Bellows-type Gas Meters

RITTER Bellows-type Gas Meters for measuring the volume of flowing inert and dry gases and are particularly effective at high gas flows. The major advantage of volumetric gas meters is that the volume is directly measured by the principle of displacement.

Application

Bellows-type Gas Meters are applicable for measuring the volume of flowing inert and dry gases and are particularly effective at high gas flows. Please note that gases containing aggressive components or water vapour may reduce the life span of bellows-type gas meters, if the casing of the measuring unit (tinplate), the valve/control elements (polyamide) or the bellows (Perbunan®) should be attacked. Further details on the materials that may come into contact with gases can be found under Materials.

The desired measurement range can be selected from among 6 magnitudes (types) extending together as a whole from 40 ltr/h to 160 m3/h at a gas temperature ranging from +5 °C to +40 °C. The solidly soldered casing on the standard model is designed to withstand a maximum overpressure of 50 mbar (BG 40/100: 0.5 bar).

Advantages

The major advantage and the superiority of volumetric gas meters (like bellows-type gas meters) over other measurement principles, which determine gas volume using secondary measurable variables such as speed, heat capacity, hot-wire resistance or similar, is that the volume is directly measured by the principle of displacement. That means that the condition and the composition of the gas has no influence on the measurement accuracy.

The measurement principle and the design of the measuring unit enables a measuring accuracy of ±2%.

Correcting factors which take into account gas type, temperature, humidity etc are therefore not necessary. It should be noted that with other, non-volumetric measurement processes, the measurement accuracy given for that process can only be achieved if the correcting factors for the immediate condition of the gas are exactly known. The RITTER Bellows-type Gas Meters need no maintenance and no set-up prior to the measurement. They are easy to carry, don’t need a power supply (unless equipped with option »Pulse Generator«) and can therefore used »in the field as well without problems. The measurement of temperature and pressure is necessary, if the measured and indicated actual volume of gas must be recalculated into the norm volume (as with any measurement of gas volume).

Performance Data

(1) The calibration is performed at standard flow and 20 °C (68 °F)

(2) Minimum dial division

Measurement Principle

The measurement of RITTER Bellows-type Gas Meters works on the principle of displacement. The Gas Meters contain a twin-chamber measuring unit with a flexible bellow within each chamber. Thus, a compulsory measurement of the gas flow is possible when these chambers are periodically filled and emptied. The design of the measuring chamber is such that the measuring volume per cycle of the bellows is constant. Because of the measurement principle the actual volume is measured. The movement of the bellows is caused by the pressure difference between inlet and the outlet of the meter. The periodical filling is controlled by means of two sliding valves. The oscillating movement is transformed into a rotational one and is mechanically transmitted to the counter through a magnetic coupling.

Equipment

• 8-digit Totalizing Roller Counter
• Gas Pipe Connection: Inch Thread
• Large, One-needle Dial
• Magnetic Coupling (between the measuring drum and counting mechanism)
• Twin-Chamber Measuring Unit

Materials

• Casing: BG 4 – BG 16: zinc-coated steel sheet (soldered) with outside also lacquered / BG 40 – BG 100: powder-coated steel sheet with outside also lacquered
• Measuring unit: tinplate
• Bellows (within measuring unit): textile-reinforced Perbunan
• Rod linkage: BG 4: polyamide; all others: polyamide/brass
• Slide gate: Bakelite

Built-in Options

• Pulse Generator, standard or Ex-proof version (for connecting Electronic Display Unit/Computer
• LCD Display, resettable, 8-digit (replaces Totalizing Roller Counter)

Accessories (external)

• Thermometer (BG)
• Manometer for pressure pmax = 60mbar
• Electronic Display Unit ,displays volume and calculates flow rate via RS232 and analogue-output in real time (pulse generator required)
• Nozzles for flexible tube connection