Small volume pipettor

• US 5,958,343 A
• Filed: 12/29/1997
• Issued: 09/28/1999
• Est. Priority Date: 12/29/1997
• Status: Expired due to Fees

• Current Assignee: Thomas W. Astle
• Original Assignee: Thomas W. Astle
• Inventors: Astle, Thomas W.
• Primary Examiner(s): Le, Long V.
• Application Number:
  US08/998,847
• Time in Patent Office: 638 Days
• Field of Search: 422/63, 422/67, 422/68.1, 422/81, 422/100, 422/103, 436/52, 436/180, 436/54, 73/863.1, 73/863.73, 73/864.01, 73/864.16, 73/864.17
• US Class Current: 422/501
• CPC Class Codes: B01L 3/022 Capillary pipettes, i.e. having very small bore B01L3/0224 - B01L3/0237 take precedence
• CPC Class Codes: G01N 35/1065 Multiple transfer devices
• CPC Class Codes: Y10T 436/119163 with aspirator of claimed structure
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

In a preferred embodiment, a small volume pipettor, including: a plurality of pistons; a plurality of liquid delivery needles; motive device to cause one of the pistons to move axially within one of the needles to cause a liquid to be selectively drawn into and discharged from the needle; sealing apparatus disposed around the pistons to effect sealing of upper ends of the needles; assembly apparatus in which the needles and the sealing apparatus are disposed; and apparatus to permit the assembly apparatus to be removed from the pipettor as a one-piece unit. Further provided are novel apparatus to seal upper ends of the needles around the pistons.

Claims

1. A volume pipettor apparatus, comprising:

(a) a plurality of pistons;

(b) a plurality of liquid delivery needles;

(c) motive means to cause one of said plurality of pistons to move axially within one of said plurality of needles to cause a liquid to be selectively drawn into and discharged from said one of said plurality of needles;

(d) sealing means disposed around said pistons to effect sealing of upper ends of said needles;

(e) assembly means in which said needles and said sealing means are disposed;

(f) means to permit said assembly means to be removed from said pipettor apparatus as a one-piece unit;

(g) a generally cylindrical seal surrounding and in contact with said one of said pistons; and

(h) a first O-ring encircling said generally cylindrical seal to serve as a tensioning garter spring to effect a tight seal between said generally cylindrical seal and said one of said pistons.

2. A volume pipettor apparatus, as defined in claim 1, further comprising:

an upper end of said one of said plurality of needles terminating in a V-shaped form, with an upper rim of said V-shaped form engaging a lower surface of said first O-ring, with said first O-ring providing a downward force on said one of said plurality of needles.

3. A volume pipettor apparatus, as defined in claim 2, further comprising:

a second O-ring encircling said V-shaped form, with said second O-ring providing an upward force on said one of said plurality of needles.

4. A volume pipettor apparatus, as defined in claim 3, wherein:

(a) said assembly means includes adjacent upper and lower needle mounting plates having defined therein, respectively, first and second aligned bores;

(b) said first bore has substantially disposed therein said seal and said first O-ring; and

(c) said second bore has substantially disposed therein said V-shaped form and said second O-ring.

5. A volume pipettor apparatus, as defined in claim 1, wherein:

said generally cylindrical seal includes an outwardly extending flange formed at an upper end of said generally cylindrical seal and disposed above said first O-ring.

6. A volume pipettor apparatus, as defined in claim 1, wherein:

(a) said assembly means includes upper and lower needle mounting plates; and

(b) said generally cylindrical seal is formed in a sheet extending between said upper and lower needle mounting plates.

7. A volume pipettor apparatus, as defined in claim 6, wherein:

said generally cylindrical seal has a diameter less than that of said one of said plurality of pistons and has a frusto-conical shape when said one of said plurality of pistons is not inserted through said generally cylindrical seal.

8. A volume pipettor apparatus, as defined in claim 1, wherein:

said means to permit permits said assembly means to be removed from said pipettor apparatus when said pistons have been fully withdrawn from said assembly means.