Multiprogrammable pinch valve module

A pinch valve module comprising a housing, a cylindrical cavity formed in the housing, plural passageways leading from the cavity to the exterior of the housing and spaced about the cavity and a coaxial rotor rotatable within said cavity. The rotor has a diameter less than the diameter of the cavity defining a chamber between its outer wall and the inner cavity wall. Plural spaced pins are located within the chamber and are spaced about the rotor periphery. The rotor has unitary outwardly extending radial protrusions in the form of lobes extending into the chamber. Generally cylindrical tubular rollers or rings are loosely seated about selected ones of said pins within the chamber. Flexible conduits are threaded through said passageways and are disposed along arcuate sections of the chamber walls between the pins and the chamber wall. A stepping motor is coupled to said rotor to translate the lobes past the rings forcing selected ones of the rings against the flexible conduit to pinch same preventing fluid passage therethrough. The valve is programmable by prepositioning the pins and the rings placed thereon. Where rings are absent, no compression is exerted on the conduit. The rotor has an exposed outer disc surface carrying plural spaced arrays of recesses cooperative with microswitches or the like which can control functional operation of the testing system with which the module is associated.

BACKGROUND OF THE INVENTION 
This invention relates generally to means for controlling the transfer of 
fluids through flexible conduits defining flow paths and particularly 
provides a pinch valve module which is capable of operating upon a 
plurality of flexible conduits in preprogrammed sequence and which may be 
combined with like valves to enable control of flow through an extensive 
array of flexible conduits. 
Apparatus intended for the conduct of a plurality of chemical tests 
automatically upon a series of individual samples fed to the apparatus are 
well known to the art. Such automated analysis apparatus is utilized in 
the medical, biological and industrial fields for obtaining diagnostic and 
routine information for empirical, control and even research purposes. 
Problems which had been encountered in manually conducted tests gave rise 
to automated, or at least semi-automated, testing apparatus. 
One considerable problem encountered in manually operated and in automated 
apparatus has involved minimal efficiency of earlier fluid transfer, i.e. 
liquid transfer, in such a manner as to provide quantitatively accurate 
dilutions and satisfactory physical transfer from one testing location to 
another without appreciable loss of precision, accuracy and the fluid 
itself. Another persistent problem has been encountered in switching from 
one fluid source to another. Fluid valves, such as check valves, have been 
used to control the direction of flow as well as the timing of such flow. 
Often, valves are employed which operate upon the flow of fluid through 
flexible conduit by pinching or compressing the conduit. 
Valves such as disclosed and claimed in U.S. Pat. Nos. 8,882,899 and 
3,932,065 have been successfully offered as solutions to the many problems 
encountered such as achievement of precision and accuracy in effecting 
transfer of fluids from one location to another with achievement of 
accuracy and precision. Sealing and/or seating problems previously 
encountered perhaps may have been caused by sediment buildup on the 
sealing mechanism. Lack of quick responsiveness and leakage were the 
result. Mechanical hysteresis or backlash caused by time delay in 
achieving operating in an opening and closing of the valve gave rise to 
lag in the reaction time between initial operation of the valve and the 
actual achievement of such action. Backlash allows additional fluid to 
pass causing error in volume dispensed. Backlash is unpredictable being 
due somewhat to back pressure applied to the valve to cause the valve to 
close, for example. 
Many analytical systems require many individual fluid paths to be monitored 
and further, provide a plurality of flexible fluid conduit to effect and 
to define flow paths for transferring fluids for both delivery and control 
of other functions as well as for the performance of testing procedures. 
Pinch valves had to be provided for each of the flow paths, along with 
their solenoid drivers and controls, the valves functioning as check 
valves, flow control valves or the like. 
It would be more advantageous both for economy and for efficient space 
utilization, to reduce the number of pinch valves needed and improved 
their efficiency. Further, if operation of these valves could be 
simplified so that they could be present without expensive controls, much 
advantage would result. Improved vesatility, if achievable, would also be 
of advantage. Modular valve arrays are desirable. 
It would be highly advantageous to provide a pinch valve module capable of 
being functionally preprogrammed for automatic sequentially timed 
operation further capable of being computer interfaced. 
If the valve module could be provided with means whereby the position of 
the valving means thereof could control the sequential operation of the 
testing apparatus, for example, considerable advantage could ensue. 
SUMMARY OF THE INVENTION 
The invention provides a multiprogrammable pinch valve which includes means 
for threading a plurality of individual flexible conduits through a valve 
body, means for acting upon each of these flexible conduits in a 
programmed manner to change the condition thereof between permitting and 
preventing passage of fluids therethrough, cam and removable floating 
follower means individual to each flexible conduit capable of being 
prepositioned in a variable program of operation by simple manipulations 
placement and number of the follower means and operable by a simple 
stepping motor between various conditions and further capable of being 
ganged in arrays for operation by common drive means. Additionally, means 
are provided enabling the valve to control the sequential operations of 
the testing apparatus associated therewith.

DESCRIPTION OF PREFERRED EMBODIMENT 
The invention provides generally a single pinch valve module having 
multifunctional capability, that is, it is capable of operating upon a 
plurality of individual lines defined by flexible tubing to control flow 
along many different flow paths. Hence, the pinch valve of the invention 
can be substituted for a number of individual conventional pinch valves 
such as employed in fluid transfer systems for analytical systems 
requiring such fluid transfer. 
As described herein the single pinch valve module 10 can be substituted for 
four separate conventional pinch valves and their solenoid drivers in the 
pneumatic/vacuum operated system shown in FIG. 1. 
The analytical system 10 within which the pinch valve module 60 is 
incorporated includes a measuring tube 12 arranged to measure the volume 
of test fluid delivered to scanning vessel 14 preferably of the Coulter 
type carrying a scanning aperture 16 through which a given known volume of 
particles in liquid system in suspension is passed. A pump 18 is provided 
for controlling fluid flow through the system. A cleaner container 20 for 
holding rinse fluid is coupled by way of line 22 and through a check valve 
24 to line 26 leading to the measuring tube 12. At the initial stage, all 
conduits in the valve module are open, the initial pressure and volume 
being set. 
Employing the system 10, a given volume of particulate sample in liquid 
suspension as measured in measuring tube 12 is delivered to the scanning 
vessel 14 and passed through the scanning aperture 16 monitored in 
accordance with a method of particle study such as described in U.S. Pat 
Nos. 2,656,508, 3,549,994 and others. This fluid passes along line 45. 
Vacuum is employed to draw a predetermined volume of sample through the 
scanning aperture 16. Pressurized fluid, air, is employed to rinse the 
measuring tube 12, passing through line 22 and returning through line 46. 
The measuring tube 12 is cleaned, the cleaner container 20 drained and the 
measuring tube 12 dried by pressurized fluid, air. The last step is the 
draining of the full system 10 via line 49 wherein all the liquid is 
directed to the vacuum chamber 38 and the system 10 is ready again for a 
new run. 
During the setting of the initial pressure and volume, the pump 18 operates 
to force liquid from the waste vessel 38 to the vacuum vessel 32 until the 
level of liquid therein reaches the high level electrode 50 of the level 
sensor 40, there being a vent 43 to the atmosphere through the check valve 
47 and waste vessel 38, the pressure within said vessel 38 being 
atmospheric pressure. 
After a selected period of time, the pump 18 starts and sends liquid from 
the vacuum vessel 32 to the waste vessel 38 until the level falls below 
the low level detector 52. The vacuum level is set by the amount of liquid 
sent from the vacuum vessel 32 to the waste vessel 38. 
At the same time, vacuum is applied to scanning vessel 14 to start sample 
aspiration. Air is aspirated from the expanding chamber 44 to remove small 
droplets of liquid from the measuring tube 12, if any are present. 
A constant flow of sample is directed through the scanning aperture 16 
after vacuum is stabilized. This period of time can be electronically 
controlled 
The pinch valve 60 is rotated and vacuum is applied to the upper end of 
measuring tube 12. The sample is aspirated through the scanning aperture 
when the sample reaches the start contact 54. 
Now the rinse cycle begins, with cleaner from chamber 20 being aspirated 
through the measuring tube 12. Thereafter, air transported through the 
vent 43 passing through the measuring tube 12 drains the cleaner chamber 
20 and dries the tube 12. 
The last operation is the draining of the full system 10 by returning to 
the initial condition with release of the vacuum and all liquid being 
directed back to the vacuum vessel 32. 
At the initial stage for setting initial pressure and volume, all lines, 
22, 49, 45 and 46 (FIG. 1) are open. When vacuum is set, only line 46 is 
open. 
The orifice tube 14 is drained with only line 46 open, other lines 22,49,45 
being closed. 
During "counting" all lines but 45 are closed. Rinsing involves opening of 
lines 22 and 46 with lines 49, 45 closed. Draining and drying involves 
opening lines 49 and 46, with lines 22 and 45 closed. 
Final draining involves opening of all valves, the pump 18 deenergized and 
air being drawn through all open conduits 49, 45 and 46. Conduit 22 is 
open but does not occur therethrough. 
Now, attention is directed to the construction of the valve 70 which 
includes a housing 62 comprising a body of generally cylindrical 
configuration having a circumferential wall 66, a top wall 68, a shelf 70, 
a cavity 72 and a coaxial through passage 74 through the body 64 to 
accomodate rotor 76. The cavity 72 includes four radial extensions 78, 
each extending through the circumferential wall 66 and opening exterior of 
the housing 62. 
The cam rotor 76 is seated in central passage 74 coaxial therewith. The cam 
rotor 76 comprises a cam disc 80, a drive key 82 and programming disc 84. 
The cam rotor 76 and the programming disc 84 are provided with threaded 
passageways 86 for accomodating screws 88. The rear face 90 of the cam 
disc 80 has an outwardly opening elongate recess 92 for accomodating the 
key 94 of drive key 82, key 82 also being formed with a cross slot 96 for 
receiving an actuator 83 (shown in FIG. 3) for rotating the assembled 
rotor 96. 
The programming disc has a concentric portion 98 for receipt within the 
passage 74 and a circumferential recess 100 for seating upon rear shelf 
102 formed in the body 64 and engaged sealingly upon the rear face 104 of 
the cam disc 80. The outer face 105 of programming disc 84 is provided 
with a plurality of recesses or indentations 106 disposed in groups about 
its central axis. The recesses or indentations 106 function as programming 
means cooperative with arrays of micro-switches for controlling the 
functional operation of the system within which the module 10 
operationally is installed. 
The cam disc 80 includes a peripheral lip 108 carrying the radial lobes 110 
which are arranged symmetrically disposed about the periphery of said disc 
80, each of the lobes 110 terminating in cam-like surfaces 112. The lobes 
110 extend into the chamber defined between the cam disc 80 and the shelf 
70. 
The lip of cam disc 80 of rotor 76 seats on the floor of cavity 72 with the 
lobes 110 radially extending just short of the pins 116. Hollow 
cylindrical rings or rollers 118 are seated loosely over the selected ones 
of the pins 116 and function as cam followers. The rings 118 are formed of 
a slightly resilient plastic material, such as Nylon or Teflon (registered 
trademaker of DuPont Co.). 
The radial outwardly extending lobes 110 are capable of engaging the 
rollers 118 as the cam surfaces 112 pass same during rotation of rotor 76, 
thereby shifting their axial position on the pins 110. The shelf 70 is 
divided into arcuate sections between the wall 106 of extensions 78 of 
cavity 72 with same arranged so that when flexible tubing 120 is threaded 
along the recess facing wall of shelf 70, after entering through one of 
the cavity extensions 78 along the shelf wall to be directed through a 
next adjacent radial extension to a destination. When a ring 118, urged by 
the cam surface 112 of lobe 110, engages the flexible tubing 120 during 
the course of rotation of the rotor 76, the flexible tubing is compressed 
to close off flow therethrough. The timing as well as the length of time 
during which the tube is compressed or pinched depends upon the number and 
location of the rollers 118 on pins 116. Top cover 119 is snugly fitted 
over the valve body to complete the assembly. 
In FIG. 4, the pinch valve module 60 is illustrated in one of its 
operational conditions. Four flexible tubes, 120, 122, 124 and 126 are 
shown threaded through the respective radial extensions of cavity 72. The 
path taken by flexible tube 120 passes ring 118, ring 128 and ring 130. 
The path taken by flexible tube 124 passes only rings 136 and 138, while 
the path taken by flexible tube 126 passes rings 140, 142 and 144. In the 
condition illustrated in FIG. 3, the rotor 76 is positioned so that the 
respective cam surfaces are engaged with rings 118,136 and 140 compressing 
tubes 120, 124 and 126 so that only the fluid line represented by tube 122 
is open and flow is allowed therethrough. Assuming that operation of the 
pinch valve module 60 is effected by causing the rotor 76 to rotate in a 
counter-clockwise direction (arrow), the stepped movement of said rotor 
one step in the counter-clockwise direction causes the cam surfaces to 
impress only upon ring 142. This results in opening flexible tube 120 and 
124, leaving tube 122 open and tube 126 closed. The next stepped movement 
one step counter-clockwise causes the cam surfaces to impact upon rings 
132, 128 while moving to a location where no ring is mounted upon a pin 
116 to effect lines 124 and 126. Thus flexible tubes 124 and 126 are open 
while flexible tubes 120 and 122 are pinched closed. When the cam surfaces 
112 engage the rings, i.e. 118, the rings are shifted laterally and 
slightly compressed compared to the condition of such rings as represented 
by rings 128 and 130 in FIG. 4, for example. 
Referring to FIG. 3, the indentations 106 in the surface 105 of disc 84 
arrayed in groups along radial lines taken through their centers and 
passing through the center axis of the rotor 76. Arranged singly or in 
rows of two or three indentations, they will cause the opening or closing 
of suitably biased microswitch actuators (not shown) proximate to the 
drive means 83, said microswitches effecting the functional control of the 
testing apparatus with which the valve module 60 is associated. Obviously, 
the indentions or recesses can comprise, instead, protrusions also 
operative upon suitable microswitch actuators. 
The pinch valve module 10 herein described replaces four conventional pinch 
valves. It should be understood that a single module could replace as many 
as eight separate pinch valves or check valves, as eight flexible tubes 
can be accomodated in the present structure. Further, the single module 
could be combined with additional modules in gangs or stacks, driven off 
the same simple motor, which can be stepped progressively by a 
conventional timer motor. The roller 100 could be arranged so that the 
operation could be of the break-before-make or make-before-break modes. 
In both the standby and the fill modes, all the tubing is in the open 
condition. The four-lobed cam operates upon the four separate tubes as if 
they were separate valves. 
If one section, i.e. the arcuate wall section, of the cavity, has six 
rolling position, pins 116 and only the first and fourth positions need 
contain rings such as ring 118. The tubing will be closed off during the 
first and fourth phases of the cycles performed, and open during the other 
phases. 
Variations are capable of being made without departing from the spirit or 
scope of the invention as defined in the attached claims.