Total containment device for connect/disconnect of plastic tubes

A device for selectively connecting and disconnecting plastic tubes includes a welder. A carriage is located in the welder for conveying a heated wafer through the welder. A pair of arms is mounted in the welder with each arm having a tube holding pocket which extends across its respective arm. The arms are movably mounted to generally align the pockets with a gap therebetween. Each of the arms has a clamp for selectively clamping a tube in its pocket. A wafer removal station is in the welder downstream from the arms. The carriage is driven to the wafer removal station so that the wafer first passes through the gap to contact the tubes and then the wafer passes into the removal station so that it may be removed from the carriage and the carriage may be returned to its starting location. The welder includes a computer for controlling the operation and synchronizing the timing of the carriage and the arms to automate the welder.

BACKGROUND OF THE INVENTION 
The above noted parent applications, deal with various techniques for the 
total technique welding of plastic tubes where no contaminants can enter 
or leave the tube lumen. In general, the welding techniques involve an 
axially aligned melt/wipe process where the ends of the tube sections are 
melted to be rendered into a molten state and then pressed together to 
become integral. 
The above techniques are particularly desirable for wide spread uses 
including CAPD, blood processing and other techniques where it is 
necessary to replace used consumables. In such practices it is necessary 
to cut the tube leading from the used bag to the patient and then weld a 
new tube section from a fresh bag to the tube section leading from the 
patient. It would be desirable if the tube cutting or disconnect procedure 
or the tube joining or connect procedure could be made as simple as 
possible in order to avoid difficulties in performing these procedures. 
The prior art devices for connecting and disconnecting plastic tubes 
requires the manual actuation of various switches to individually control 
the operation of the different components. It would be desirable if such a 
device could be automated in its operation. 
It would also be desirable if such a device for performing the above 
procedures could include various safety mechanisms to assure proper 
operation of the device. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide sterile tube connect/disconnect 
techniques which meet the above needs. 
A further object of this invention is to provide a device for accomplishing 
such techniques wherein there is assurance that the device will operate in 
a proper manner. 
In accordance with this invention a single device is used for selectively 
connecting and disconnecting plastic tubes. The device includes a welder 
having a carriage for transporting a heated wafer. A pair of arms is 
provided in the welder each with a tube holding pocket which extends 
across its respective arm. The arms are pivotally mounted so that the 
pockets can be generally aligned. Each of the arms includes a clamp for 
selectively clamping a tube section in its pocket. A wafer removal station 
is located in the welder downstream from the arms. The carriage is driven 
to the wafer removal station with the wafer passing through the gap 
between the tubes and melting the tubes by the tubes being pressed toward 
the wafer so that the melted ends of the tubes may be welded together 
after the wafer is transported to the removal station during a connect 
operation. 
During the disconnect operation the same device is used wherein a single 
tube is located in both pockets spanning the gap between the pockets and 
the heated wafer cuts through the tube to perform the disconnect 
operation. 
A computer controls the operation and synchronizes the timing of the 
carriage and of the arms to automate the device. 
In a preferred practice of this invention the removal station includes 
clench blocks for cooling the wafer. Negative ion generator means are 
provided to dissolve any aerosol resulting from the heated tubes. The 
clamps may include serrated clamp blocks which could be used for reopening 
a welded tube in the connect mold by first rotating the welded tube about 
900 so that its flat side is moved from a horizontal to a vertical 
position by pressing the serrated clamp blocks against the welded 
connection of the two tubes. The connection that the tubes are moved to a 
generally circular cross-section thereby opening communications between 
the two welded tube sections.

DETAILED DESCRIPTION 
The present invention is directed to the various techniques disclosed in 
the parent applications and more particularly to a device capable of 
effectively performing the tube connect or the tube disconnect operations 
such as generally described in the parent applications. The details of the 
parent applications are incorporated herein by reference thereto. As 
illustrated herein the device for selectively connecting and disconnecting 
plastic tubes comprises a welder 10 which generally includes a chassis or 
body member with a hinged lid or cover 12. The casing for welder 10 may be 
a lower shell 11 detachably secured to an upper shell 13 by suitable 
fasteners. Lid 12 is hinged at one end to upper shell 13. Cover 12 may be 
reliably held in its closed position in any suitable manner, such as by a 
magnetic closure 14 which is magnetically attracted to a portion of the 
welder body. When it is desired to use welder 10 cover 12 would be pivoted 
to the open position shown in FIG. 3. 
In general, welder 10 operates by using a heated disposable wafer 16 which 
performs a melt/wipe operation during the connect procedure and which 
forms a cutting operation during the disconnect procedure. Wafer 16 would 
be mounted in a suitable holder 18. As shown in FIGS. 6-7, holder 18 has a 
slot into which wafer 16 is detachably mounted with the wings 20 of wafer 
16 abutting against lower block portion 22 of holder 18. A pair of notches 
24 is formed between lower block portion 22 and upper block portion 26 of 
holder 18. Wafer 16 also includes a notch or cut out for purposes later 
described. 
Welder 10 has a slot 30 exposed from its top surface with the upstream end 
32 of the slot 30 being of a sufficient width to permit wafer 16 and its 
holder 18 to be inserted into the slot. The upstream wide end 32 of slot 
30 may be considered the home position. Slot 30 engages notches 24 and 
forms a track for carrier 18. A pair of tapered spring arms 34 are 
provided in the bottom of slot 30. Arms 34 are dimensioned to fit against 
the wafer 16 when holder 18 is at the end of slot 30. Arms 34 are 
connected to a heater to heat wafer 16. 
A carriage 36 is located along the track formed by slot 30 remote from home 
position 32. Carriage 36 includes a spring mounted pawl 38 (FIG. 9) which 
engages cut out 28 of wafer 16 to lock wafer 16 to carriage 36 and permit 
holder 18 to be -moved back toward the home position 32 while wafer 16 
remains locked to carriage 36 thus disengaging wafer 16 from holder 18. 
Carrier 18 may then be removed from welder 10 when it returns to the home 
position 32. A spring arm 40 (FIG. 13) is located at the starting position 
of carriage 36 to lock carriage 36 in that position until carriage 36 is 
driven in a downstream direction as later described. 
Suitable heater elements connected to ar-Ms 34 heat wafer 16 when wafer 16 
is mounted to carriage 36 while carriage 36 is in its starting position. 
As shown in FIG. 9 a spring arm 42 is mounted at the starting position of 
carriage 36 and is urged into contact with wafer 16 while carriage 36 is 
in the starting position. Arm 42 functions as a sensor during later 
operation of welder 10 to detect the passage of wafer 16 in a downstream 
direction. 
Welder 10 also includes a pair of pivotable arms 44,44 pivoting around 
pivot pins 46,46 so that the arms 44,44 may move in a horizontal plane. 
As shown for example in FIG. 20 clamp holder arms 44 include an off-set 
extension 48 which is disposed for sliding under bracket 50. Bracket 50 
thus assures that the pivoted clamp holder arms 44 are maintained in their 
proper horizontal orientation. As also shown in FIG. 20 a clamp mechanism 
is secured to each holder arm 44. The clamp mechanism comprises a base 
clamp 52 and a lid 54. Base clamp 52 is fixedly mounted to its respective 
arm 44 while lid 54 is pivoted about pin 56 to base clamp 52 so that the 
lid can be moved to its open and closed position. Lid 54 includes a handle 
portion 53 pivoted about pin 55 to the main portion of lid 54. Handle 
portion 53 is generally L-shaped with an extension 57 having a roller 60 
which extends longitudinally across extension 57. Base clamp 52 includes a 
lock lip 58. Lid 54 is moved to its closed position by grasping handle 53 
and rotating lid 54 toward base clamp 52. Continued movement of handle 53 
causes roller 60 to be disposed under lock lip 58 to effectively lock the 
clamp lid 54 against base clamp 52. 
As illustrated in various figures such as FIG. 20, a pocket 62 is formed in 
base clamp 52. Pocket 62 extends completely across base clamp 52 as 
illustrated for example in FIGS. 10 and 18. It is noted that FIG. 9 shows 
the arms 44 with the clamping mechanisms removed so that the details of 
arms 44 would be more clearly illustrated. 
As shown, for example, in FIG. 10 a locating wall 64 is movably mounted at 
the end of each pocket 62 to close the pocket. Locating wall 64 is of 
generally U-shape so that its bight or main wall portion is disposed 
beyond the end of its respective pocket 62. When a tube 66 is inserted 
into a pocket 64 the tube 66 would be moved inwardly into its respective 
pocket until the end of the tube abuts against locating wall 64. This 
assures proper positioning of the tube for a later connect operation. Each 
lid 54 would include a pair of wall inactivating members 68 disposed for 
moving the upwardly spring biased locating wall 64 in a downward direction 
to move wall 64 clear of pocket 62 when clamp lid 54 is in its closed 
position. 
A further feature of the clamp mechanism is the provision of sensing means 
to assure the presence of a squashed tube and to assure the clamp being in 
its closed position. The details thereof are best illustrated in FIGS. 
17-20. As shown in FIGS. 18 and 20 a spring arm 70 is secured by a 
suitable fastener 72 to base clamp 52. A pin 74 is movably mounted in a 
suitable passageway in base clamp 52 and rests on spring arm 70. Pin 74 
includes an annular flange 76 which would engage the shoulder 84 in base 
clamping arm 52 to limit the upward movement of pin 74. The end of remote 
from fastener 72 carries a sensor flag 78 which is disposed for movement 
into and out of a beam from the sensor 80. When clamp lid 54 is in its 
opened position (FIGS. 17-18) spring arm 70 urges flag 70 upwardly to 
interrupt the beam thereby indicating that the clamp mechanism is open. 
Clamp lid 54 carries a tube contact tab 82. When the clamp mechanism is in 
its closed position the tube contact pad 82 would be pressed against tube 
66 and would also press against pin 74 to move pin 74 downwardly with its 
flange 76 moved away from the shoulder 84 in base clamp 52. The downward 
movement would also cause spring arm 70 to be pivoted about fastener 72 
and move flag 78 out of the beam from sensor 80, thus indicating that the 
clamp is closed and the tube is in its proper squashed condition. It is 
noted that for the sake of clarity the tube is not illustrated in FIG. 20 
but is illustrated in FIG. 19. 
After the clamp mechanisms have been loaded with tubes 6, carriage 36 is 
moved in a downstream direction when the wafer 16 has been heated to a 
predetermined temperature. 
FIG. 9 illustrates the reversible motor 86 for driving carriage 36. As 
later described motor 86 includes a magnetic encoder 87. Motor 86 rotates 
an elongated drive screw 88 to move the carriage away from its starting 
position and back to its starting position. A guide rod 90 is located 
parallel to drive screw 88 to assure proper alignment of the carriage 36 
during its movement. Carriage motor 86 may be operated by any suitable 
source such as a battery pack 92 (FIG. 2). The various mechanisms for 
turning on the heater for wafer 16, for driving motor 86 and for rotating 
arms 44 as well as the timing of the various operations may be controlled 
by a suitable controller or computer 146 as shown in FIG. 29. 
Controlled joint pivotable movement of arms 44 is accomplished by a rocker 
mechanism best illustrated in FIGS. 8 and 11. Each holder arm 44 has a 
rotatable ball or sphere 94 connected thereto. A pair of rocker arms 96 
and 98 is provided with each rocker arm having a socket 100 formed in its 
corresponding yoke. Rocker arm 96 is pivotally mounted about the smooth 
end of screw 88. Rocker arm 98 pivots about guide rod 90. Rocker arm 98 is 
the driver arm and includes a pin 104 which extends through slot 106 of 
rocker arm 96. Rocker arm 96 in turn is the driven rocker arm. 
A motor 108 controls the rotational movement of guide rod 90 which is 
associated with driver rocker arm 98. A magnetic encoder 107 is provided 
for motor 108. When the rocker arm is pivoted by guide pin 90, socket 100 
of rocker arm 98 rotates its ball 94 to rotate its arm 44 in a horizontal 
direction. Pin 104 mounted in slot 106 in turn causes driven rocker arm 96 
to rotate which in turn causes the other clamp support arm 44 to move 
horizontally in response to the seating of its ball 94 in socket 100 of 
arm 96. 
Another feature of the rocker arms is that the rocker arms may be used to 
detect that the clamp arms 44 have been moved sufficiently close to each 
other so that the tube sections are in contact with the wafer. This 
feature is best shown in FIG. 8 where the corner 110 of rocker arm 98 is 
disposed as interrupting a beam of light from a sensor 112 when the clamp 
holder arms are moved to have the tube sections in their wafer abutting 
condition. 
Downstream from the clamp mechanism is a wafer removal station 114 which 
includes a pair of copper quench blocks 111 dimensioned to permit the 
wafer 16 to be disposed between the blocks 111 when carriage 36 is moved 
to its end position. Blocks 111 are spring biased toward each other by 
being mounted to spring arms 109 to assure contacting wafer 16 to cool the 
wafer. After the wafer 16 has been sufficiently cooled it can be pulled 
upwardly from between blocks 116 disconnecting the pawl 38 from notch or 
cut-out 24. The used wafer can then be discarded. Carriage 36 would then 
be moved by drive screw 88 back to its starting position. 
One of the features of welder 10 is the inclusion of various sensors to 
assure that welder 10 is operating in its intended manner. FIGS. 1-2 and 
23-24 illustrate a sensing arrangement for assuring that the lid or cover 
12 is in its closed position. As best shown in FIG. 24 lid 12 includes a 
downwardly projecting pin 148. The upper shell 13 has an opening 150 into 
which pin 148 would enter when lid 12 is closed onto the upper shelf 
portion 13 of the casing. A photosensor 152 is mounted in opening 150. 
When pin 148 enters the opening 150 in the condition of lid 12 being fully 
closed, the beam of light from the optical sensor 152 is interrupted to 
detect the proper closure of cover or lid 12. 
As shown in FIGS. 12-14 carriage 36 has an outwardly extending arm 119 
which acts as a detector for various sensors to determine different 
conditions of welder 10. For example, sensor 13A (FIG. 14) is provided to 
indicate that the wafer 16 is properly loaded in carriage 36. Sensor 113B 
(FIG. 13) detects the wafer being properly conditioned between clenching 
block 127. 
Additional sensing is accomplished by means of spring arm 125 fixed to the 
chassis as shown in FIGS. 12-14. A flag 123 is mounted to the ends of 
spring arm 125. When flag 123 interrupts the beam from optical sensor 121 
this is a signal that there is no wafer in the carriage 136. 
The various sensors thus detect when the wafer is in the quench blocks, 
when the wafer is properly loaded and when there is no wafer in the 
carriage. Additionally, sensors detect when the carriage is in its home or 
starting position and when the carriage is in its forward most position at 
quenching station ill. 
An important feature of the invention is the provision of means to 
dissipate the aerosol that would result from the melted plastic tubes. 
This is done by the provision of negative ion generators 154 mounted to 
the inner surface of upper shell 13. Four such negative ion generators are 
illustrated. The negative ion generators 154 are interconnected by solid 
copper wires 156 and are connected by wire 158 to a pair of diodes and 
capacitors 160 associated with transformer 162. The negative ion 
generators dissolve the aerosol or gases that would form from the melted 
tubing, such as PVC material. The dissolved gases would be attracted to 
the copper wafer 16. By having a closed cover 12 dissipation of the 
aerosol is assured to maintain any smoke in the closed cavity so that the 
aerosol would be directed to the wafer 16. 
The provision of cover 12 not only functions in assuring proper operation 
of the negative ion generators and in adding to the aesthetic appearance 
of welder 10, but also covers the various components of cover 10 that 
should not be touched by the patient during operation of welder 10. Thus 
cover 12 adds to the safety in the operation of welder 10. 
A further distinctive feature of welder 10 is the inclusion of clamp pads 
164 each of which is an offset extensions of arm 166 attached to the 
bottom of each clamp lid 54. As best shown in FIGS. 25-27 and as also 
shown in FIGS. 10 and 17-19 each clamp pad 164 terminates in a serrated 
edge 168. The clamp pads 164 press against the tubes to flatten the tubes 
in a horizontal plane. When welder 10 is used for the connect procedure 
the tubes 66 are flattened to a closed condition to form a connected tube 
134 having its weld seam 136 in the plane indicated by the broken lines 
170. It is then necessary to open the tube at weld seam 136. This can be 
done by opening upper clamp 54 and rotating the flattened tube 134 about 
90.degree. so that the flattened tubes in plane 170 are now in a vertical 
rather than a horizontal orientation. The upper clamp 54 is again moved in 
the closing direction as shown in FIG. 26 and the clamp pads 164 press 
against the flat tube 134 to begin to pop the tubes open. The provision of 
the serrated edge 168 helps prevent the tube 134 from slipping back toward 
its horizontal orientation during its opening action. The opening of the 
tube joined in the connect procedure can be accomplished with the use of 
only one clamp pad although two clamp pads may be used if desired. 
The following is the sequence of operation during the tube connect 
procedure. The cycle would begin at the home or rest position where no 
tubes are in the welder 10 and no wafer is in the welder and wherein the 
clamp mechanisms are both open with the heaters off. 
A new wafer 16 would then be inserted into its holder 18 and the unit would 
be mounted into the slot 30 at the top of welder 10. The carrier would 
then be advanced all the way forward where the wafer 16 would become 
engaged with carriage 36. The holder 18 would then be moved all the way 
back and removed from welder 10. This movement strips the wafer out of the 
wafer holder and loads it onto the carriage 36. If the user does not go 
far enough the wafer would not be installed and a sensor would detect this 
condition as indicated by LED 115 (FIG. 1). If the user tries to feed 
another wafer without welding with the first wafer the carriage lock 
mechanism will prevent another wafer feed. Also if the carriage is not all 
the way back to its start position the wafer feed will be prevented. 
In a typical use a consumable would have a tube 66 attached to it. The user 
would first insert the tube into the pocket 62 in a base clamp 52. The 
tube 66 would be installed so that its end is pushed against locating wall 
64. When the clamp lid 64 is closed and locked the locating wall 64 is 
caused to swing out of the way. The user then installs the free sealed end 
of the other tube 66 coming, for example, from his peritoneum into the 
other clamp mechanism in such a manner that the sealed end of the tube 
butts against the other locating wall 64 and that wall is also moved out 
of the way when the clamped lid is closed. The start button 116 (FIG. 1) 
would then be pressed. The control unit will read this signal and begin 
the cycle. The clamp sensors would be checked to assure that the squashed 
tubes are in both clamps and that the clamp lids 54 are closed as 
previously described. 
The computer 146 operates the welder to test to see if there are two tubes 
properly loaded by trying to pull the clamp assemblies apart. If properly 
loaded this is possible to do, but if only a single tube is loaded or a 
tube spans both clamps it is not possible to pull the clamp assemblies 
apart. 
If the proper conditions are all correct the heaters are then turned on. As 
the temperature increases thermocouples mounted in the heaters monitor the 
temperature of the wafer 16 to assure that the proper temperature is 
reached. When that temperature is reached the welding cycle begins. The 
heaters are turned off and the carriage drive motor 86 is turned on to 
cause the carriage 36 to draw the wafer 16 to the melt position. The motor 
86 is then turned off and the arm motor 108 causes the tubes to touch the 
hot wafer for the first time. That time is noted and saved by the 
controller 146. The tubes 66 are driven into the sides of the wafer by the 
motor 108 at a controlled rate determined by the melt rheology. 
The carriage motor 86 is again started to again move the carriage 36 and 
its wafer 16 rapidly to the weld position in the wafer removal station 
111. At the same time the arm motor 108 will control the closure of the 
arms so that they do not attempt to form a weld until the wafer is 
completely clear of both tubes 66 at which point the tubes 66 will be 
driven together to a known final weld point. Both motors 86 and 108 then 
stop and the controller 146 begins monitoring the time to allow the weld 
to set and the spent wafer to cool. After cooling the tube clamps are 
opened and the welded tubes removed. 
The welder 10 includes various indicators to assure that the proper 
conditions are present. For example, as previously noted LED 115 indicates 
that the wafer is in its proper position. LED 118 would indicate that the 
tubes are properly loaded. LED 117 would indicate that the welder is on 
when start button 116 is pushed. LED 120 would indicate that the welder 10 
is in its connect mode when, for example, button 116 is pushed twice. LED 
122 would indicate that the welder 10 is in its disconnect mode. LED 124 
would indicate that the wafer has been heated to its proper temperature. 
FIG. 15 schematically illustrates the sequence in operation in the tube 
connect procedure. As shown therein in the first phase of operation the 
wafer 16 is mounted to carriage 36 with carriage 36 being in its start 
position. Tubes are mounted in arms 44,44 apart from each other by the 
distance indicated by the reference numeral 126. 
In the next phase of operation Carriage 36 moves wafer 16 into the gap 
between the ends of the tubes. The tubes are moved closer together by the 
distance indicated by the reference numeral 128. In this position the ends 
of tubes are under the influence of wafer 16. 
In the next phase of operation the ends of the tubes are moved sufficiently 
apart to permit the wings 20 of the wafer 16 to pass between the tubes as 
shown in the third step of FIG. 15. The tube ends are then moved toward 
wafer 116 spaced apart by the distance 130 so that the ends of the tubes 
become molten. After wafer 16 has passed beyond the tubes, 66 the tubes 
are in a condition to be pressed together and form a unitary tube 134 as 
shown in FIG. 16 with the ends welded by seam 136. By squeezing at the 
weld seam with clamp pads 164 the tube ends of the joined tube 134 become 
open and communicate with each other. 
The following describes the use of welder 10 in the disconnect procedure 
wherein reference might also be made to FIG. 21. Again the cycle begins at 
the home position with no tubes in the welder. A new wafer is installed as 
previously indicated. The user inserts a single tube 66A across both 
pockets 62 in so installing the tube, the tube 66A extends across the 
pockets and forces the locating walls 64 out of the pockets. Clamp lids 54 
are then closed and locked. 
Each press of button 116 conditions welder 10 to the next mode of 
operation. Thus, if the prior operation was the connect mode, the next 
press of button 116 puts welder in its disconnect mode. 
The start button 116 is pressed and the control unit reads the signal to 
begin the cycle. LED 122 indicates that the welder 10 is in the disconnect 
mode. The clamp sensors would be checked to assure that the tube is 
squashed and the clamp covers are closed. The user could test to see that 
there is only one tube loaded by having controller 146 try to pull the 
clamped assemblies apart. If correctly loaded it is not possible to do 
this. Only if the loading is not proper can the clamp assembly be pulled 
apart. When the loading is proper the heaters are turned on and the 
temperature monitored as previously described. At the proper temperature 
the cycle begins. The heaters are turned off and the carriage motor drive 
86 is turned on to cause the carriage 36 to draw the wafer to the cut 
position. The wafer 16 then melts its way through the tube 66A parting it 
into two sections. 
When the tubes are parted the arm motor 108 starts and causes the arms 44 
to move apart to make room for the wings 20 of the wafer to get into 
position. Once the carriage motor 86 has moved a wafer into position it is 
turned off. At this point the arm motor 108 causes the tube sections to 
move together since the hot wafer 16 is between the exposed ends of the 
tubes, however, the wings 20 of the wafer 16 plunge into the ends of the 
flattened tubes. Since the wafer 16 is still at a very high temperature on 
the order of 300.degree. C. the lumen of the exposed tube ends is fused to 
form a seal. At this point the clamp arms 44 are quickly drawn apart and 
the seals are allowed to cool. FIG. 22 illustrates the two tube sections 
138 with the end seals 140. 
The motor 86 is again started to move the carriage 36 and wafer 16 rapidly 
to the wafer removal station 114. The carriage motor 86 then stops and the 
controller begins motoring the time to allow the seal to set and the spent 
wafer 16 to cool. After cooling the tube clamps are opened and the sealed 
tubes removed. Spent wafer 16 is discarded and carriage 36 returns to its 
start location. 
FIG. 21 illustrates the condition of the arms 44 which would hold the tube 
66A and the position of the wafer 16 in carriage 36. In the initial stage 
of operation the ends of arms 44 are spaced apart by the distance 142. 
This distance is maintained while the wafer cuts through the tube 66A 
which spans arms 44,44. When the wings 20 approach the arms 44 the arms 44 
are moved apart to the distance 144 to permit the wings to enter the gap 
between the cut tube ends. The arms are then moved toward each other so 
that the wings enter the molten ends of the tube sections. Again the arms 
are moved apart and the wings become free of the tube ends so that the 
wafer can move beyond the tube ends. 
The above descriptions of the connect and disconnect procedures is fully 
automated by the use of controller or computer 146. This marks a distinct 
advancement over the present state of the art technology where manual 
operation of switches is necessary to perform connect and disconnect 
procedures. FIG. 29 illustrates a flow block diagram showing the operation 
of controller 146. Any suitable controller or computer can be used. In an 
actual practice of the invention a Micro Controller Intel 8050 Micro 440 
is used for controller 146. As shown therein the analog signals are fed to 
and from the controller 146 to control the operation of welder 10. The use 
of magnetic encoders 87 and 107 in connection with the carriage motor 86 
and arm motor 108 provides a means for determining exactly where the 
carriage and arms are at any given time. Each encoder would track the 
number of revolutions of the respective motor shaft which would be 
translated into a time and/or distance parameter for controller 146. 
Controller 146 would also function to determine if stub ends are in the 
clamp arms and if the clamp arms are in the proper spacing. For example, 
when the motor 108 is operated to move the arms to their closed position 
the arms could not be moved sufficiently close to each other if stub ends 
are inadvertently left in each arm since the stub ends would contact each 
other before the arms are moved to the closed position. 
FIG. 28 is a block diagram showing the interrelationship of controller 146 
with the various components of welder 10, including the operation of the 
arms, the carriage and the wafer. 
FIGS. 29A-C illustrate a software program which would exemplify the use of 
welder 10. In that program welder 10 is controlled by a computer program 
which consists of four main modules: 
1. ACTIVATE DEVICE 
2. CHECK DEVICE STATUS 
3. GET DEVICE READY FOR TUBE LOADING 
4. DO CONNECT OR DISCONNECT 
MODULE 1 
Activate Device 
This sets initial conditions: such as clear interrupts, turn clock ON, make 
sure negative ion generator 154 is OFF and set welder state to NOT READY 
for tube loading. It also reads the Next CYCLE information that was saved 
in memory from the last successful cycle. 
MODULE 2 
Check Device Status 
This program module handles the START push-button 116 event and checks the 
device status. Only one push-button switch (the START push-button 116) 
initiates CONNECT, DISCONNECT, CHECK-STATUS to COMMUNICATE with an 
optional external computer. This is rather unique because it eliminates 
four switches (power ON/OFF, connect, disconnect and start heat switch) 
and makes it simple to operate. Check-Device-Status program reads the 
sensors and identifies the type of tubing, if any, inserted in the device. 
If the arms 44 of the device 10 move from completely closed to completely 
open positions then the device 10 is empty (no tubing inserted) . If the 
arms 44 can not move then tube type is set to be single, solid tubing. If 
the arms 44 move and stop at a preprogrammed valid position then the tube 
type is two tubes, ready for connect. 
Module 2 also measures battery voltage and blinks the power indicator 117 
if battery voltage is too low for proper operation. 
MODULE 3 
Get-Device Ready for Tube Loading 
Initially, when power is applied, the unit is not ready for tube loading. 
First Module 3 blinks the TUBES indicator if tubing from previous 
operation was not removed. Second, Module 3 moves the wafer carriage 36 
all the way forward to wafer unload position (CLEAR WAFER routine) if a 
used wafer 16 has been detected. (See Module 3A). 
If the device is empty (no wafer and no tubes) then GET-DEVICE-READY 
routine moves the wafer carriage to home position. If CYCLE is set for 
connect then arms move to home position for connect and connect indicator 
turns ON. Otherwise, if CYCLE is set for disconnect, arms move to home 
position for disconnect and disconnect indicator turns ON. (See Module 
3B). 
MODULE 4 
Do Connect or Disconnect 
If a wafer 16 and proper type of tubing is detected when START 116 is 
pressed the program routine in Module 4 starts applying heat to the wafer 
16. When wafer 16 reaches required temperature then the device makes a 
tubing connection or a disconnection. If current CYCLE is connect and two 
tubes are detected then proper arm and carriage movements are generated by 
module 4 to make a connection. Otherwise, if current CYCLE is disconnect 
and a solid, single tube is detected the device performs arm and carriage 
movements to severe and seal the tubing. Module 4 then sets and saves the 
Next Cycle in non-volatile memory. The program always alternates next 
cycle, that is, if current CYCLE is connect then Next Cycle will be set 
for disconnect or vice versa. Module 4 also counts the number of connects 
and disconnects made and also sets EXIT true, which means the main program 
will turn power OFF to conserve the battery power. Note: The START 
push-button turns power ON. 
If the device is ready and is empty when START is pressed, that is, no 
wafer and no tube has been inserted, then program Module 4B will switch 
the current CYCLE. For example if current CYCLE is connect, CYCLE will be 
set to disconnect and arms will move to home position for disconnect.