DE1532692A1 - Door mechanism for a vacuum centrifuge - Google Patents

Description

Patent attorney

MUNICH-SOLLN

Franz-Hals-Strasse 21

Telephone 796213

BM 1960

Munich, November 3, 1966 Dr.H./Dr.S./Ar.

Beckman Instruments, Ine, 2500 Harbor Boulevard Fullerton, California, U.S.A.

Door mechanism for a vacuum centrifuge

Priority: USA; 5 November 1965; US Serial No. 506 492.

The invention relates generally to centrifugation apparatus with a rotor running at high speed, which is arranged within a vacuum chamber and specifically to a door mechanism for the vacuum chamber.

High speed centrifuges, sometimes referred to as "ultracentrifuges", can have rotor speeds on the order of 50,000 revolutions use per minute and even more. To get speeds of this size and aerodynamic warming up to reduce it to a minimum, it is important that the rotor

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is mounted in a chamber that can be evacuated « Since the chamber is a permanent part of the centrifuge structure, it is necessary to make the interior of the chamber accessible to make in order to insert the rotor or to be able to take it out again. The chamber is therefore typical provided with an access hole in the top plate covering the chamber. A horizontally moving door that either Can be opened and closed automatically or by hand, is used to cover the access hole during of the centrifuge operation.

To create an airtight seal during centrifugation To create a sealing element, typically in the shape of an O-shaped ring, in the upper surface the top plate mounted around the chamber access hole. As a result of the drop in pressure difference during evacuation the chamber, the door rests against the sealing element and forms an excellent seal,

In the known door mechanisms, the sealing element significantly worn as a result of rubbing, when the door is opened or closed. This occurs with the horizontal movement of the door while it is in contact is with the sealing element. One object of the invention is hence in creating a door mechanism in which

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wear of the sealing element by. Abrasion or Nibbling off is kept to a minimum.

If a centrifugation of a zonal or continuous Stromes is made, the rotor used requires an assembly consisting of an upper bearing and seal corresponding inlet and outlet lines for the iluid-r This unit can be detachably mounted in the vacuum chamber door, as published in US Pat. No. 3,168,4-4 on February 2, 19651 of the applicant. To ensure correct alignment between the drive spindle for the rotor and the unit from the upper bearing and seal To ensure that the door must be precisely located in its closed position. It is therefore also a The aim of the invention to provide a door mechanism, the exact arrangement of the door with respect to the drive spindle of the Rotor ensures.

The invention thus relates to a centrifuge with a vacuum chamber, which serves as a housing for a rotor, which is driven from below by a spindle, with a door mechanism for the vacuum chamber one above the top the top plate attached to the vacuum chamber and this top plate has an access hole from the top plate worn sealing means are disposed around the access hole and a door is provided which is sealingly attached to the

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Can attack sealing means and by a transport mechanism between closed and open positions to cover and uncover the access hole is movable. The invention is characterized in that the transport mechanism is horizontally movable and one Cam means for holding and vertically sliding the door during initial horizontal movement of the transport mechanism when opening the door and during horizontal movement of the transport mechanism at the end upon closing the door and further means for holding the door in place during its vertical Movement and a locking device engaging the door for holding the door during its horizontal movement.

The invention is described below with reference to schematic drawings explained in more detail using several exemplary embodiments, in which further objects, features and advantages of the invention become clear It show:

Fig. 1 in an exploded perspective view, partially cut, a door mechanism according to one embodiment of the invention;

Figure 2 is a top plan view of the door mechanism of Figure 1 in place in a centrifuge device;

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3 shows a cross section seen from the end face the device of Figure 2 along the plane 3-3;

FIGS. 4-a-4d are schematic side views of the door mechanism, in which different operating levels are shown are; and

FIGS. 5a-5c are schematic end views, partially in section, in which the operating steps of the locking mechanism become clear according to the invention »

The door mechanism according to FIGS. 1 to 3 generally has' a substantially square door 10, side spacer blocks 12 and 14-, a rear spacer block 16 and Door transport elements 18 and 20. How best to get into the 2 and 3 can be seen, the door mechanism is carried by a substantially square top plate 22 which is attached to the top of a generally cylindrical vacuum chamber 24 is mounted, which is defined by an outer wall 26 and a bottom, plate 28 is formed. The top plate 22 is provided with an access hole 30 provided for the chamber large enough to accommodate a bä-lively of the various in question To be able to insert and remove rotors that can be used in the centrifuge. An annular groove 32, which is formed in the upper surface of the top plate 22 directly on the circumference of the hole 30 is dimensioned so

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that they have a resilient O-shaped ring 34 can accommodate, which serves as a seal for the chamber 24 when the door 10 is in its closed position. The O-shaped ring 34 can be made of any suitable synthetic Be made of rubber. In its expanded form, the compliant O-ring 34 extends above the upper surface of the top plate 22, as can be seen in FIG. When the door 10 is in its closed position and the chamber 24 is evacuated, the O-ring 34 is compressed by the door 10 and fills completely the groove 32.

Appropriate precautions are taken to ensure a good vacuum seal between the top plate 22 and the top edge the outer wall 26 to create. In this sense, an annular recess 36 is provided, which is elastic to a compliant O-ring 38 is adapted, made of suitable Material, such as synthetic rubber, can be made. Normally, the O-ring 38 is compressed somewhat, whereby an effective vacuum seal is maintained.

Injury or damage in the event of a rotor failure To prevent operation during operation, a heavy safety ring 40 is arranged within the outer wall 26. Inside the safety ring 40 is a lightweight container

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or an Au ski e idling 42 is provided which has a rotor 44 surrounds. The rotor 44 is supported and driven by a spindle 46, which is connected to a motor-gear unit (not shown) connected is. The rotor 44 sketched in the drawings is of the fixed angle type as he is normally used in preparative centrifuges. There can also be rotors for zonal or continuous flow centrifugation can be used in the apparatus shown. Since the latter rotors have an upper bearing and Need a sealing unit that serves as a housing for suitable inlet and outlet lines for a fluid, a mounting device is provided in the door 10, in order to be able to accommodate such an aggregate. Suitable mounting devices can take the form of a central arranged opening 48 have in the door 10 with a quick-release thread or other fastening means is provided. Reference can be made to U.S. Patent No. 3,168,474 mentioned above. If the opening 48 does not is needed, it is provided by a removable disc-shaped stake 50 as shown in FIGS. 2 and closed. It goes without saying that when using an upper storage and sealing unit, the alignment between this unit and the drive spindle 38 must be strictly observed. The following is a facility for arranging the door 10 is described in detail, in which the exact positional arrangement can be achieved.

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The spacer blocks 12, 14 and 16 support a relative heavy, generally square cover plate 52 with an access opening 54- for the chamber which is essentially is coaxial with hole 30 in plate 22. (For the sake of clarity, the cover plate 52 is shown in the perspective view of Figo 1 omitted). The unit consisting of a cover plate 52, the spacer blocks 12, 14 and 16, the top plate 22, the outer wall portion 26 and the bottom plate 28 are securely attached to one another, as in FIGS Fig. 2 and 3 is shown by means of eight clamping bolts 56, which are designed to withstand extremely high tension loads. The whole yakuum chamber unit, which will be described immediately below is supported by a frame 58 shown in dashed lines is shown in Figs.

The door 10 is moved between the open and closed positions by means of transport elements 18 and 20, which are attached to both Door sides are provided. The transport elements 18 and 20 can usually be constructed from commercially available racks that are essentially square in cross-section to have. The racks 18 and 20 are arranged between the door 10 and the spacer blocks 12 and 14, respectively, and a suitable one free space is allowed so that the racks can slide freely.

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1532892

On the upper surface of each rack 18 and 20 is a Pair of cam surfaces or ramps 60 formed on a pair of support means for the door during of the door operation. The means of support for the door can be in the form of pins 62 which laterally protrude from door 10. The upper ends of the Kampen 60 connect to horizontal seats 64, which serve to the support pins 62 during the horizontal Door 10 transports. The rearmost end of the racks 18 and 20 is fork-shaped and receives wheels 66 rotatably supported by shafts 68. Plastic-tyred ball bearings can be more convenient than that Wheels 66 are used. The wheels 66 have a diameter that is slightly narrower than the height of the spacer blocks 12, 14 and 16 so there is no dragging or rolling resistance comes into play during the spin.

A guide device for the door 10, which is effective during its vertical travel and the door relative to Correctly arranging the drive spindle for the rotor is described below. The door 10 is with a pair of Holes 70 are provided which are diagonally opposite to one another are arranged and can accommodate a pair of rounded or beveled studs 72, which according to protrude from the top of the top surface of the top plate 22.

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Alignment between the studs 72 and the holes 70 as the door descends towards it the closed position is ensured by the rounded or beveled section of the studs, and the lower, straight section of the studs provides proper ultimate door orientation.

Means are provided to lock the rack 18 and the door 10 together so that these members during the horizontal door movement move together with each other. The locking means according to the preferred embodiment of the invention can, as can best be seen in FIGS. 2 and 5a, the shape of a Pin 74 · have a head 76 which is in a Toothed rack 18 provided cylindrical recess 78 will be carried. A spring 80 biases the head pin outward, i.e., towards the spacer 12. A cam surface 82 having a straight section 84 and an inclined section 86 is in spacer block 12 the side adjacent to the rack 18 is formed. The locking pin 74 · is engaged by the cam surface 82 in operated in a manner to be described so that the pin enters a vertical slot 88 formed in the door 10 to the rack 18 adjacent. Side is formed.

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The racks 18 and 20 are driven by a pair of gears 90 in the same mode, which is on a rotatable Shaft 94 is mounted in stationary, not shown and support arms carried by the frame 58 are rotatably supported. The gears 90 mesh with the toothed one lower surface of racks 18 and 20. Any suitable means, be it automatic or manual, can be provided to drive the gears. According to the preferred embodiment of the invention a manually operated chain drive is provided which generally includes a drive sprocket 96 rotatable on a not shown and attached to the frame 58 support part is mounted, an eye at one end of the shaft 94 · Brought drive sprocket 98 and an endless chain 100 having, which the sprockets 96 and 98 with each other connects. The chain drive can be operated by turning a knob 102 attached to a shaft 104 which is connected to the drive sprocket 96.

The following is the operating cycle of the door from the

described closed position to open position with reference to FIGS. 4a-4d and 5a-5c. Turning the Clockwise knob 102 leads to a corresponding one Rotation of drive sprocket 98 causing racks 18 and 20 to move horizontally forward or begin in the direction of the open position.

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Since there is a slight free space between the pins 62 and the lowermost end of the ramps 60 is provided requires a small initial movement of racks 18 and 20 before ramps 60 engage pins 62 (Fig. 4a). If the racks continue to move the ramps 60 acting on the pins 62 push the door 10 upwards. The door 10 is now through the Racks 18 and 20 carried, which in turn are supported solely by the wheels 66 and the gears 90. Finally, as shown in Fig. 4b, a point is reached at which the lower surface of the door 10 is straight from the upper ends of the Standing pin 72 comes free. At this point, the pins 62 have not quite reached the top of the ramps 60. During the small vertical displacement of the door that remains until the pins 62 reach the seats 64, will a horizontal movement of the door is prevented by a holding device which holds one on the rear edge of the door 10 attached spring clip 106 and an adjustable stand 108 on which the clip 106 releasably engages. The stand 108 is attached to the top plate 22 by means of a screw bolt 110 which is fixed in a longitudinal slot 112 is held and protrudes upwards from it. A nut 114 can be used to secure the bolt 110 to hold in its place. It should be noted that the spring clip 106 and the stand 108 are shaped so that between them relative vertical movement is allowed if they

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are engaged. As can best be seen in FIG can, the stand 108 is shaped so that relative to the clip 106, the engagement resistance is less than the resistance associated with disengagement is. This is accomplished by making the front end of the stand 108 with a stepped or gradual Conicity 116 and the rear end with a steep conicity 118 is provided. To help make a Rearward displacement of the stand 108 as a result of the door 10 being hit is one from the rear supporting screw 120 is provided. The screw 120 is expediently through the rear spacer 16 carried, which is provided with a corresponding screw hole 122. One attached to the end of screw 120 Knob 124 protruding rearwardly from spacer 16 is used to turn the screw.

When the door mechanism is in the positions shown in FIGS. 4a and 4b, the locking device assumes the positions shown in FIGS. 5a and 5b, respectively. It will be appreciated that the pin 7 ¹ * · performs a motion along the straight portion 84 of cam surface 82 during the initial movement of the door 10 degrees. Further horizontal movement of the racks 18 and 20 causes the door pins 62 to climb onto the horizontal seats 64 and the pin heads 76 ευα the inclined section

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-I486 engage the cam surface 82 and thereby drive the pin 74 into the slot 88, the latter both elements are then aligned with each other (Fig. 4c and 5c). This action locks; the racks 18 and 20 on door 10 in such a way that further horizontal movement of the racks results in that the clip 106 and the stand 108 disengage as shown in Figure 4d. When the door 10 on the seats 64 and the locking pin? 4 in the slot 88, a horizontal movement begins in the direction of the Open position. During the initial horizontal hike of the door 10, the wheels 66 are in contact with the top of the top plate 22. When the center of gravity of the Door mechanism reached beyond the shaft 94 for the gearwheel, the mechanism rotates a little clockwise about shaft 94 causing the wheels to turn 66 lift off the top plate 22 and come into contact with the bottom surface of the top plate 52. The operator then rotates the knob 102 continuously until the door 10 is in the fully open position and thereby makes the interior of the vacuum chamber 24 accessible.

To close the door, run the one just described Operation is reversed, with the operator moving button 102 counterclockwise. Reached the door the end of their backward path if the

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Clip 106 engages the stand 108. The position of the stand 108 is adjusted "before the machine is operated is taken so that when the door reaches the end of its horizontal travel path in the closing direction, the orientation holes 70 in the door 10 are aligned with the studs 72. The final movement of the racks 18 and 20 then causes the spigot head 76 to be in contact is moved with the cam surface 82, thereby disengaging the pin 74 and slot 88 and in addition, the door 10 descends vertically downward until contact is made with the sealing O-inlet 34. In the end position of the racks, the door 10 is supported solely by the sealing O-ring 34. Between Pins 62 and the lowest point on the ramps 60 is provided enough free space so that during evacuation of the chamber and coming down the door 10 towards the top plate 22 the pins 62 are not on the ramps " Reason, come ". The pressure difference on the door as a result of the Chamber evacuation brings the door into metal-to-metal contact with the top of the top plate 22, causing the O-shaped ring to deform within the confines of the pit 32 and compressed to effect a substantially airtight seal. You can see that the Door movement has no horizontal component when the bottom surface of the door comes into contact with the o-ring, and so that there is no erasing, leading to wear and tear on the O-ring.

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Other advantages reside in the structural features of the invention. For example, the simplicity of construction ensures for simplicity of construction and adjustment of the door mechanism. Since then the door is only rests on the racks 18 and 20, their removal for repair work or in the case of replacement is a easy thing.

Claims

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Claims (4)

EM 1960 patent claims 1. Door mechanism for a centrifuge with a vacuum chamber, which serves as a housing for a rotor which is driven from below by a spindle, the door mechanism for the vacuum chamber has a top plate fixed over the top of the vacuum chamber and this top plate has an access hole carried by the top plate Sealing means are arranged around the access hole and a door is provided which can sealingly engage the sealing means and by a transport mechanism is movable between closed and open positions for covering and rediscovering the access hole, thereby characterized in that the transport mechanism (18, 20) is horizontally movable and cam means (60, 62, 64-) holds the door (10) and holds it horizontally Movement of the transport mechanism (18, 20) initially when opening the door and at the end when closing the door Door slides vertically, and that further means (106, 108) for holding the door during its vertical Movement and a locking device (82) engaging the door for holding the door during its horizontal Movement are provided. - 18 009820/0016 2. Door mechanism according to claim 1, characterized in that there is also a device (70, 72) for vertically guiding the door (10) and aligning this door in the closed position with respect to the ßotorspindel (46) is provided. 3. Door mechanism according to claim 1 or 2, characterized gekennz eichnet that the door (10) each a pair from both sides of the door (10) to the outside has protruding pins (62) and the transport mechanism on both sides of the door each with a transport element a toothed rack (18, 20) with a toothed underside and on the top of the toothed racks as a cam a pair of ramps (60) is formed, which is adjoined to the rear by a horizontal surface (64), which serves as a seat for the pins (62) during the horizontal movement of the door. 4. Door mechanism according to one of the preceding claims, characterized in that the Locking device has a pin (74) which is mounted on the transport mechanism (18, 20) and from one side the door (10) can be moved back and forth and is under spring tension (80), which is directed away from this door side is, wherein the door (10) has a receiving slot (88) 009820/0018 for the locking pin (74 ·) and the transport mechanism a cam surface (86) "has the pin (74-)" when the transport mechanism moves horizontally drives towards the open position in the slot (88). 009820/0016