U.S. patent number 3,654,959 [Application Number 05/069,830] was granted by the patent office on 1972-04-11 for fluid supply control method and apparatus for periodic, precise fluid merger.
This patent grant is currently assigned to Technicon Instruments Corporation. Invention is credited to Aaron Kassel.
United States Patent |
3,654,959 |
Kassel |
April 11, 1972 |
FLUID SUPPLY CONTROL METHOD AND APPARATUS FOR PERIODIC, PRECISE
FLUID MERGER
Abstract
New and improved fluid supply control method and apparatus for
periodic fluid merger which are particularly adapted to the
periodic, precisely timed introduction of precisely and uniformly
sized fluid segments into a fluid stream are disclosed and comprise
a segmenting fluid supply line which respectively connects with a
pressurized source of said segmenting fluid at substantially
constant pressure and with the line in which said fluid stream is
flowing. First and second, quick-acting flow interrupting means are
operatively associated with said fluid supply line at spaced
locations thereon, and a cavity of substantially constant volume is
formed between said flow interrupting means. In operation, and for
the formation of each of said segments, said first flow
interrupting means are opened to effect the filling of said cavity
with said pressurized fluid whereupon said first flow interrupting
means are closed and said second flow interrupting means opened to
effect the flow of said pressurized fluid from said cavity into
said fluid stream to form said segments. A form of the invention is
disclosed wherein said fluid supply line is constituted by a
compressible, resilient tube and said flow interrupting means
comprise means to compress and close said tube at spaced locations
thereon. In this disclosed form, the cavity is formed by the volume
of the tube which extends between said flow interrupting means.
Inventors: |
Kassel; Aaron (Tarrytown,
NY) |
Assignee: |
Technicon Instruments
Corporation (Tarrytown, NY)
|
Family
ID: |
22091468 |
Appl.
No.: |
05/069,830 |
Filed: |
September 4, 1970 |
Current U.S.
Class: |
137/605; 137/154;
222/450; 137/101.31; 222/4; 251/9 |
Current CPC
Class: |
G01N
35/08 (20130101); Y10T 137/2541 (20150401); Y10T
137/87676 (20150401); Y10T 137/2931 (20150401) |
Current International
Class: |
G01N
35/08 (20060101); F17d 001/08 (); F16k
019/00 () |
Field of
Search: |
;137/1,154,605 ;251/4,9
;222/4,450,452 ;23/23A ;356/181 ;73/423R,423A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nilson; Robert G.
Claims
What is claimed is:
1. In fluid supply control apparatus for the introduction of a
fluid into a fluid stream, the improvements comprising, a fluid
supply line of compressible resilient material and having the
outlet thereof operatively connected with the line in which said
fluid stream is flowing, a pressurized source of the fluid to be
introduced, said source being operatively connected with the inlet
of said fluid supply line, first and second flow interrupting means
operatively associated with said fluid supply line at spaced points
thereon, said first flow interrupting means being located between
said fluid source and said second flow interrupting means, a cavity
of substantially constant volume formed between said first and
second flow interrupting means, and means to operate said flow
interrupting means to open said first flow interrupting means to
enable the filling of said cavity with fluid from said source, to
then re-close said first flow interrupting means and open said
second flow interrupting means to enable the flow of said fluid
from said cavity for introduction into said fluid stream, and to
then re-close said second flow interrupting means, said first and
second flow interrupting means comprising first and second arm
members, respectively, which are independently and pivotally
moveable between a first or operative position to compress and
close said fluid supply line and a second or inoperative position
to release and open said fluid supply line.
2. In apparatus as in claim 1 wherein, said flow interrupting means
comprise biasing means operatively connected to said first and
second arm members and operable to bias the same to the respective
operative positions thereof.
3. In apparatus as in claim 2 wherein, said flow interrupting means
operating means comprise cam means operatively associated with said
first and second arm members and operable to drive the same to said
inoperative positions thereof.
4. In apparatus as in claim 3 wherein, said cavity is formed by the
volume of the length of said tube which extends between said spaced
tube locations.
5. In apparatus as in claim 4 wherein, said material is silicone
rubber.
6. In apparatus as in claim 1 wherein, said flow interrupting means
operating means comprise cam means operatively associated with said
first and second arm members and operable to drive the same to said
inoperative positions thereof.
7. In apparatus as in claim 1 wherein, said cavity is formed by the
volume of the length of said tube which extends between said spaced
tube locations.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to new and improved fluid supply control
method and apparatus for periodic precise fluid merger and, more
particularly, to such method and apparatus as are particularly
adapted to the periodic, precisely timed introduction of precisely
and uniformly fluid segments into a fluid stream.
2. Description of the Prior Art
In the operation, for example, of automatic, substantially constant
flow rate and continuous flow fluid sample supply, treatment and
analysis apparatus of the nature disclosed in U.S. Pat. No.
3,134,263 issued May 26, 1964 to Edward B.M. DeJong and assigned to
the assignee hereof, and/or U.S. Pat. No. 3,241,432 issued Mar. 22,
1966 to Dr. Leonard T. Skeggs, et al., and assigned to the assignee
hereof, it may be understood that a continuous stream of fluid
sample segments, as spaced by intervening segments of a separating
fluid or fluids in the nature of air segments for wash and sample
segment delineation purposes, is merged in substantially fixed
proportion with a similarly segmented stream of a suitable
color-producing reagent to effect a desired color-producing
reaction and enable subsequent colorimetric analysis of said sample
segments with regard to a constituent of interest thereof.
Preferably, the segmentation and merger of said segmented sample
and reagent streams are effected in precisely synchronized manner
so that sample-reagent segment merger rather than, for example,
sample stream air segment-reagent segment, or reagent stream air
segment-sample segment, takes place to thus promote to the maximum
possible extent the desired sample-reagent mixture with attendant
like promotion of the color producing reaction of interest. Too, it
is believed clear that improperly timed or imprecise air
segmentation of the reagent stream may result in unacceptable
variation in the desired sample-reagent mixture proportion.
In prior art apparatus of the type discussed hereinabove, the
requisite air segmentation of the reagent stream is effected
through the use of multiple compressible tubes of a peristaltic
proportioning pump of the nature disclosed, for example, in U.S.
Pat. No. 3,227,091 issued Jan. 4, 1966 to Jack Isreeli, et al., and
assigned to the assignee hereof, and/or U.S. Pat. No. 3,306,229
issued Feb. 28, 1967 to William J. Smythe. Although this means of
air segmenting the reagent stream of interest is satisfactory, it
may be understood that the use thereof in improved versions of said
automatic, substantially constant flow rate sample supply,
treatment and analysis means which are operable, to significant
advantage, with substantially reduced flow rates and substantially
reduced sample volumes, and at substantially increased sample
analysis rates, can be lead to problems which result from pump tube
fatigue, due to repeated occlusion thereof over long periods of
time, with attendant change in the delivery rate of said pump tubes
and resultant improperly timed and/or imprecisely metered
segmentation of said reagent stream.
An alternative prior art method of achieving the desired
air-segmentation and supply of said reagent stream for synchronized
merger with said sample stream involves the utilization of constant
flow pressure pumping systems including relatively complex and
expensive flow regulators of somewhat questionable reliable and
which, in any event, require frequent checking and adjustment, all
to significant disadvantage as should be obvious.
OBJECTS OF THE INVENTION
It is, accordingly, an object of this invention to provide new and
improved fluid supply control method and apparatus for periodic
precise fluid merger which are particularly adapted to the
periodic, precisely timed introduction of precisely and uniformly
sized fluid segments into a fluid stream.
Another object of this invention is the provision of apparatus as
above which require the use of only readily available, relatively
inexpensive components of proven dependability in the fabrication
thereof, and which are of basically simple construction and manner
of operation, to thereby provide for relatively low apparatus costs
and long periods of accurate, substantially maintenance-free
apparatus operation.
A further object of this invention is the provision of method and
apparatus as above which are particularly, through by no means
exclusively, adapted to the precisely synchronized and metered
air-segmentation of a reagent liquid stream in automatic,
substantially constant flow rate fluid sample supply, treatment and
analysis apparatus of the type disclosed in U.S. Pat. Nos.
3,134,263 and/or 3,241,432, respectively.
SUMMARY OF THE INVENTION
As disclosed herein, the new and improved fluid supply control
method and apparatus of the invention for the periodic, precisely
timed introduction of precisely and uniformly sized fluid segments
into a fluid stream comprise a fluid supply line which merges into
the line in which said fluid stream is flowing.
First and second, quick-acting flow interrupting means are
operatively associated with said fluid supply line at spaced or
upstream and downstream points thereon, and a cavity of
substantially constant volume V is provided between said flow
interrupting means. A source of the fluid of interest at
substantially constant pressure P is operatively associated with
the inlet of said fluid supply line. Operating and control means
are operatively associated with the flow interrupting means and are
effective to independently operate and control the same in
accordance with a precisely predetermined operational cycle.
In operation, and with both said first and second flow interrupting
means initially closed, said first or upstream flow interrupting
means are opened for a predetermined time to effect the filling of
the cavity with the fluid of interest at the substantially constant
pressure P. Following this, said first flow interrupting means are
re-closed and maintained closed for a second predetermined period
of time, at the expiration of which said second or downstream flow
interrupting means are opened for a third predetermined period of
time to enable the flow of the fluid from the cavity into the line
in which said fluid stream is flowing to form a fluid segment of
precisely determined size therein. Then, said second flow
interrupting means are re-closed and maintained closed, along with
said first flow interrupting means, for a fourth predetermined
period of time, at the expiration of which the described
operational cycle is repeated.
In one disclosed form of the invention, the fluid supply line takes
the form of a tube of any suitably compressible and resilient
material of sufficient strength characteristics in the nature, for
example, of silicone rubber, while said first and second flow
interrupting means take the form of a cam-operated arm assembly
having first and second arms which are independently operable to
compress and close said tube at spaced points thereon. In this form
of the invention, the cavity of volume V is formed by the tube
length which extends between said spaced points.
In another disclosed form of the invention, the flow interrupting
means are formed by first and second quick-acting valve means,
while the cavity may be formed therebetween in any practicable
manner.
DESCRIPTION OF THE DRAWINGS
The above and other objects and significant advantages of this
invention are believed made clear by the following detailed
description thereof taken in conjunction with the accompanying
drawings wherein:
FIG. 1 is a schematic diagram of new and improved fluid supply
control apparatus constructed and operative in accordance with the
teachings of this invention;
FIGS. 2A and 2B are timing diagrams drawn to the same time scale
and illustrating the operation of the fluid flow interrupting means
of the apparatus of FIG. 1;
FIG. 3 is a partially schematic side view with parts in cross
section of a form of the apparatus of FIG. 1;
FIG. 4 illustrates the fluid flow interrupting means of the
apparatus of FIG. 3 in a first operative position thereof;
FIG. 5 illustrates the fluid flow interrupting means of the
apparatus of FIG. 3 in a second operative position thereof; and
FIG. 6 illustrates an alternate form of fluid flow interrupting
means operating and control means.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a fluid line is indicated at 10, and pump
means or the like are schematically indicated at 12 and are
operatively associated as shown with line 10 to pump a stream R of
fluid therethrough from a non-illustrated fluid source at
substantially constant flow rate in the indication direction.
New and improved fluid supply control means constructed and
operative in accordance with the teachings of this invention for
the periodic, precisely timed introduction of precisely sized fluid
segments S to the fluid stream R are illustrated schematically at
14, and comprise a segmenting fluid supply line 16 which merges as
shown with the fluid supply line 10. A source of the segmenting
fluid of interest at substantially constant pressure P is indicated
schematically at 18 and is operatively connected as shown to the
inlet of the fluid supply line 16 for the supply of said segmenting
fluid thereto at said substantially constant pressure P. The said
pressure P is, of course, sufficiently higher than the pressure at
which the fluid stream R is pumped through fluid line 10 to insure
flow in the indicated direction.
Quick-acting flow interrupting means 19 which may, for example,
take the form of quick-acting valve means are indicated
schematically at 20 and 22 and are operatively disposed as shown at
spaced locations in the segmenting fluid supply line 16. Valve
operating and control means are indicated schematically at 24 and
are operatively associated as indicated by the dashed lines with
each of the valve means 20 and 22 to effect the respective openings
and closings thereof in precisely timed sequence as described in
greater detail hereinbelow. A cavity of volume V is schematically
indicated at 26 and is formed as shown by or in the segmenting
fluid supply line 16 between the respective valve means 20 and
22.
In operation, under steady state conditions with the fluid stream R
flowing through fluid line 10 at substantially constant flow rate
and the segmenting fluid being supplied to supply line 16 at
substantially constant pressure P, and also referring now to the
valve operating timing diagrams of FIGS. 2A and 2B which are, of
course, drawn to the same time scale and wherein the square waves
28 illustrate the openings of valve means 20 and the square waves
30 illustrate the openings of valve means 22, it may be seen that
valve means 20 will be opened first, under the control of valve
operating and control means 24, for a time t1 to effect the filling
of cavity 26 with the segmenting fluid substantially at pressure P
since valve means 22 remain closed. At the expiration of time t1,
valve means 20 will re-close to thus leave the cavity 26 filled
with the segmenting fluid substantially at pressure P. This
condition is continued for a time t2, at the expiration of which
valve means 22 are opened as indicated under the control of valve
operating and control means 24 for a time t3 to thus effect the
flow of the pressurized fluid from cavity 26 through said valve
means and supply line 16 into the fluid stream R flowing in fluid
line 10 to form a fluid segment S of the desired volume
therein.
At the expiration of time t3, valve means 22 are re-closed and
maintained closed to thus complete an operational cycle of the
fluid supply control means 14 of the invention and effect the
formation of a segment S in the fluid stream R.
At the expiration of time t4, the succeeding cycle of the fluid
supply control means 14 of the invention is commenced as indicated
to form the succeeding segment S in the fluid stream R by the
re-opening of the valve means 20 for a time t1. Said succeeding
cycle is completed by the subsequent re-closure as indicated of the
valve means 20 for a time t2, the opening of valve means 22 for a
time t3, and the re-closure of the latter, respectively.
The total time T which elapses between each opening of the valve
means 20 is made equal as indicated to the total time T which
elapses between each opening of the valve means 22, while the
frequency of segment formation in the fluid stream R is equal to
1/T and may thus be precisely controlled as desired through control
of the time T. Too, the combined elapsed times t4 + t1 + t2 in that
order between the closing and opening of the valve means 22 may,
when determined in relationship to the substantially constant
velocity of flow of the fluid stream R in line 10, be utilized to
precisely control the spacing of the fluid segments S in said fluid
stream.
The size of the respective segments S in the fluid stream R may be
precisely determined through proper choice of the fluid pressure P
and the volume V of cavity 26, whereby may be understood that the
respective times t1 and t3 that the valve means 20 and 22 are
maintained open will be rendered substantially non-critical in this
regard within reasonable limits.
Precise uniformity in size and spacing of the respective fluid
segments are respectively achieved through the maintenance of the
pressure P and cavity volume V at substantially constant values,
and through the maintenance of the combined elapsed times t4 + t1 +
t2 substantially constant.
A form of the new and improved fluid supply control means for use
in the precisely timed segmentation of a color-producing reagent
liquid stream by the introduction of precisely and uniformly sized
air segments thereto is indicated generally at 34 in FIG. 3, and is
again operatively associated with a fluid line 10 which, in this
instance, takes the form of a reagent supply line. Reagent liquid
pump means are again schematically indicated at 12 and are, of
course, operative to pump a stream of said reagent liquid from a
non-illustrated source thereof through said reagent supply line at
substantially constant flow rate.
The segmenting fluid supply line as generally indicated at 16 here
takes the form of a tube 36 of any inert, readily compressible
material of suitable resiliency and strength characteristics in the
nature, for example, of silicone rubber. Since, in this instance,
the segmenting fluid is air, it may be understood that the
segmenting fluid source, as again indicated schematically at 18,
would, of course, be a suitable source of air at substantially
constant pressure P in the range, for example, of 5 to 8 psi. The
operative connection of the air supply tube 36 to the reagent
liquid line 10 is preferably effected as illustrated by the simple
extension of an air inlet nipple 38 from the latter and the
stretching of the end of said tube thereover to form a fluid-tight
connection therebetween.
Referring now to the quick-acting flow interrupting means 19, the
same may be seen to comprise generally "S" shaped arms 40 and 42
which are respectively pivotally supported as indicated from common
pivot means 44. A tension spring 46 is provided to extend as shown
between the respective lower arm portions to return the same to the
respective illustrated positions thereof.
A platen is indicated at 48 and is operative to support the lower
surface portion of the tube 36 and prevent downward movement
thereof.
The arms 40 and 42 respectively comprise generally rounded lower
extremities as indicated at 50 and 52, each of which is operative
when in the depicted position thereof to compress the adjacent
portion of the compressible tube 36 as shown against the upper
surface of the platen 48 to close said tube portion and prevent
fluid flow therethrough. The cavity 26 of volume V is, of course,
formed as indicated by the volume of the length of the tube 36
which extends between the closed portions thereof.
Referring now to the valve operating and control means 24, the same
are constituted in part by a cam 54 having a cam roller 56
supported for rotation as shown from the lower portion thereof. The
cam 54 is, in turn, fixedly attached to a cam shaft 58 which is
drivable as indicated in both directions to drive the cam 54
between first and second operative positions thereof. More
specifically, and with cam 54 driven to the first operative
position thereof as seen in FIG. 4, the generally rounded end 50 of
arm 40 will be raised from occluding contact with the relevant
portion of tube 36 to thus enable fluid flow therethrough.
Alternatively, with cam 54 driven to the second operative position
thereof as seen in FIG. 5, the generally rounded end of arm 42 will
be raised from occluding contact with the relevant portion of the
tube 36 to likewise enable fluid flow therethrough.
The fluid supply control means 34 of FIG. 3 are particularly
adaptable for use in the air-segmentation of a reagent liquid
stream in automatic, substantially constant flow rate liquid sample
supply, treatment and analysis apparatus of the nature disclosed,
for example, in U.S. Pat. Nos. 3,134,263 and 3,241,432. Each of
these apparatus comprises a peristaltic proportioning pump of the
nature disclosed in somewhat greater detail, for example, in U.S.
Pat. No. 3,277,091, which functions to provide a continuous supply
of an air-segmented liquid sample stream for sample treatment and
analysis. In such apparatus the respective air-segmented liquid
sample and reagent streams are merged to effect a desired
color-producing reaction, and it may be understood that such merger
is preferably synchronized to insure liquid sample segment-reagent
segment merger rather than, for example, air segment-reagent
segment or air segment-liquid sample segment merger. Too, it may
readily be understood to be of significant import that the
proportion in which said liquid sample and reagent streams are
mixed be maintained substantially constant, and that improperly
timed or imprecisely metered segmentation of said reagent stream
can, of course, result in unacceptable variation in said
proportion.
Peristaltic proportioning pumps of the nature disclosed in said
United States Patents may be understood to be operable through the
concomitant and progressive occlusion of two or more compressible
pump tubes by a plurality of moveable pump rollers to concomitantly
pump fluids therethrough at substantially the same constant flow
velocity, and it is believed clear that synchronization of the
operation of the fluid supply control means 34 of FIG. 3 with the
operation of said pump rollers will be effective to achieve the
desired synchronization of the respective air-segmented liquid
sample and reagent liquid streams.
More specifically, and referring again to FIG. 3, a peristaltic
proportioning pump of the type discussed hereinabove is indicated
schematically at 60 and may be understood to be operative to supply
an air-segmented liquid sample stream, comprising alternating
liquid sample segments SA and air segments S, through conduit 62
for merger as indicated with the air-segmented reagent stream R. A
dashed line extends from the proportioning pump 60 to the cam shaft
58 and indicates the drive of the latter to move the cam 54 between
the first and second positions thereof as respectively illustrated
in FIGS. 4 and 5 in substantial synchronism with the movement of
the non-illustrated pump rollers.
In operation for the system application illustrated in FIG. 3, and
assuming steady state operational conditions to have been reached,
it may be understood that an operational cycle of the fluid supply
control means 34 of the invention will be commenced by the drive of
the cam 54 to the first position thereof as depicted in FIG. 4 for
the time t1 of FIG. 2A to lift end portion 50 of arm 40 to open the
relevant portion of the tube 36 and enable the filling of cavity 26
with pressurized air at substantially the constant pressure P, it
being understood that the strength characteristics or resistance to
expansion of any significance of the tube 36 are, of course, chosen
to substantially preclude any expansion of the volume V in response
to the pressurization thereof as described. Thus the volume V is
maintained substantially constant as desired and fatigue of the
tube as would accompany repeated stretching thereof also
substantially precluded.
At the expiration of time t1, cam 54 is returned to the inoperative
or central position thereof of FIG. 3, whereby tension spring 46
will return arm 40 to the position thereof depicted in said FIG. to
re-close the relevant portion of tube 36 and effect the entrapment
of the volume V of air at substantially the pressure P in the
cavity 26.
At the subsequent expiration of time t2 of FIG. 2B, the cam 54 will
be driven to the second position thereof as illustrated in FIG. 5
for the time t3 to raise the end portion of arm 42 to open the
relevant portion of the tube 36 and enable the flow of the
pressurized air from the cavity 26 through the downstream portion
of tube 36, into and through the inlet nipple 38, into the reagent
liquid stream R flowing in reagent supply line 10 to thus form the
air segment S precisely of the desired size therein.
At the subsequent expiration of time t4 of FIG. 2B, cam 54 is
returned to the inoperative or central position thereof of FIG. 3
whereby tension spring 46 will return arm 42 to the position
thereof depicted in said FIG. to re-close the relevant tube portion
and complete one air-segment introduction cycle of operation.
Operation of the fluid supply control means 34 is, of course,
automatically continuous as described.
An alternate form of drive means for driving cam shaft 58, and
accordingly cam 54, between the first and second operative
positions of the latter is schematically illustrated in FIG. 6 and
comprises a readily reversible electric drive motor 64 which is
drivingly connected as indicated by line 66 to the cam shaft 58 so
as to drive the same as described. Motor timer and control means
are schematically indicated at 68 and are operatively connected as
shown to drive motor 64 by line 70 to control the operation thereof
in precise accordance with a desired operational sequence. A wide
variety of still other and different cam shaft drive means will
readily occur to those skilled in this art.
Proper choice as described of the material from which the tube 36
is made will provide for high resistance to fatigue thereof for
long operational periods despite the repeated opening and closure
of the effective tube portions by the arm members 40 and 42. The
fatiguing effects of such repeated tube openings and closures over
long period of time can, in any event, be substantially reduced by
the simple expedient of periodically shifting the tube 36
longitudinally relative to the platen 48 and arm members 40 and 42
to thereby periodically expose different tube portions to said
repeated openings and closures.
Although disclosed hereinabove by way of illustration as applied to
the precise control of the supply of a segmenting fluid to segment
another fluid stream, it is clear that the new and improved fluid
supply control method and apparatus of the invention are by no
means limited to such application, but rather, may be utilized with
equally significant advantage in a very wide variety of
applications other and different than stream segmentation
applications wherein the periodic and precisely timed merger of two
fluids in precisely predetermined proportion is desired. Too, the
method and apparatus may, in any event, be alternatively utilized,
for example, to periodically merge a liquid with a liquid, a liquid
with a gas, or a gas with a gas.
While I have shown and described the preferred embodiment of my
invention, it will be understood that the invention may be embodied
otherwise than as herein specifically illustrated or described, and
that certain changes in the form and arrangement of parts and in
the specific manner of practicing the invention may be made without
departing from the underlying idea or principles of this invention
within the scope of the appended claims.
* * * * *