Pipet washer

A self-contained pipet washer and dryer which utilizes a container assembly within which is located a quantity of the pipets that are to be washed and dryed. An acid storage tank is included which includes a volume of acid which is to supply acid into the container to soak the pipets for a period of time. Tap water is to be supplied into the container to initially rinse the pipets after the acid soaking. A second source of rinsing solution, in the form of deionized water, is provided to function as a final rinse for the pipets. Heated air is to then be blown across the pipets to dry the pipets.

BACKGROUND OF THE INVENTION 
The field of this invention relates to a washing and drying apparatus for 
utensils, and more specifically to an automatic washing and drying 
apparatus for pipets. 
Pipets are in common use in medical laboratories and other types of 
laboratories. One way in which a pipet is used is in the performing of 
blood tests. The pipet is used to remove precise volumetric amounts from a 
reagent or sample to then be transferred to a vial which contains certain 
substances for performing certain types of tests. Once the pipet has been 
used, it is normally set aside to be washer prior to its next usage. 
Most pipets are constructed of glass. In order to prevent the possibility 
of contamination both to the user and the test reagents, the washing 
procedure for the pipets is quite extensive. The pipets are usually first 
soaked in a mild acid solution for a certain period of time, such as 
thirty minutes to one hour. A desirable type of acid solution would be 
sulfuric acid dichromate. 
The normal procedure for washing pipets is to accumulate a substantial 
number (a days supply) and manually place the pipets within a container 
full of the acid solution. After the pipets have soaked for a reasonable 
period of time, the acid solution is drained and then the pipets are 
washed several times in tap water and then finally rinsed in deionized 
water. The pipets are then removed from the container and placed in an 
area to dry. It is not at all uncommon for the entire washing and drying 
procedure to take a period of several hours. In other words, within the 
laboratory, it is required that a single individual take three to four 
hours of time to properly wash and dry the pipets that have been used 
during the previous day. 
There has long been a need to design an automatic washing and drying 
apparatus for pipets which would eliminate the hazardous and time 
consuming chore of washing and drying pipets. It is essential that pipets 
are scrupulously clean due to the possible health hazards associated with 
the testing of body fluids and common laboratory reagents. 
SUMMARY OF THE INVENTION 
The structure of this invention relates to a self-contained unit within 
which is located a washing and drying chamber. This washing and drying 
chamber has a removable basket. The pipets to be washed and dryed are to 
be located within the basket. The chamber is capable of being filled with 
an acid solution which is located within a storage reservoir mounted 
within the self-contained unit. After the pipets have been soaked in the 
acid solution for the desired period of time, the acid solution is drained 
from the chamber back into the storage reservoir. The chamber is then 
filled and drained a plurality of times with conventional tap water. This 
functions as the beginning of the rinse cycle for the pipets. After this 
initial rinse cycle, the pipets are sprayed a plurality of times with a 
measured quantity of deionized water. Normally this deionized water is 
heated. After this final rinse cycle, the pipets are dried by being 
subjected to a continuous blast of heated air. The air is supplied from an 
air compressor. The air compressor also functions to pump the acid into 
the chamber as well as pumping of the deionized water into the chamber. A 
novel valve is utilized in conjunction with conduits through which the 
acid is moved to and from the chamber. This valve is deemed to be 
substantially acid resistant. The valve includes a valve chamber within 
which is located a valve spool. The valve spool is movable in between an 
open position permitting the acid to flow through the chamber and a closed 
position preventing the flow of acid through the chamber. The valve spool 
comprises a ceramic magnet which has been exteriorly coated with a 
plastic. A desirable type of plastic would be what is commonly sold under 
the trade name of TEFLON. The valve spool is moved by activation of an 
electromagnet which has been mounted in conjunction with the valve. 
The primary objective of this invention is to construct a pipet washing and 
drying apparatus which can be used in laboratories to automatically wash 
and dry a quantity of pipets, leaving the pipets totally free of foreign 
material which could contaminate and produce false results in the 
preforming of certain tests.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT 
Referring particularly to the drawings, there is shown the pipet washer and 
dryer 20 of this invention which is shown mounted contained within a 
housing 22. The housing 22 is basically box-like in configuration and 
includes an enlarged internal compartment 24. Within the front portion of 
the housing 22 there is located a removable front wall 26. The removable 
front wall 26 is in order to gain access into the internal compartment 24 
for reasons for maintenance and repair. 
Also formed within the front wall of the housing 20 and located above the 
removable wall 26 is a panel 28. Within the panel 28 are located a series 
of buttons and indicator lights which are to be connected to an electrical 
regulator (not shown). Indicator light 30 is to indicate if the deionized 
water 32 within the tank 34 is at the full level. This indication is given 
through flow switch mechanism 36 mounted within the tank 34. Indicator 
light 38 is to indicate if the water level of the deionized water 32 is at 
a low level requiring the operator to add additional deionizing water into 
the tank 34 through the inlet 40. The panel 28 and removable wall 26 are 
hinged together by hinge 25. 
If the operator manually pushes button 42, the acid solution 44 located 
within the acid tank 46 is to be moved through conduit 50 to fill the 
soaker container 52. The acid is moved through the conduit 50 into the 
soaker container 52 by means of air pressure being applied to the surface 
of the acid solution 44. This air pressure is supplied by electrically 
activating air compressor 53. 
Located within the conduit 50 is a check valve 54 which permits liquid to 
be conducted to the conduit 50 only in the direction into the soaker 
container 52. During the pumping of the acid solution 44 from the tank 46, 
the atmospheric vent 56 of the tank 46 is closed by means of valve 58. The 
air pressure from the air compressor 53 is permitted to be conducted into 
the acid tank 46 when the valve 60 opens. 
The soaker container 52 is connected to an acid solution drain conduit 62. 
The acid drain conduit 62 is closed by a valve 64 during the supplying of 
the acid solution 44 into the soaker container 52. It can be seen by the 
drawings that when the acid solution 44 is drained from the soaker 
container 52, that it is conducted back into the acid storage tank 46. 
This is so that the acid solution 44 can be used a plurality of times and 
does not need to be replaced every time. When it is desired to replace the 
acid solution 44, such is to be drained through manually operated and 
vented drain valve 60. New acid solution 44 is to be conducted into the 
tank 46 by means of a conduit 68 and check valve. Pump 69 is actuated by 
switch 39 on panel 28. Switch 39 also opens atmospheric vent 56 by means 
of valve 58. When storage full light 72 is activated, switch 39 is 
automatically deactivated as is the valve 58 closing atmospheric vent 56. 
Also located within the acid storage tank 46 is a float switch mechanism 
70. This switch mechanism controls indicator lights 72 and 74 to indicate 
to the operator whether the amount of acid solution 44 is at a high level 
or a low level. The indicator lights 72 and 74 are located on the panel 
28. 
If for any reason it is desired to drain the deionized water 32 from the 
tank 34, there is provided a drain conduit 76 and a drain valve 78. Drain 
valve 78 is mounted within the removable front wall 26. 
Upon activation of the button 80, the valve 64 is opened and the acid 
solution 44 within the tank 52 is emptied into the acid storage tank 46. 
After all the solution 44 has been emptied back into the tank 46, the 
valve 64 closes and tap water is then supplied from conduit 82 by opening 
of valve 84. Tap water is permitted to completely fill the soaker 
container 52 and upon reaching the full level, the float indicator 
mechanism 86 closes the valve 84 not permitting any more tap water to 
enter within the soaker container 52. 
After a period of time, the regulator (not shown) will automatically open 
valve 88 to permit the tap water to be drained through the vented drain 
conduit 90 and to be discharged by any desirable manner. 
The button 92, when activated, activates the pump 68, which is to supply 
the acid solution 44 into the tank 46 from the source (not shown). The 
operator is to activate the button 92 when the indicator light 74 shows 
that the level of the acid solution 44 is low. The acid solution is to be 
supplied through a valve 94 into the tank 46. 
Also mounted within the panel 28 is an indicator light 96. The light 96 
functions to indicate that the drying cycle is activated. 
Also mounted within the panel 28 is an on-off switch 98 which is for the 
purpose of either activating or deactivating the entire pipet washer and 
dryer 20 of this invention. The soaker container 52 has mounted therein a 
basket 100. The basket 100 will normally be constructed of a rigid 
material such as plastic or metal. Within the basket 100 there is to be 
placed a quantity of elongated pipets 102. Smaller, shortened pipets 104 
can be located within small compartment 106 of basket 100. 
The basket 100 can be removed from the soaker container 52 through access 
opening 108. The access opening 108 is normally closed by means of a lid 
100. The lid 110 is normally closed onto the housing 22 by means of 
latches 112 and 114. 
Formed within the inner surface of the lid 110 is a dispersing chamber 116. 
The exterior surface of the dispersing chamber 116 is closed by a 
dispersing screen 118. The function of the screen 118 is that it is of a 
sufficiently small mesh so that when liquid is supplied into the 
dispersing chamber 116 that it will be substantially evenly distributed 
across the screen 118 prior to entry into the soaker container 52. Liquid 
is supplied into the dispering chamber 116 through conduit 120 formed 
within the lid 110. The conduit 120 terminates in a nipple which in turn 
is connected to a flexible hose 122. Flexible hose 122 is connected to the 
wall of the heater chamber 124. Within the heater chamber 124 is located 
an electrical heating coil 126. The free end of the heater chamber 124 is 
connected to a conduit 128, through a valve 130 to the air compressor 52. 
If, per chance, the soaking container 52 starts to overfill, as from tap 
water from the conduit 82, there is provided an overfill conduit 132 which 
is to conduct the excess water into drain conduit 90. 
The deionized water 32 is to be conducted through conduit 134 into a small 
reservoir 136. From the reservoir 136, the deionized water is to flow 
through conduit 138 through a valve assembly 140 to then be discharged 
into the conduit 128. 
Referring particularly to FIGS. 5 and 6, there is shown a novel type of 
valve 142. The valve 142 is constructed of a lower block 144 and an upper 
block 146. The upper block 146 is fixedly mounted to the lower block 144 
by means of conventional threaded fasteners 148. Both the blocks 144 and 
146 will be constructed of substantially the same material and will 
normally comprise an acid resistant material, such as a plastic. 
Within the block 144 is located an enlarged chamber 150. Inlet conduit 152 
connects with the chamber 150, and an outlet conduit 154 extends from the 
chamber 150. Movably mounted within the chamber 150 is a valve spool 156. 
The valve spool 156 is to be constructed of a magnetizable material. The 
valve spool 156 is coated with a plastic 158. 
Mounted within the block 146 is an electromagnetic coil 160. It is to be 
understood by supplying of a sufficient electrical energy to the coil 160 
that the valve spool 156 will be moved into the upper portion of the 
chamber 150 thereby preventing liquid from being conducted from conduit 
152 into conduit 154. This in essence closes the valve 142. Reversing of 
the magnetic field within the coil 160 or possibly eliminating of the 
magnetic field will cause the valve spool 156 to be moved to the lower 
position shown in FIG. 6. Therefore, this permits liquid to be conducted 
from the conduits 152 into conduit 154. 
Because of the acidic nature of the solution 44, it is desirable that the 
valves 54 and 64 be constructed as per valve 142 to minimize corrosion. 
Also, the valves 58, 60, 84 and 88 may also be constructed in this manner. 
The operation of the pipet washer and dryer 20 of this invention is as 
follows: The pipets that are desired to be washed are located within the 
basket 100. The basket 100 is located within the soaker container 52 and 
the lid 110 is located tightly about access opening 108. As previously 
mentioned, the operator then manually presses button 42. This activates 
the air compressor 53, as well as closes valve 58, opens valve 60 and 
opens valve 54. Also, valves 64, 88, 84, 140 and 130 are closed. The 
heater 124 is inoperative. The air pressure from the air compressor 53 is 
transmitted into the acid storage tank 46 which causes the acid solution 
44 to substantially completely fill the soaker container 52. When the 
container 52 has been sufficiently filled, the air compressor 53 is 
deactivated by float indicator mechanism 86. The acid solution 44 remains 
within the soaker container 52 for a period of time, such as thirty 
minutes to an hour. 
When the operator decides that it is time to proceed with the remaining 
cycles of the pipet washer dryer 20 of this invention, the operator pushes 
button 80. This initially open valves 64 and valve 58. The acid solution 
44 is permitted to flow back into the acid storage tank 46. At this 
particular time, the valve 64 then closes with valve 84 being opened 
permitting tap water to flow and completely fill the soaker container 52. 
When the soaker container 52 is completely filled, the float indicator 86 
causes the valve 84 to close. Usually, the tap water will be located 
within the soaker container 52 for a short period of time, such as two 
minutes. 
At the end of the two minutes time, the valve 88 will be caused to open 
permitting the tap water to be discharged through the drain conduit 90. In 
actual practice, this filling of the soaker container 52 with the tap 
water and discharging it will continue for approximately two hours. 
The final rinse cycle begins with valves 84 and 88 being closed and valve 
140 opened. This causes a metered amount of deionized water to flow from 
the reservoir 136 into the conduit 138. Heater 124 is activated. After the 
conduit 128 contains the metered amount of deionized water, the valve 140 
is closed. The reservoir 136 begins to fill again from the deionized water 
tank 34. The air compressor 53 is activated and valve 130 is opened. As a 
result, the deionized water is moved through and heated by the heater 124, 
through conduit 120, through the dispersing chamber 116 and the dispersing 
screen 118 to be dispersed as a forceful mist into the soaker basket 100. 
This procedure is repeated for a plurality of times, usually three in 
number. 
Referring particularly FIG. 13, there is shown the drying cycle wherein the 
valve 140 is closed. The air compressor 52 is operated continuously in 
this cycle. The valve 130 is open, as well as the heater 124 being 
activated. As a result, heated air is being conducted within the soaker 
basket 100. The outlet for the heated air is to be conducted through the 
valve 88 to be discharged through the drain conduit 90. This drying cycle 
continues usually for an extended period of time in order to insure that 
the pipets 102 and 104 will be substantially completely dried. 
After the pipets have been completely dried, the switch 98 is moved to the 
off position, the lid 110 removed and the basket 100 removed from the 
soaker container 52. The washed and now dried pipets 102 and 104 are to be 
removed from the basket 100 and utilized in the desired manner. Instead of 
the lid 110 being completely removable, the lid 110 may be hinged to 
housing 22. 
Although this invention has been described as being used with only an acid 
solution, it is to be within the scope of this invention to substitute a 
detergent solution for the acid solution.