US3368101A - Means for introducing objects in an isolated enclosure - Google Patents

Description

Feb. 6, 1968 J. ROMAND ET AL 3,368,191

MEANS FOR INTRODUCING OBJECTS IN AN ISOLATED ENCLOSURE Filed June 22, 1964 3 Sheets-Sheet 1 J. L. ROMAND ET AL 3,368,101

MEANS FOR INTRODUCING OBJECTS IN AN ISOLATED ENCLOSURE v Feb. 6, 1968 Filed June 22, 1964 SSheets-Sheet 2 Feb. 6, 1968 J. L. ROMAND ET AL 3,368,101

MEANS FOR INTRODUCING OBJECTS IN AN I SOLATED ENCLOSURE Filed June 22, 1964 3 Sheets-Sheet 5 1' Q Q a; u.

3,368,101 MEANS FOR INTRODUCING OBJECTS IN AN ISOLATED ENCLOSURE Jacques Louis Remand, BourgJa-Reine, and Boris Vodar and Jean Martin, Paris, France, assignors to Centre National de la Recherche Scientifique (French Government Administration), Paris, France Filed June 22, 1964, Ser. No. 376,882 Claims priority, application France, June 25, 1963, 939,304 11 Claims. (Cl. 314-1) This invention relates to transporting devices and more specifically to devices for inserting an object in a gasfilled or evacuated container without disturbing the characteristics of the medium therein.

Many industrial and research operations require the introduction of an object or a test sample into an enclosure containing a gaseous medium whose composition and/or pressure differ from those of the medium outside the container. For such operations it is often desirable, if not essential, that the medium within the enclosure not be disturbed.

This condition is particularly important in spectographic analysis since test sample electrodes must be introduced into the chamber of the spectroscope while, for each test run, the vacuum pressure is maintained at a predetermined value in order to permit the production of uniform arcs and, hence, the achievement of accurate and repeatable results.

It is therefore an object of this invention to introduce an object into a container without disturbing the medium therein.

It is another object of this invention to accomplish such introduction using relatively simple means.

It is a further object of this invention to accomplish such introduction by a simple and rapid procedure.

Although the physical embodiments of the present invention disclosed herein are shown in connection with a spectroscope, it should be understood that this is only by way of example and that the present invention may equally well be used with any other device requiring the performance of a similar operation under similar circumstances.

The preferred embodiments of the present invention essentially comprise:

A piston which is slidably and rotatably movable within a cylinder which isrigidly attached to the wall of the enclosure, said piston communicating with the interior there of by means of a circular, off-center opening arranged in the base of the cylinder and closing the cylinder at the end within the enclosure, said piston being pierced by a longitudinal passage which is displaced from the cylinder axis by a distance equal to the radial displacement of said offcenter opening from this axis, the longitudinal passage being designed to receive objects which are to be introduced into the enclosure, the interior end of this passage being capable of being placed, by means of both translational and rotational movements of said piston, either adjacent to said opening or against an air tight seating formed in said cylinder base;

A closure system acting on the outer extremity of said passage and capable of assuming, with respect to the piston, either a first position in which said outer extremity of said passage is open to permit objects to be placed in said passage, the interior end of the passage then being in contact with said seating, or a second position in which the closure system seals the outer extremity of said passage, the closure system comprising means for pushing objects in said passage into said enclosure after the piston has been rotated into a position where it is adjacent to said opening in said cylinder base; and

States Patent 3,358,1M Patented Feb. 6, 1968 ice thereof. These members are preferably maintained away from the longitudinal path in order to prevent them from contaminating the test samples.

The above described device is also intended to be used with auxiliary units which will preferably be operated at the same time and which will be described in detail at a later point herein.

The present invention is particularly directed to a certain use of the above described structure, as well as particular forms of construction thereof, and more particularly to the structures embodying the present invention and the combination of these structures with suitable systems for carrying out various multi-step processes in an enclosed space.

These and other advantages, objects and features of the present invention, will become more readily apparent from the following etailed description when taken together with the accompanying drawings, in which:

FIG. 1 is a partially cross-sectional view of a spectroscope representing one preferred embodiment of the present invention, the plane of the view being taken perpen dicular to the axis along which the radiation from the sample is observed;

FIGS. 2 and 3 show longitudinal cross-sectional views of one embodiment of a subcombination of the present invention shown in two different operating states;

FIGS. 4 and 5 show cross-sectional views, taken along respective mutually perpendicular planes, and in two different operating states, of another subcombination of the present invention.

On the drawings the same numeral is used to identify the same element appearing in several figures.

According to the present invention, it is proposed to construct a device for introducing into the spectroscope chamber 1 of FIG. 1 an electrode 2 constituted by a test sample which is to be submitted to a spectroscopic analysis.

The spectroscope chamber 1 is here shown, by way of example, as being in the form of a horizontal cylinder. The view of FIG. 1 is taken perpendicular to the cylinder axis, which axis coincides with the line along which one observes the spectrum produced by the test sample. The vertical direction in the plane of FIG. 1 is shown by line X-X.

In front of the plane of FIG. 1 the chamber 1 is furnished with a flat base plate which is readily removable to permit the cleaning and general maintenance of the elements therewithin. To the rear of this plane the chamber is provided with a second base in which is formed the entry slit 1a for the spectrograph. In order to produce the necessary degree of vacuum within the chamber 1, it is provided with a pump orifice 1b which will be connected to a suitable vacuum pump (not shown), any known type of vacuum pump being suitable for this purpose.

In order to generate an arc, chamber 1 com-prises an arrangement well known to the prior art which consists of a current input 3 electrically connected to electrode 2 through the intermediary of 'an electrode-carrying slip 2a composed of two semicylindrical halves 20 which are pressed toward one another, and hence against electrode 2, by a fiat spring 2b, as well as an arc initiating element 4 supported by a post 6 which is electrically grounded, the arc initiating element being formed by a common cathode 5 electrically grounded and, by an interior electrode or starting anode 7, connected to an electrically isolated and air tight current output terminal 7a.

In order to prevent any variation in the composition or pressure of the gas Within chamber 1 at the time of 3 an insertion of a new electrode 2, the chamber is furnished with an electrode insertion unit which represents a preferred embodiment of the present invention and which extends through a circular opening 14 in chamber 1, the opening being defined by flange 15. This unit is shown in detail in FIGS. 2 and 3.

The spectroscope is also furnished with a unit passing through chamber opening 38 for correctly positioning electrode 2 for each spectrogram and for causing the test sample to be released from clip 2a when it is desired to change electrodes, and with a unit in communication with chamber opening 51a for recovering electrodes after their release from clip 2a. and for permitting the recovery of these electrodes without disturbing the chamber atmosphere. One form of this latter unit is shown in FIGS. 4 and 5.

Turning now to the sample introduction unit which is the subject of the present invention, FIGS. 2 and 3 show a piston 8 which is both rotatable and longitudinally slidable in a cylinder 9 immovably attached to chamber 1 and communicating with the interior of this chamber through an off-center circular opening 10 arranged in the base of the cylinder, the cylinder axis being indicated by the broken line Y-Y. The piston 8 is pierced by a longitudinal passage 11 whose axis is displaced from line Y-Y by the same distance as is the axis of opening 10. The passage 11 is designed to receive electrodes 2 which are to be introduced into chamber 1. The inner end 11a of this passage is capable of being placed, by means of rotations of piston 8, either in contact with an air tight seating 12 or adjacent the opening 10. When the piston is in this latter position, it may be slid forward so as to move passage end 11:: further into chamber 1.

The unit also comprises a closing assembly which cooperates with the outer extremity 11b of passage 11 and which is movable in such 'a manner that it can either be clear of extremity 11b so as to permit the introduction of test samples into housing 11 (as shown in FIG. 3), at which time inner extremity 11a abuts against seating 12, or it may be in a closing position where it seals extremity 11b, thus isolating passage 11 from the exterior (FIG. 2). Means are also provided which, when the assembly is in its closing position, can be manipulated to urge the electrode 2 in housing 11 into the interior of chamber 1, after piston 8 has been rotated so as to be pposite opening 10.

In the specific structure shown in FIGS. 2 and 3, the cylinder 9 is rigidly fastened in chamber opening 14, the opening being bordered by a flange 15 against which abuts a sholulder 16 provided on the outer wall of cylinder 9, the imperme'ability of the joint being assured by an annular seal '17. Then end of cylinder 9 directed towards the inside of chamber 1 is partially closed by a plate 18 which carries an impermeable seating 12 and an opening 10, both of which are circular and are placed diametrically across from each other symmetrically with respect to the axis YY of the cylinder.

The piston 8 is free to slide longitudinally and to rotate in cylinder 9 while maintaining an impermeable contact with the cylinder with the aid of annular seals 20, and it carries, on its face directed towards the interior of chamber 1, an off-center extension 21 forming a tube the extremity of which defines the end 11a of passage 11. The extension 21, whose outer diameter matches the diameter of opening 10, can either extend through opening into the interior of chamber 1 (FIG. 2) or can abut against seating 12 (FIG. 3), the latter position causing the end 11a of passage 11 to be sealed so as to completely isolate chamber 1 from the exterior, this sealing being effected by the abutment of the extremity of extension 21 against seating 12, the abutment being rendered air tight by the flexible annular seal 19. Seal 19 has an internal diameter which is greater than that of passage 11 so that, during the periods when the extension 21 abuts against the seal, electrodes placed in the passage will not be in danger of being contaminated by contact with this seal, such contact being often capable of causing contamination because the seal members are often supplied with a lubricant. At the opposite, or outer, end 11b of the passage, the piston 8 is furnished with a boss 22 containing a pin 13 from which is pivotally mounted the passage closing assembly contained within a housing 23 and comprising an extension 24- directed towards piston 8. A canal 25 passes longitudinally through said housing so that one end of the canal opens onto the extremity of extension 24 and the other end communicates with an aligned passage in a vacuum pump connection 26 attached to the end of housing 23 furthest removed from extension 24.

The extension 24 is so designed that when it is in its closing position it forms, in cooperation with seal 27, an air tight joint with the extremity 11b of housing 11. Seal 27 is mounted away from the path to be followed by electrode 2 or by mechanical pushing means in order to eliminate any possibility that the electrode might be contaminated by contact with the seal. An impermeable contact is assured between housing 23 and connection 26 by seals 21a. Mechanical electrode pushing means are provided in the form of a shank 28 carried on a toothed rack 29 which is capable of being moved along canal 25 under the action of a pinion 30w driven by an external hand crank 30 by means of a shaft which extends in an air tight manner through the wall of housing 23. The locking of housing 23 in its closed position is assured by a bolt 31 which is manipulated by handle 32 and which bears against the front wall of the boss 22 of piston 8 (see FIG. 2). With bolt 31 in this position, any attempts to rotate housing 23 would be opposed.

The device just described functions in the following manner: Assuming first that the device is in the position shown in FIG. 2, the extension 21 of piston 8 extends through opening 10 into the interior of chamber 1, the canal 25 is in communication with, and aligned with passage 11, and the same vacuum exists in chamber 1, passage 11 and canal 25. It is then possible to cause shank 28 to move electrode 2 into chamber 1 and between the halves of clip 2a into the position shown in FIG. 1.

When this operation is completed, the shank will be withdrawn back into canal 25, the assembly of piston 8 and cylinder 9 will be slid backward until the end 11a of extension 21 is fully within housing 23, which condition will be indicated by the abutment of a shoulder 33 on piston 8 against an annular stop member 34 carried on cylinder 9. Stop member 34 has one sector removed so as to permit the correct operation of the device. The pistonhousing assembly is then rotated by 180 around axis Y-Y so that end 11a is placed opposite, but out of contact with, seating 12. When the force applied to slide the assembly backward is then released, the pressure diiference between the normal atmosphere and the vacuum inside chamber 1 will act on piston 8 so as to force end 11a against seating 12. At this time, the passage 11 is completely isolated from the interior of chamber 1 and air is permitted to enter passage 11 and canal 25 through connection 26. The bolt 31 is unlocked by a rotation of handle 32 (counterclockwise in FIG. 2) and the housing 23 is rotated about pin 13 into the position shown in FIG. 3. In this position the unit is prepared to receive a new electrode 2 for introduction into chamber 1. In order to avoid any possible damage to the unit as a result of the conceivable rotation of housing 23 around pin 13 before the withdrawal of shank 28 into canal 25, a safety device has been provided to render impossible any movement of handle 32 before the complete withdrawal of shank 28.

When a new electrode 2 has been introduced, housing 23 is rotated back into its closing position so that extension 24 bears against end 11b of extension 21, bolt 31 is placed in its locking position, a vacuum pump is connected to the end of connection 26 and is operated so as to produce a vacuum in canal 25 and passage 11, piston 8 and housing 23 are pulled backward by a small amount so as to permit extension 21 to clear seating 12, the unit is rotated by 180 around axis YY so as to bring end 11a of passage 11 into alignment with opening 10, and the assembly is allowed to slide forward, under the effect of the vacuum in chamber 1, causing extension 21 to enter the interior of chamber 1 until piston 8 abuts against the inner wall 18 of cylinder 9. The unit is then once again in the condition shown in FIG. 2.

After the placement of each electrode in clip 2a, extension 21 is retracted into cylinder 9 and piston 8 is rotated until end 11a is opposite seating 12 before the commencement of an analysis run in order to eliminate any risk of an are damaging extension 21, or the production of a short circuit through extension 21.

In order to properly position an electrode in the chamber, and in order to open and close clip 1 to permit it to receive new electrodes and release used ones, means are provided which are illustrated in FIG. 1. Within chamber 1 is provided a shaft 35 the interior extremity 36 of which is in the form of a screw driver blade or similar flattened shape. The shaft 35 may slide within a guide 37 placed in an opening 38 in chamber 1, this opening being approximately diametrically opposed to chamber opening 14 and the shaft 35 being essentially parallel with, but axially displaced from, passage 11. Opening 38 is closed by a plate 39 and the impermeability of the joint between chamber 1 and this plate is assured by an appropriate seal 40. Another seal 41 assures the impermeability of the joint between shaft 35 and guide 37. Externally of chamber 1, shaft 35 is terminated by a curved extremity 42 which extends radially from an external guide tube 43. Guide tube 43 is furnished with a pair of notches 44a and 44b in which the curved end 42 of shaft 35 may be engaged in order to place the inner end 36 of shaft 35 into any one of several predetermined positions. Near its end 36, the shaft 35 carries a disc 45 disposed perpendicular to the direction of displacement of the shaft and provided with a peripheral ramp, or cam, 46, the purpose of which will become apparent from the following description of the operation of the above described device.

Prior to the introduction of an electrode into chamber 1, shaft 35 is placed in a position in which its curved end 42 is seated in notch 44a and in which its inner end 36, in the form of a screw driver blade, is inserted between elements of clip 2a.

Electrode 2 is at this time introduced into the chamber and is forced between clip elements 20, under the urging of shank 2.8, so that it spreads these elements apart and advances between them until its leading edge comes in contact with disc 45. The electrode is then correctly positioned. Shaft 35 may then be withdrawn as far as possible and locked in its retracted position with its end 42 engaging notch 44b. The extension 21 of piston 8 may also be retracted and seated in seating 12. The spectroscope is now prepared to obtain spectrograms of the electrode material.

After one or several test runs, when it is desired to work with a new electrode, the shaft 35 is first returned to its advanced position where end 42 engages notch 44a and screw driver blade 36 is inserted between elements 2c of clip 2a. In order to free electrode 2 from the clip, it is only necessary to rotate shaft 35 through a small angle, 45 for example, so that blade 36 spreads the two halves 2c apart, while at the same time the camming periphery 46 of disc 45 bears against the front end of electrode 2 so as to exert a sufficient transverse force to cause it to disengage from the clip 2a.

The spent electrode will then fall into the recovery device indicated generally by reference numerals 47, 48, 49, 50 in FIG. 1 and shown in detail in FIGS. 4 and 5. Referring specifically to FIGS. 4 and 5, one preferred embodiment of the recovery device is shown to have a recovery funnel 47 disposed directly below clip 2a and mounted on an air lock 48 which is inclined with respect to the vertical, indicated by line X-X, and which is placed below funnel 47. Air lock 48 comprises a receptacle 49, which may be made of a transparent material, or with transparent sections, and which is intended to serve as a temporary storage container for used electrodes. Receptacle 49 is maintained in place with respect to air lock 48 by means of a readily detachable stirrup element 49a. The recovery unit is attached to chamber 1 by means of a cylindrical extension 50 of connecting element 53 which is rigidly mounted in contact with the inner cylindrical wall of an opening 51. The opening 51 ends in a flange 51a which is impermeably joined to connecting element 53. The impermeability of the conr nection is assured by interposal seal 52. In a like manner,

seals 54 assure the air-tightness of the joints between air lock 48 and the elements connected at each of its ends.

Air lock 48 comprises a hollow internal region 55 which can communicate with the interior of chamber 1 by way of passage 50a passing longitudinally through the connecting element 53 and its extension 50. This communication may be interrupted by the rotation of plug 56 against seal 60 so as to impermeably isolate region 55 from passage 50a, which rotation is effected from outside air lock 48 by means of rotating lever 57 whose passage through the wall of air lock 48 in an airtight manner is assured by seal 61. Internal region communicates with receptacle 49 through a permanently opened opening 58, the impermeability of the connection between elements 48 and 49 being assured by annular seal 59. Finally, a vacuum pump orifice 48a is provided in air lock 48 in communication with region 55 so as to permit the latter region and the region enclosed by receptacle 49 to be evacuated of air prior to the removal of plug 56 from the mouth of passage 50a.

Prior to the start of a series of analyses in chamber 1, plug 56 seals passage 50a until the internal regions of elements 48 and 49 have been evacuated. Plug 56 is then rotated into the open position shown in FIG. 4 and is maintained in that position during the entire period of operation of the spectroscope, or until receptacle 49 becomes filled with spent electrodes.

Each time an electrode is released from clip 2a during the operation of the spectroscope, the electrode falls into funnel 47, where it quickly assumes a flat position adjacent the lower funnel wall and then slides through passage 50a and across region 55, its momentum carrying it through opening 58 and into receptacle 49. Funnel 49 is given a shape and dimensions which will reduce to a minimum the possibility of electrodes becoming jammed therein.

Whenever it is desired to empty receptacle 49, it is only necessary to move plug 56 into its sealing position, to allow air to enter through orifice 48a and to detach receptacle 49 by extracting the ends of stirrup 49a from their respective notches in the end of air lock 48.

Once receptacle 49 has been emptied it is only necessary to replace it, to relatch stirrup 49a, and to evacuate the regions in order to be prepared for another series of test runs.

The device described above thus represents a complete system for handling spectroscope test electrodes with a greater speed, ease and certainty than was known in the prior art. It also permits electrodes to be interchanged without disturbing the vacuum existing in the spectroscope chamber. As an example of the capability of the assembly of the present invention, it has been found possible to exchange electrodes in less than 20 seconds, to carry out one complete analysis run in less than three minutes, and to carry out analyses on 60 sample electrodes in three to four hours, all without unduly hurrying. It may be readily appreciated that such a capability greatly enhances the accuracy of results because the shorter the time elapsed between any two tests, the less the state of the medium within the spectroscope chamber can change, and hence the greater will be the uniformity of the results.

While one form of the present invention has here been shown and described, it should be obvious that many variations and modifications could be made thereto without departing from the spirit thereof. It is therefore intended that the coverage of this invention be limited only by the scope of the appended claims.

What we claim is:

1 In a spectroscope comprising a test chamber, within Which a vacuum is maintained and which has a plurality of openings in its walls, electrode handling means comprising:

(a) electrode gripping means disposed within said chamber for temporarily holding an electrode in the position required for the performance of spectrum analysis;

(b) electrode manipulating means extending through one of said chamber openings and having one end which cooperates with said electrode gripping means for releasing the electrode held therein, said manipulating means comprising stop means which controls the length of an electrode which will protrude from said gripping means; i

(c) electrode inserting means, extending through a second one of said chamber openings, for passing electrodes from the region surrounding said chamber to the interior of said chamber without disturbing the conditions of the vacuum therein;

(d) electrode receptacle means extending through a third one of said chamber openings and having an opening disposed directly below said electrode gripping means; and

(e) a plurality of air tight seals associated with each of said chamber openings for rendering the joints air tight between the said openings and the above recited devices with which they are associated.

2. A device as claimed in claim 1 wherein said electrode gripping means comprises a pair of gripping jaws and a pair of flat springs each of which is connected to a respective one of said jaws so as to urge said jaws towards one another, and said electrode manipulating means comprises: a shaft having a longitudinal axis which is parallel to that of an electrode held in said gripping means; said one end being attached to said shaft and being in the form of a flat blade; said shaft being slidably and rotatably mounted in said chamber opening for inserting said end between said flat springs and separating said aws.

3. In a spectroscope comprising a vacuum chamber for the production of spectrograms, electrode introducing means comprising:

(a) housing means rigidly and impermeably connected to said chamber and having an inner end in communication with the interior of said chamber, an outer end in communication with the environment exterior to said chamber, and an opening in said inner end through which the interior of said chamber communicates with the interior of said housing;

(b) electrode transfer means movably and impermeably mounted in said housing and having an electrode carrying passage which extends therethrough so that each of its ends communicates with a respective one of said ends of said housing means, said transfer means being movable, with respect to said housing means, from a position where said passage is isolated from the interior of said chamber to a position where said passage is in communication therewith; and

(c) closing means cooperating with said electrode transfer means for isolating said passage from the environment surrounding said chamber.

4. A device as recited in claim 3 wherein said housing means is cylindrical and the said opening at its inner end is displaced by the same distance from the longitudinal axis of said cylinder as is said electrode carrying passage.

5. A device as recited in claim 4 wherein said electrode carrying means comprises an extension in the direction towards the interior of said chamber and said electrode carrying passage passes through said extension.

6. A device as recited, in claim 5 wherein the outer cross-section of said extension is inscribable within said opening.

7. A device as recited in claim 3 wherein said closing means has a longitudinal canal which is aligned with said electrode carrying passage when said closing means isolates said passage.

8. A device as recited in claim 7 wherein said closing means further comprises a push member slidably disposed with said canal for connecting said canal and said passage into said chamber.

9. A device as recited in claim 7 wherein said closing means further comprises a connector in communication with said canal for connecting said canal and said passage to a vacuum pump.

10. In a spectroscope comprising a vacuum chamber within which are disposed openable electrode holder means and holder opening means, electrode recovery means comprising:

(a) funnel means disposed within said chamber directly below said holder and having a generally vertical passage for guiding the travel of electrodes released by said holder;

(b) air lock means passing through the wall of said chamber and having a passage therethrough for permitting electrodes to pass out of said chamber, said air lock being connected to said funnel so that the lower end of said funnel passage communicates with one end of said air lock passage; and

(c) detachable receptacle means disposed outside of said chamber and connected to said air look so as to be in communication with the other end of said air lock passage for receiving and retaining electrodes which have passed through said funnel.

11. A device as recited in claim 10 wherein said air lock means comprises movable sealing means for isolating said funnel means from the region in communication with said other end of said air lock passage when said region is at a pressure which differs from that present in said vacuum chamber.

References Cited UNITED STATES PATENTS 4/1962 Bishop et al 2504l.9 9/1965 Hickam 250-413

Claims (1)

1. IN A SPECTROSCOPE COMPRISING A TEST CHAMBER, WITHIN WHICH A VACUUM IS MAINTAINED AND WHICH HAS A PLURALITY OF OPENINGS IN ITS WALLS, ELECTRODE HANDLING MEANS COMPRISING: (A) ELECTRODE GRIPPING MEANS DISPOSED WITHIN SAID CHAMBER FOR TEMPORARILY HOLDING AN ELECTRODE IN THE POSITION REQUIRED FOR THE PERFORMANCE OF SPECTRUM ANALYSIS; (B) ELECTRODE MANIPULATING MEANS EXTENDING THROUGH ONE OF SAID CHAMBER OPENINGS AND HAVING ONE END WHICH COOPERATES WITH SAID ELECTRODE GRIPPING MEANS FOR RELEASING THE ELECTRODE HELD THEREIN, SAID MANIPULATING MEANS COMPRISING STOP MEANS WHICH CONTROLS THE LENGTH OF AN ELECTRODE WHICH WILL PROTRUDE FROM SAID GRIPPING MEANS; (C) ELECTRODE INSERTING MEANS, EXTENDING THROUGH A SECOND ONE OF SAID CHAMBER OPENINGS, FOR PASSING ELECTRODES FROM THE REGION SURROUNDING SAID CHAMBER TO THE INTERIOR OF SAID CHAMBER WITHOUT DISTURBING THE CONDITIONS OF THE VACUUM THEREIN; (D) ELECTRODE RECEPTACLE MEANS EXTENDING THROUGH A THIRD ONE OF SAID CHAMBER OPENINGS AND HAVING AN OPENING DISPOSED DIRECTLY BELOW SAID ELECTRODE GRIPPING MEANS; AND (E) A PLURALITY OF AIR TIGHT SEALS ASSOCIATED WITH EACH OF SAID CHAMBER OPENINGS FOR RENDERING THE JOINTS AIR TIGHT BETWEEN THE SAID OPENINGS AND THE ABOVE RECITED DEVICES WITH WHICH THEY ARE ASSOCIATED.

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