U.S. patent number 3,834,240 [Application Number 05/335,367] was granted by the patent office on 1974-09-10 for apparatus for drawing liquids into, and expelling liquids from, a pipette or the like.
This patent grant is currently assigned to Drummond Scientific Company. Invention is credited to James W. Kenney.
United States Patent |
3,834,240 |
Kenney |
September 10, 1974 |
APPARATUS FOR DRAWING LIQUIDS INTO, AND EXPELLING LIQUIDS FROM, A
PIPETTE OR THE LIKE
Abstract
Apparatus for drawing liquids into, and expelling liquids from,
a pipette, including a body member comprising a hand grip portion
and a pipette supporting portion. Duct means are provided in the
body member in communication with one end of the pipette held by
the pipette supporting portion. Valve means are mounted on the hand
grip portion beneath the fingers of the user for selectively
connecting the duct means to a vacuum source or an air pressure
source.
Inventors: |
Kenney; James W. (Philadelphia,
PA) |
Assignee: |
Drummond Scientific Company
(Broomall, PA)
|
Family
ID: |
23311477 |
Appl.
No.: |
05/335,367 |
Filed: |
February 23, 1973 |
Current U.S.
Class: |
73/864.15;
422/922 |
Current CPC
Class: |
B01L
3/021 (20130101); B01L 3/0213 (20130101) |
Current International
Class: |
B01L
3/02 (20060101); B01b 003/02 () |
Field of
Search: |
;73/425.6,425.4P |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Swisher; S. Clement
Attorney, Agent or Firm: Shlesinger, Arkwright, Garvey &
Dinsmore
Claims
What is claimed is:
1. Apparatus for drawing liquids into, and expelling liquid from, a
pipette or the like including:
a. a U-shaped body member,
b. the central portion of said U-shaped body member comprising a
hand grip,
c. the leg portions of said U-shaped body member comprising spaced
support means for the pipette,
d. means for holding the pipette in engagement with said leg
portions,
e. a vacuum source,
f. a pressure source,
g. duct means extending through said body member connecting one end
of the pipette with said vacuum source and pressure source, and
h. a pair of valve members carried by the hand grip in
communication with said duct means,
i. one of said valve members being operative to place one end of
the pipette in communication with said vacuum source,
j. the other of said valve members being operative to place one end
of the pipette in communication with said pressure source.
2. The apparatus of claim 1, wherein:
a. each of said valve members includes a valve bore,
b. a plunger operable within said valve bore,
c. spring means for normally urging said plunger to the raised,
inoperative position, and
d. a groove in the periphery of said plunger,
e. means for preventing communication between said groove and said
duct means when said plunger is in the raised, inoperative
position,
f. said groove establishing communication with said duct means when
said plunger is depressed.
3. The apparatus o claim 2, wherein:
a. the plunger of each of said valve members extends from said hand
grip in underlying relation with two fingers of the hand engaging
said hand grip.
4. The apparatus of claim 3 with the addition of:
a. means for controlling the rate of flow through said duct means
to the pipette when the plunger is depressed.
5. The apparatus of claim 4, wherein:
a. said means for controlling the rate of flow through said duct
means includes a longitudinal groove in the peripheral wall of said
plunger,
b. said groove extending longitudinally of said valve member,
c. the depth of said groove being reduced from top to bottom to
permit a gradual increase in flow through said duct means as the
plunger of said valve member is depressed.
6. Apparatus for drawing liquids into, and expelling liquids from,
a pipette or the like including:
a. a body member of substantially U-shaped configuration,
b. the central prtion of said U-shaped body member comprising a
hand grip,
c. the leg portion of said U-shaped body member comprising spaced
support means for the pipette,
d. a vacuum source,
e. a pressure source,
f. duct means connecting one end of the pipette to said vacuum
source and pressure source, and
g. valve means carried by said hand grip portion and operatively
engaged with said duct means for selectively placing one end of the
pipette in communication with said vacuum source and pressure
source.
7. The apparatus of claim 6, wherein:
a. the terminal of one of said leg portions is transversely arcuate
to complement and receive a portion of the pipette periphery,
and
b. means carried by said one of said leg portions engageable with
the pipette for holding the latter in position.
8. Apparatus for drawing liquids into, and expelling liquids from,
a pipette or the like including:
a. a body member,
b. said body member including a hand grip portion and a pipette
supporting portion,
c. a vacuum source,
d. a pressure source,
e. duct means connecting one end of the pipette to said vacuum
source and pressure source,
f. valve means carried by said hand grip portion and operatively
engaged with said duct means for selectively placing one end of the
pipette in communication with said vacuum source and pressure
source,
g. said valve means including a pair of valve members,
h. each of said valve members comprising a valve bore and a plunger
within the valve bore,
i. the valve bores of said pair of valve members being in
communication with the pipette and said pressure source and vacuum
source respectively.
j. means for normally urging each plunger to a raised inoperative
position in the valve bore,
k. means in the valve bores of said valve members for preventing
communication between the pipette and said pressure source and
vacuum source respectively when said plunger is in the raised,
inoperative position, and
l. means carried by each of said plungers for establishing
communication between the pipette and said pressure source and
vacuum source respectively when the plunger is depressed within the
valve bore.
9. The apparatus of claim 8, wherein:
a. said means for normally urging each plunger to a raised
inoperative position comprises a spring member.
10. The apparatus of claim 9, wherein:
a. said means in the valve bore for preventing communication
between the pipette and said pressure source and vacuum source
respectively comprise sealing members interposed between said
plunger and said body member.
11. The apparatus of claim 8, wherein:
a. said means carried by each of said plungers for establishing
communication between the pipette and said pressure source and
vacuum source respectively comprises a groove in the periphery of
each of said plungers,
b. said groove establishing communication with said duct means when
said plunger is depressed into the valve bore.
12. The apparatus of claim 11, with the addition of:
a. means for controlling the rate of flow through said duct means
to the pipette when the plunger is depressed.
13. The apparatus of claim 12, wherein:
a. said means for controlling the rate of flow through said duct
means includes a longitudinal groove in the periphery of each of
said plungers,
b. the depth of said longitudinal groove being progressively more
shallow from the top to the bottom thereof, whereby a gradual
increase in flow through said duct means is effected as said
plunger is depressed.
14. The apparatus of claim 13, wherein:
a. said plunger extends outwardly from said hand grip in underlying
relation with two fingers of the hand engaging said hand grip.
Description
BACKGROUND AND OBJECT OF THE INVENTION
Various methods and devices have been employed in the past for
drawing liquid samples into pipettes including mouth pipetting, the
use of rubber sucker tubes, and a variety of hand-operated
syringe-type devices. All of these methods have been found to have
disadvantages in actual use. The problem with mouth pipetting and
the use of rubber sucker tubes is that, on occasions, when it is
desired to pipette dangerous or noixious materials, the fumes are
inhaled, with resultant harmful effects. The hand operated syringes
although avoiding the disadvantages of mouth pipetting, are
tiresome to operate when pipetting repetitive liquid samples.
More recently, mechanical devices have been developed for drawing
liquid samples into pipettes as illustrated by U.S. Pat. No.
3,310,002 granted Mar. 21, 1967, and U.S. Pat. No. 3,463,013
granted on Aug. 26, 1969. While these mechanical devices overcome
the objections of the above methods and devices for pipetting
fluids, the structure thereof is cumbersome to operate, thereby
reducing the facility with which liquid samples may be drawn into
and expelled from, the pipette and also causing fatigue after
repeated use.
It is therefore an object of this invention to provide apparatus
for drawing liquids into, and expelling liquids from, a pipette,
which includes a hand-held body member to which a pipette is
attached, the body member being provided with valves underlying the
fingers when in the position of use and selectively operable to
apply either a vacuum or an air pressure to one end of the pipette
for drawing the liquid into, and expelling the liquids from, the
apparatus.
Another object is to provide apparatus of the character described
which is adapted to be readily held in the palm of one hand with
the fingers easily and naturally movable to actuate valves
strategically positioned on the hand grip portion thereof.
A further object is to provide apparatus of the character described
which is of simple construction, and in which a pipette may be
quickly attached thereto for expeditiously filling and emptying
pipetes without fatigue.
A still further object is to provide a valve operated apparatus of
the character described wherein said valves are constructed to
allow varying degrees of communication between the pipette and the
vacuum or air pressure source, to permit filling and emptying of
the pipette at the desired rate.
Other objects will be manifest from the following description of
the preferred form of this invention, taken in connection with the
appended drawings.
DESCRIPTION OF FIGURES OF THE DRAWINGS
FIG. 1 is a side elevational view of the apparatus of the present
invention, illustrating its use;
FIG. 2 is an enlarged sectional view taken along the line 2--2 of
FIG. 1, looking in the direction of the arrows;
FIG. 3 is a sectional view taken along the line 3--3 of FIG. 1,
looking in the direction of the arrows;
FIG. 4 is a sectional view taken along the line 4--4 of FIG. 1,
looking in the direction of the arrows;
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 1,
looking in the direction of the arrows;
FIG. 6 is an enlarged sectional view of the valve members forming a
part of the present invention, showing one valve in inoperative
position, and the other valve in operative position, and
FIG. 7 is a view similar to FIG. 6, but showing the valve members
in reverse operational position.
DESCRIPTION OF THE INVENTION
The apparatus of the present invention generally includes a body
member 16 for holding a standard pipette 18 which body member is
connected by a pressure line 20 to a source of air pressure 22 and
by a vacuum line 24 to a vacuum source 26. As indicated in FIG. 1,
these lines may be coaxially positioned with respect to each
other.
Body member 16 is preferably of U-shape configuration, the central
portion of which provides a hand grip 28 and the leg portions of
each, designated 30 and 32, provide spaced means for supporting and
holding pipette 18.
The outer terminal of leg portion 32 is provided with an arcuate
recess forming a saddle 34 of generally semi-circular shape in
cross-section for receiving an intermediate portion of pipette 18.
A continuous spring member 36 extends through a transverse bore 38
in member 32, which spring extends across saddle 34 for holding the
pipette in position during filling and emptying thereof.
When pipette 18 is in the position show in FIG. 1, the upper end
thereof engages a grommet seal 42 secured to leg portion 30 in
facing relation to saddle 34. Seal 42 has a central aperture 44
which communicates with a duct 46 in leg portion 30. Duct 46
communicates with a duct 48 extending longitudinally of leg portion
30, which duct in turn communicates with a duct 50 extending
partially through, and longitudinally of, hand grip 28. Duct 50
communicates with the lower portion of a valve bore 52, which bore
is in communication with a like spaced valve bore 52' by means of a
connecting duct 51. Valve bores 52 and 52' house a pair of like
valve assemblies designated 54 and 54' respectively.
As shown in FIGS. 1, 6 and 7, valve assemblies 54 and 54' are of
like construction and include sliding valves 56, 56' which are in
sliding engagement with the walls forming reduced sections of the
upper portion of bores 52 and 52', which valves have actuating
buttons 58, 58' secured to the upper terminals thereof. Beneath
valves 56, 56' are convolute springs 60, 60' mounted in the valve
bores, the upper ends of which springs engage the lower terminals
of valves 56, 56', and the lower ends of which springs engage
combination caps and spacers 62, 62', which are in threaded
engagement with the lower end wall portions of the bores. Caps and
spacers 62, 62' include integrally formed cylindrical portions 64,
64' in surrounding relationship with convolute springs 60, 60'.
Under urging of springs 60, 60', valves 56, 56' are normally urged
to the inoperative position shown in FIG. 1. Pairs of spaced O-ring
seals including upper seals 66, 66' and lower seals 68, 68' are in
peripheral engagement with the lower ends of valves 56, 56' and
fixed to hand grip portion 28 on both sides of ducts 50 and 51, the
seals lying proximate the lower ends of valves 56, 56' when the
latter are in the inoperative position of FIG. 1. Valves 56, 56'
are provided with longitudinally extending grooves 70, 70' located
in the peripheral walls of the valves, which grooves lie above
sealing rings 66, 66' out of communication with dust 50 when the
valves are in the inoperative position. As also shown in FIGS. 6
and 7 when either valve is in the operative position, longitudinal
grooves 70 or 70' are in communication with duct 50 or duct 51.
It is a salient feature of the present invention to form grooves
70, 70' of non-uniform cross-sectional area throughout their
length. This is effected by providing tapered inner groove walls
72, 72' so that the groove is progressively more shallow from the
top to the bottom thereof. In this way, controlled communication
with pipette 18 is effected, thereby regulating the rate of filling
and/or emptying the pipette.
Hand grip 28 is further provided with a pair of air ducts 74 and 76
which extend through a fitting 78 threadedly engaged with body
member 16. Ducts 74 and 76 pass through coaxial tubular extensions
80 and 82 carried by fitting 78, said tubular extensions being
engaged with vacuum line 24 and air pressure line 20 respectively.
Duct 74 is in communication with valve assembly bore 52 and duct 76
is in communication with valve assembly bore 52'.
Therefore, as shown in FIG. 6, when valve 56 is depressed by
operation of button 58, the movement of groove 70 into
communication with duct 50, also effectively establishes
communication between vacuum source 26 and pipette 18 through duct
74, valve bore 52, groove 70, ducts 50, 48 and 46, and bore 44 of
grommet seal 42. In like manner, when button 58' is depressed as
shown in FIG. 7, communication is effected between air pressure
source 22 and pipette 18 through duct 76, valve bore 52'. groove
70', connecting duct 51, valve bore 54, ducts 50, 48 and 46, and
bore 44 of grommet seal 42.
Valves 56, 56' are further provided with central longitudinal bores
84, 84' which, when the valves are in the inoperative position
shown in FIG. 1, extend from a point above hand grip portion 28 to
a point in alignment with duct 72. Bores 84, 84' are provided with
upper vents 86, 86' and lower vents 88, 88' and establish
communication between duct 74 and 76 and the atmosphere, while the
valves are in the inoperative position shown in FIGS. 1 and 6. When
valves 56, 56' are depressed, vents 86, 86' are no longer open to
the atmosphere and communication between the pressure or vacuum
sources and the atmosphere is closed.
OPERATION
In use of the apparatus of the present invention, pipette 18 into
which a liquid sample is drawn is placed in saddle 34 in the
position shown in FIG. 1, with the upper end in contiguous relation
with grommet seal 42 and the bore thereof aligned with seal
aperture 44.
When it is desired to fill the pipette to any desired extent, body
member 16 is grasped in one hand in the manner illustrated in FIG.
1 so that the index finger and middle finger overlie actuating
button 58 and 58' respectively. In order to draw the liquid into
the pipette, button 58 is depressed to place the vacuum source 26
in direct communication with the upper end of pipette 22, resulting
in a suction of the liquid into the pipette. The rate at which the
liquid is drawn into the pipette is controlled by extent to which
valve 54 is depressed. When the desired amount of liquid has been
drawn into the pipette, button 58 is released by the finger, and
the valve automatically returns to the inoperative position under
urging of spring 60.
In dispensing the liquid from the pipette, a similar procedure is
followed except that actuating button 58' is depressed thereby
placing air pressure source 22 in direct communication with the
upper end of pipette 18 to expel fluid from the pipette in a well
known manner.
With the apparatus of the present invention, liquids may be
repeatedly drawn into and expelled from a pipette, and the pipette
is readily positioned in a very expeditious manner. Additionally,
the structural arrangement of the present apparatus is comfortable
to hold and the valves thereof are strategically positioned so that
actuation thereof is readily accomplished by an easy and natural
finger movement, so that no fatigue or other strain is experienced
by the user even if used over a long period of time.
While there has been herein shown and described the presently
preferred forms of this invention, it is to be understood that such
has been done for purposes of illustration only, and that various
changes may be made therein within the scope of the appended
claims.
* * * * *