Pipette dispensing block

• US 6,258,324 B1
• Filed: 03/15/1999
• Issued: 07/10/2001
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: Felix H. Yiu
• Original Assignee: Felix H. Yiu
• Inventors: Yiu, Felix H.
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Gordon, Brian R.
• Application Number:
  US09/268,244
• Time in Patent Office: 848 Days
• Field of Search: 422/100, 422/102, 422/104, 738/633.1, 738/630.2, 738/641.1, 738/641.3, 738/641.6, 738/641.7, 738/641.8
• US Class Current: 422/526
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/02 Burettes; Pipettes
• 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

Abstract

A pipette dispensing block has an improved piston seal and lift plate engagement/disengagement means. In a pipette dispensing block where a piston is used to create a pressure differential to aspirate or extract and dispense or eject fluid material, the maintenance of a vacuum or increased pressure is enhanced by a pair of O-ring seals engaging the piston. A reservoir separates the O-rings and is filled with a low vapor pressure lubricant such as silicone oil or grease. The lubricant is maintained in the reservoir by the O-rings and serves to enhance the vacuum seal while maintaining the O-rings in a pliable and resilient manner. The heads of the pistons are engraved or grooved to leave a circular central pillar surrounded above and below by the piston head and a lower intermediate piston pillar section. The individual pistons are arranged in straight rows so that a slat may slip through opposite pairs of opposing piston pillars thereby entrapping the pistons and preventing them from sliding past the lift plate as the lift plate is lifted upwardly. Shoulders present on the pistons below the lift plate serve to allow the lift plate to push the pistons into the cylindrical chambers of the head block so that a pipette dispenser is provided. The lift plate or portions thereof are then trapped between the slats and the piston shoulders, coupling the pistons to the lift plate. Upward and downward control is thereby established and maintained by the lift plate on the pistons.

Claims

1. A pipette dispensing block, comprising:

a head block, said head block defining a channel, said channel having an upper end, said head block defining a reservoir adjacent said upper channel end;

a piston, said piston slidably travelling through said channel;

a first seal, said first seal adjacent said reservoir and providing a seal between said head block and said piston; and

lubricant, said lubricant held in said reservoir;

whereby

said first seal provides an airtight vacuum seal about said piston adjacent said upper channel end.

2. The pipette dispensing block of claim 1, further comprising:

a second seal, said second seal adjacent said reservoir on a side opposite to that of said first seal such that the reservoir is between said first and second seals.

3. The pipette dispensing block of claim 2, wherein said first and second seals further comprise O-rings.

4. The pipette dispensing block of claim 3, wherein said first and second seals suffer less where and tear from said sliding piston as contact between said first and second seals is lubricated by said lubricant, whereby said vacuum seal is maintained in a better and more enduring manner.

5. The pipette dispensing block of claim 4, wherein said lubricant is a low vapor pressure lubricant, whereby said lubricant does not tend to evaporate into said channel.

6. A pipette dispensing block, comprising:

a head block, said head block defining a channel, said channel having an upper end;

a piston, said piston slidably traveling through said channel;

a first seal, said first seal adjacent said upper channel end and providing a seal between said head block and said piston; and

a second seal, said second seal adjacent said first seal and providing a seal between said head block and said piston;

whereby

said first and second seals provide an airtight vacuum seal about said piston adjacent said upper channel end;

said head block defining a reservoir adjacent said upper channel end, said reservoir between said first and second seals; and

lubricant, said lubricant held in said reservoir;

whereby said first and second seals contain said lubricant in said reservoir.

7. The pipette dispensing block of claim 6, wherein said first and second seals further comprise O-rings.

8. The pipette dispensing block of claim 7, wherein said first and second seals suffer less where and tear from abrasion from said sliding piston as contact between said first and second seals is lubricated by said lubricant, said vacuum seal is maintained in a better and more enduring manner, and said lubricant serves to maintain said first and second seals in a more resilient condition.

9. The pipette dispensing block of claim 8, wherein said lubricant is a low vapor pressure lubricant, whereby said lubricant does not tend to evaporate into said channel.

10. A pipette dispensing block having a lift plate, comprising:

a piston, said piston having a head and defining a head groove adjacent to said head;

a slat, said slat dimensioned in height to engage said piston head by passing through said piston groove;

whereby

said piston is held in place by said piston with respect to the lift plate.

11. The pipette dispensing block having a lift plate of claim 10, wherein said piston further comprises:

a shoulder, said shoulder abutting an underside of the lift plate;

whereby

a lift plate portion is trapped between said slat and said shoulder, locking said piston to the lift plate.

12. The pipette dispensing block having a lift plate of claim 11, further comprising:

said piston being one of several pistons in a first straight row; and

said slat slidably trapped between said first straight row and a second straight row of pistons;

whereby

said pistons of said first and second straight rows are locked to the lift plate by said slat.

13. The pipette dispensing block having a lift plate of claim 12, wherein the lift plate further comprises:

an upper plate, said upper plate defining an upper piston aperture through which said piston passes; and

a lower plate, said lower plate adjacent and below said upper plate, said lower plate defining a lower piston aperture through which said piston passes;

whereby

said piston may be disposed by the lift plate by said upper and lower plates.

14. The pipette dispensing block having a lift plate of claim 13, further comprising:

said lower plate defining a set-in or offset surrounding said piston; and

an O-ring, said O-ring sitting in said offset and engaging said piston;

whereby

said piston is resiliently positioned by said O-ring in alignment with said upper and lower piston apertures.

15. The pipette dispensing block having a lift plate of claim 14, further comprising:

said piston shoulder abutting said upper plate;

whereby

said piston is locked to said upper plate and the lift plate by trapping the upper plate between said piston shoulder and said slat.

16. A pipette dispensing block, comprising:

a head block, said head block defining a channel, said channel having an upper end, said head block defining a reservoir adjacent said upper channel end;

a piston, said piston slidably travelling through said channel, said piston having a head and defining a head groove adjacent to said head, said piston having a shoulder, said shoulder spaced away from said piston head;

a lift plate, said lift plate having an upper plate and a lower plate, said lower plate adjacent and below said upper plate, said upper plate defining an upper piston aperture through which a first portion of said piston passes, said lower plate defining a lower piston aperture through which a second portion of said piston passes, said piston disposed by said lift plate by said upper and lower plates thereof;

a first O-ring seal, said first seal adjacent said channel reservoir and providing a seal between said head block and said piston;

a second O-ring seal, said second seal adjacent said channel reservoir on a side opposite to that of said first seal such that said channel reservoir is between said first and second seals;

a low vapor pressure lubricant, said lubricant tending not to evaporate into said channel, said lubricant held in said reservoir

a slat, said slat dimensioned in height to engage said piston head by passing through said piston groove to hold said piston in place with respect to the lift plate;

said piston shoulder abutting an underside of said lift plate to trap a portion of said lift plate between said piston shoulder and said slat, locking said piston to the lift plate;

said piston being one of several pistons in a straight row, said slat slidably trapped by said straight row so that said pistons of said straight row are releasably locked to said lift plate by said slat;

whereby

said first and second seals provide an airtight vacuum seal about said piston adjacent said upper channel end and said first and second seals suffer less wear and tear from said sliding piston as contact between said first and second seals is lubricated by said lubricant, said lubricant maintaining said vacuum seal in a better and more enduring manner by providing a greater mechanical barrier preserving said airtight vacuum seal, said lubricant lubricating and reducing abrasion between said sliding piston and said first and second seals; and

whereby

said slat provides convenient and easy engagement and disengagement of said piston by said lift plate.

17. The pipette dispensing block of claim 16, further comprising:

said lower plate defining a set-in or offset surrounding said piston; and

an O-ring, said O-ring sitting in said offset and engaging said piston;

whereby

said piston is resiliently positioned by said O-ring in alignment with said upper and lower piston apertures.

18. The pipette dispensing block of claim 17, further comprising:

said piston shoulder abutting said upper plate at a bottom or lower portion thereof;

whereby

said piston is locked to said upper plate and said lift plate by trapping said upper plate between said piston shoulder and said slat.