore  54  in which the screw nut  40  and the bearing sleeve  42  are rotatably mounted. The central bore  54  is detachably sealed at the upper end in FIG. FIG. 5 by the end plate  59  by means of studs  51 . The electric passage  67  is arranged in the end plate  59 .  
         [0101]    At an outer side of the end plate  59 , the further hood-like sub-housing  50  is arranged, also see FIG. FIG. 2. Between this and the end plate  59 , the positioning sensor  60  is arranged. The positioning sensor is mounted analogously to FIG. FIG. 2.  
         [0102]    The turning spindle  4  is fixed thereto at its end  69  facing the operating element  6  by inserting a corresponding end  70  of the retaining element  6  into a bore at the end  69  of the spindle  4  and fixing it therein by a stud.  
         [0103]    The operating element  6  extends through the further sub-housing  49  beyond the same, a corresponding isolation stop valve, see FIG. FIG. 2, not being depicted in FIG. FIG. 5 for simplification reasons.  
         [0104]    In the end face  78  of the sub-housing  49  to be associated to the injection valve  2 , sealing elements  79  are arranged in the form of  0 -rings.  
         [0105]    FIG. FIG. 6 corresponds to a section along the line VI-VI of FIG. FIG. 5.  
         [0106]    The central body  53  in turn comprises the two motor openings  55  and  56 , also see FIG. FIG. 3, in each of these openings, one electromotor  9 , 10  being fixed by means of supporting rings  97  and ring nuts  24 . The connection opening  57 , in which the worm shaft  19  with worm  17  is arranged, extends between the motor openings  55  and  56 .  
         [0107]    Shaft ends  20 ,  21  of the worm shaft  19  are in turn rotatably mounted in the motor openings  55 ,  56  by means of ball bearings  33  or roller bearings  34 , respectively. The corresponding bearings  33 ,  34  are held by the electric motors  9 , 10  via spacing disks  100 .  
         [0108]    The motor shafts  22 ,  23  are in turn stationanily connected to the shaft ends  20 ,  21  or integrally formed therewith. The motor shafts  22 ,  23  are mounted with respect to the electric motors  9 , 10  via studs with corresponding spacing disks.  
         [0109]    Analogously to the first embodiment, it is possible to associate an emergency release device  26  to at least one of the electric motors  9 , 10 . The same can be operated electrically or manually. The manual operation can, for example, be effected via a pin  101  extending transversely at the motor shaft  23  and it can be engaged with a non-depicted operating device. This operating device would be inserted into the opening sealed by the end plate  81 .  
         [0110]    In the following, the functioning of the isolating device according to the invention is illustrated in brief with reference to the Figures.  
         [0111]    In both embodiments, a self-locking drive unit  11  is used, which is formed in the embodiment according to FIG. 2 by an additional volute spring  29  with corresponding sleeves  27 ,  28 ,  31 , and in the embodiment according to FIG. 5 by the worm gear pair  16 . This drive unit comprises the worm shaft  19  which is actively connected at both ends each with an electric motor  9 , 10 . The two motors can be operated individually or also synchronously relative to one another. With a corresponding operation of the electric motors  9 , 10 , the worm shaft  19  and thus the worm  17  rotate. Via the engagement with the worm wheel  18 , the same rotates corresponding to the worm  16  with a corresponding multiplication. The worm wheel  18  rotates either directly, see FIG. FIG. 5, or via the bearing sleeve  36 , see FIG. FIG. 2, the screw nut  40 , the turning spindle  4  is again rotated therein with a corresponding multiplication. As the screw nut  40  is axially fixed in the corresponding device housing  3 , by the rotation of the turning spindle  4 , the same is also adjusted in the longitudinal direction of the device housing  3 . Corresponding to the rotation of the turning spindle  4 , the operating element  6  with the isolation stop valve arranged thereon is also adjusted. Depending on the adjustment of the operating element  6 , the connection line  62  in the injection valve  2  is closed or more or less opened by the isolation stop valve  7 .  
         [0112]    When the connection line  72  is opened or partially opened, corresponding fluid is dispensed from the fluid pump  63  via the valve arrangement  64  to further, non-depicted devices.  
         [0113]    The restoration of the isolation stop valve  7  into its starting position or of the turning spindle  4  into its starting position can be effected via corresponding reverse operations of the electric motors  9 , 10 , the operation thereof being assisted in the embodiment according to FIG. FIG. 2 by applying a corresponding force to the spring arrangement  65 .  
         [0114]    If the electric motors fail, the self-locking of the drive unit  11  can be furthermore overcome by a corresponding emergency release device  26 , see for example FIG. FIG. 3.  
         [0115]    By means of the isolating device according to the invention, in particular with a synchronous operation of both electric motors, this synchronization being effected with software with at least one electric motor as master and the other electric motor as slave, a high torque with high multiplications can be transmitted by the corresponding gearbox unit consisting of worm gear pair  16  and screw  39 . Moreover, the isolating device can be controlled from a remote position without complicated constructions for the control and supply of the corresponding device near the actual drilling site in oil mining or the like having to be arranged.