Pinch Valve Tubing
Pinch valves have no fittings. Simply slide larger tubing over small pinch
valve tube above and below the valves. The tubing in each pinch valve
can be replaced for easy cleaning. It is
1
/
32
" i.d. x
1
/
16
" o.d. silicone tubing.
We have only found one type of tubing this size which works well in these
pinch valves. AutoMate Scientific sells this replacement tubing as part
#05-14. The tubing can be removed from the valves even when they are
closed. Remember that any liquid remaining in the tube may spill when it
is removed from the valve. New tubing can be installed while the valves
are closed, but it is much easier if they are opened/energized. If you are
concerned about the same piece of tubing being squeezed for long periods
of time, you can slide the silicone tubing up or down in the valve by a
few millimeters to expose a new section to the plunger. The same piece of
tubing can be used for years without fatigue.
Valve Care
Rinse PTFE valves every day. Do not get pinch valves wet. See sections
on Faulty Valves, Stuck Pinch Valves, Valve Cables, Replacing Valves and
Leaks in the "Techniques" chapter later in this manual.
Perfusion Pencil Flow Rates
360µm Removable Tips (reservoir height 40cm)
Gravity (full reservoir) 1.15ml/min +/- .04
2psi air pressure
3.98ml/min +/- .08
8psi air pressure
10.66ml/min +/- .27
250µm Removable Tips (reservoir height 40cm)
Gravity (empty reservoir) 0.35ml/min +/- .05
Gravity (full reservoir) 0.45ml/min +/- .05
2psi air pressure
1.66ml/min +/- .14
8psi air pressure
5.16ml/min +/- .04
100µm Removable Tips (reservoir height 40cm)
Gravity 0
2psi air pressure
0.07ml/min = 4.6ml/hour
8psi air pressure
0.25ml/min = 15ml/hour
PTFE Micro-manifold Use
To use the micro-manifold, you either need pinch valves or PTFE valves
equipped with
1
/
16
" o.d. outflow hose barbs. Micro-manifolds are shipped
with a short piece of
1
/
16
" o.d. tubing in each hole (inputs and outflow).
You can either connect the valves to manifold inports with a piece of
1
/
16
"
i.d. tubing over both the valve barbs (or pinch tubing) and short pieces of
manifold tubing:
Valve with
1
/
16
" o.d. barb or pinch tubing
v
1
/
16
" i.d. tubing over barb/pinch tube
and over manifold short tubing
v
Manifold with short pieces of
1
/
16
" o.d. tubing in each port
... or, for even less dead volume, use a short piece of
1
/
16
" i.d. tubing over
the valve barb (or pinch tubing), and piece of smaller
1
/
16
" o.d. tubing
inserted inside the secondary tube and manifold ports (you may need to
supply extra small PE-160 or PTFE tubing for this option):
Valve with
1
/
16
" o.d. barb or pinch tubing
v
Short piece of
1
/
16
" i.d. tubing over valve barb/pinch
v
Small diameter
1
/
16
" o.d. tubing inserted inside valve tube
and inserted inside manifold ports
v
Manifold without connector tubing.
1
/
16
" holes.
Cutting the tubing at an angle and wetting it will make insertion easier.
Cutting the tubing square, however, will minimize dead volume when
inserted as far as possible into the manifold – being careful not block at the
point of convergence. Remember to keep all tubing as short as possible.
Use the provided Allen wrench and small screw near the manifold outflow
to adjust flow rate. AutoMate Scientific now sells small PTFE manifold
'stoppers' for plugging unused manifold ports as part #05-05 for a set of
four.
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