SKC 303 Film Flowmeter User Manual
Soap film flowmeter cat. no. 303, Operating instructions
Soap Film Flowmeter
Cat. No. 303
SKC primary standard fl owmeters are designed, manufactured, and tested for accuracy; no calibration
is needed. Read the operating instructions thoroughly before operating the fl owmeter.
Principle of Operation
The air sampling pump to be calibrated is connected to and pulls air through the fl owme-
ter’s volumetric glass tube where a fl at soap bubble (fi lm) is interposed into the fl ow path.
As the airfl ow causes the fi lm to move up the volume marks, travel time is measured using
a stopwatch. Flow rate can be calculated using the travel time and known tube volume. The
303 Portable Flowmeter Kit is calibrated to a primary standard ± 2% of the volumes marked
on the fl owmeter.
Assembly
SKC Model 303 is shipped ready to use. Film solution is supplied as well as a length of rubber
tubing to connect the fl owmeter to the pump.
Preparing for Operation
1. Remove the fl owmeter from the case, and place it upright on a level surface.
2. Remove the large rubber stopper from the top of the fl owmeter.
3. Tip the fl owmeter at an angle, and pour a small amount of fi lm solution into the top of
the glass tube. The liquid should run down into the rubber bulb at the bott om.
4. Continue adding fi lm solution until it completely fi lls the bulb and rises to just below
the side arm inlet. Squeeze the rubber bulb occasionally to release trapped air.
5. Replace the stopper on top of the fl owmeter.
Wetting the Walls of the Tube
The interior walls of the fl owmeter must be wet for the fi lm to travel without rupture. There
are two methods:
Method 1
1. Tip the fl owmeter to a horizontal position. Allow the fi lm solution to run out of the rub-
ber bulb and into the tube.
2. Maintaining the horizontal position, rotate the fl owmeter so that fi lm solution coats the
entire inside surface of the glass. Caution: Do not allow the solution to enter the metal
tube in the rubber stopper at the top of the fl owmeter.
3. Return the fl owmeter to an upright position and allow the liquid to fl ow back down
into the rubber bulb. Squeeze the bulb occasionally to release trapped air.
Method 2
1. Connect a pump to the fl owmeter (see Connecting a Pump).
2. Turn on the pump. Each successive fi lm that rises up the tube will wet the glass. The
walls are suffi
ciently wet when the fi lm bubbles successfully reach the highest volume
mark on the fl owmeter.
Operating Instructions
863 Valley View Road, Eighty Four, PA 15330 USA