Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F31/00—Mixers with shaking, oscillating, or vibrating mechanisms
  • B01F31/20—Mixing the contents of independent containers, e.g. test tubes

Definitions

• This invention relates to a laboratory agitator for test tubes or small flasks, which is of improved operation over known agitators.
• Laboratory agitators used at the present time comprise essentially the following parts:
• Parts a, b, c, d are either mounted on a very heavy metal base provided with suckers for its fixing to the working surface, or are suspended in a very heavy metal casing which is also provided with suckers.
• a very heavy metal base or casing is to absorb and damp the vibration, known agitators vibrate in all cases, disturbing the uniform agitation of the liquid contained in the test tube and communicating the vibration both to the operator and to the working surface.
• a laboratory agitator has now been created, and forms the subject matter of the present invention, which is of new design and different from known agitators in each of its parts and overall, and is arranged to ensure effective uniform liquid agitation without vbrating.
• the new agitator has a simple pastics casing which strongly reduces its weight and makes it much more economical to produce.
• the new agitator according to the present invention comprises essentially the following parts:
• the reference numeral 1 indicates the rubber support into which the test tube is inserted under pressure
• 2 indicates the metal insert.
• the reference numeral 3 indicates the connector body, 4 the plastics prong by which that part of the upper edge of the connector lying between two notches extends inwards, 5 the side arm into which the connector extends, and 6 the bore into which a self-tapping screw or similar piece can be inserted; 7 and 8 are two internal cylindrical cavities which together with the central frusto-conical part which connects them together constitute the housing for the eccentric; 10 is a metal plate embedded into the plastics part.
• the reference numeral 11 indicates the central segment of the upper part of the eccentric, which is of frusto-conical cross-section slightly tapering upwards, and is inserted between two segments 12 and 13 of cylindrical cross-sec- tio.
• the electric motor fixed to a base possibly provided with rubber feet for resting on the working surface, is connected to the shaft 24 inserted into the cavity 17 of the eccentric.
• the counter-weight 23 is fitted to the shaft 24 either by screwing or by pressing through the bore 1 6.
• this counter-weight which is one of the inventive aspects of the invention, is to eliminate system vibration and thus obviate one of the main drawbacks of known agitators by a completely new method.
• the mass of the counter-weight is calculated for each apparatus according to the components concerned in the system, i.e. according to the rotating mass, the maximum rotational speed and the value of the eccentricity.
• the determination of the mass capable of totally damping the vibration is to a large extent experimental.
• the counter-weight is fitted on the opposite side of the eccentric axis to the motor axis.
• the plastics connector 3 is mounted on the metal eccentric mounted in this manner on the shaft 24.
• the metal eccentric can rotate in a self-lubricated manner inside the connector, but cannot withdraw from it as it is retained by the plate or washer 22 which engages both with the connector arm and with the projection provided for this purpose on the eccentric, and is fixed by a self-tapping screw 2 1 inserted into the bore 6 of the connector.
• a metal stop pin 20 with a limited facility for vertical sliding is disposed in the cavity 15 of the eccentric. Coaxially to the pin there is disposed a spring 19 emerging a small distance beyond the pin, and on which there rests a metal ball 1 8 housed in the cavity 14, which is of greater diameter than the cavity 15.
• the system comprising the stop, spring and ball ensures resilient movement of the connector along its vertical exis.
• the metal plate 1 0 which prevents deformation and wear of the plastic material is embedded in that part of the connector opposing the metal ball.
• the upper part of the plastics connector is externally of cylindrical shape, whereas internally it comprises a cavity of shape corresponding to that of the metal insert 2, and enabling this letter to the inserted under pressure.
• the upper edge of the connector comprises two notches of approximately 1 cm in depth and such as to allow elastic deformation of the upper edge of the connector.
• the part lying between the notches extends inwards to form two prongs 4 which engage in the conjugate groove provided in the metal insert 2, thus ensuring stable fixing of the test tube holder 1 to the agitator.
• the metal insert is preferably faceted, in general in the form of a hexagonal nut.
• the arm 5 into which the lower part of the plastics connector extends is grooved at its end part in order to receive a seat which allows the guide pin 25 for the arm sliding movement to be inserted.
• the purpose of the arm- pin assembly is to act as a connecting rod for the movement of the eccentric.
• the pin 25 is fixed to the bracket 26 which connects it to the base.
• the end fo the arm 5 also rests on a microswitch 27 which closes under pressure.
• the connector can move vertically in a resilient manner, so that when the test tube exerts pressure on the test tube holder 1, the entire body is lowered and the arm closes the microswitch, thus causing the agitator to operate for the duration of the pressure.
• the microswitch can be disconnected and the agitator can operate by means of a normal manually operated switch independently of the pressure exerted by the test tube.
• the new agitator can be used both for test tubes and for flasks.
• the new agitator has the advantages over known agitators of being absolutely free from vibration, thus ensuring effective uniform agitation without drawbacks for the operator, of being of easier and more economical production in that many metal parts are replaced by plastics parts easily produced by moulding suitable thermoplastic resins, of being very easily disassembled and reassembled by anybody, and of being very easily modified to serve either for test tubes or flasks.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mixers Of The Rotary Stirring Type (AREA)
• Devices For Use In Laboratory Experiments (AREA)
• Mixers With Rotating Receptacles And Mixers With Vibration Mechanisms (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=11166987

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (1)

Citations (5)

• 1982
  • 1982-03-29 IT IT20441/82A patent/IT1151531B/it active
• 1983
  • 1983-02-16 AT AT83101464T patent/ATE20832T1/de not_active IP Right Cessation
  • 1983-02-16 DE DE8383101464T patent/DE3364589D1/de not_active Expired
  • 1983-02-16 EP EP83101464A patent/EP0090165B1/de not_active Expired

Patent Citations (5)

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