Operation Instructions

Figure: Laboratory Gasometer LG 10

Legend:

(1) pressure relief valve - bag

(2) valve for gas inlet and - outlet

(3) manometer - storage bag

(4) manometer - housing

(5) valve for pressure pipe connection (for emptying the storage bag)

(6) pressure relief valve - housing

1. Initial Operation

1.1 When delivered, the gas storage bag of the Laboratory Gasometer contains air (pressure-free). When first filling the bag, if mixing of the gas with this air is to be prevented, the storage bag must be emptied beforehand. Point 4 describes how this can be done.

If it is not necessary to previously empty the bag , the gasometer is already operational.

2. Maintenance

2.1 Before filling the bag with a gas other than that previously stored in it, it is absolutely necessary that the storage bag be “rinsed” with an inert gas. This is to avoid a possible reaction between the different gases. An explosion risk exists in particular with strongly reactive gases such as oxygen, if they mix with remnants of another gas in the storage bag

2.2 Make sure that both the storage bag and the housing are pressure-free, i.e. that both manometers do not indicate any pressure.

2.3 Open valve (2). This valve must remain opened during the filling procedure, so that the air, which is between the storage bag and the housing, can escape.

2.4 Attach the gas line to valve (1). Slowly open Valve (1) for filling.

2.5 During filling, the storage bag manometer (4) must be constantly observed in order to avoid the maximum pressure being exceeded. Maximum pressure: 30 mbar!

2.6 Close valve (1) after filling.

3. Removal of gas from the storage bag

As long as the storage bag manometer (4) indicates an overpressure, the gas can be ex-tracted by opening the gas inlet/outlet valve (1). The gas flows out under its own pressure un-til the internal pressure in the storage bag has dropped to atmospheric pressure. Once the overpressure in the storage bag has sunk to zero, more gas can be removed following the procedure described in Point 4.

4. Emptying the Gas Storage Bag

Emptying the gas storage bag is achieved by creating an overpressure in the space between the storage bag and housing wall, which squeezes the storage bag together, thus pushing the gas out of the bag. The overpressure can be created by either blowing in air or another inert gas. The following procedure should be used:

4.1 Close valve (2).

4.2 Attach an air supply line to valve (2).

4.3 Connect tubing for gas removal to valve (1) and open valve (1).

4.4 Slowly open valve (2), so that compressed air flows into the space between the storage bag and housing wall.

4.5 During filling, the housing manometer (3) must be constantly observed, in order to avoid exceeding the maximum pressure. Maximum pressure: 30 mbar!

4.6 When the storage bag can be compressed no further (no further visible movement of the storage bag), the emptying process can be terminated by closing valve (2).

Even after termination of the emptying process, gas remnants inevitably remain in the storage bag. If another gas is to be stored after this, it is absolutely necessary to “rinse” the storage bag with an inert gas, in order to avoid a possible reaction between the different gases. An explosion risk exists in particular with strongly reactive gases such as oxygen, if they mix with remnants of another gas in the storage bag!

5. Changing the foil membranes in the safety valves

(after it has been torn as a consequence of the maximum pressure being exceeded)

The safety valves of the Gas Storage Bag as well as of the Gasometer casing are fitted with a foil membrane as pre-determined breaking point in case the maximum pressure is exceeded. This is to prevent greater damage from occurring. When the maximum pressure is exceeded, the foil membrane tears and has to be replaced. Replacement occurs as follows:

• Loosen and remove the 4 safety valve screws,

• Remove the safety valve from the Gasometer, including the rubber seal.

• Remove the torn foil membrane [located between the seal and the head of the safety valve (= cylindrical, grey PVC part, to which the fastening screws attach)],

• Place the new foil membrane between the seal and the head of the safety valve,

• (It is advantageous to lightly pierce the foil membrane through the holes of the seal with a sharp object such as a needle or sharp pencil, in order to prevent the foil from tearing when the 4 fastening screws are inserted.)

• Insert the 4 fastening screws into the head of the safety valve: the screws go through the holes in the head of the valve, through the foil membrane and through the seal. At the same time, press the seal against the head of the valve in order to prevent the foil from moving,

• Fasten the safety valve to the Gasometer casing using the 4 fastening screws.

Subject to alterations