Application 

The RITTER Bellows-Type Gas Meter is applicable for measuring the volume of flowing inert and dry gases and is particularly effective for high gas flows. 

Gases containing aggressive components or water vapor may shorten the service life of bellows-type gas meters if they attack the casing of the measurement device (tinplate), the valves/control elements (polyamide), or the bellows (Perbunan®), which must be protected. Detailed information on materials that may come into contact with the gas can be found under »Materials«.

The desired measurement range can be selected from six sizes (types) ranging from 40 ltr/h to 160 m³/h overall, at gas temperatures ranging from -20 °C to +50 °C. 

The robustly soldered casing of the standard model is designed to withstand overpressure up to 50 mbar (BG 40/100: 0.5 bar).

Advantages 

The main advantage and superiority of volumetric gas meters (e.g., bellows-type gas meters) compared to other measurement principles that determine gas volume using secondary measurable variables such as velocity, heat capacity, and hot wire resistance is that volume is directly measured by the displacement principle. This means that the state and composition of the gas do not affect measurement accuracy.

Due to the measurement principle and the design of the measurement device, a measurement accuracy of ±2% is achievable.

Therefore, correction factors considering gas type, temperature, humidity, etc. are not required. 

For other non-volumetric measurement processes, it should be noted that the measurement accuracy provided for that process can only be achieved when the correction factors for the immediate state of the gas are precisely known. 

The RITTER Bellows-Type Gas Meter does not require maintenance or setup prior to measurement. It is easy to transport, does not require a power supply (unless the optional »Pulse Generator« is installed), and can therefore be used without issue even »in the field.«

If the actual measured and displayed gas volume needs to be recalculated to standard volume (as with gas volume measurement), temperature and pressure measurements are required.

Advantages 

(1) Calibration is performed at standard flow rate and 20°C (68°F). (2) Minimum dial division

Measurement accuracy: ±2% at standard flow rate and 20°C (exact value specified in the individual calibration certificate), temperature range: -20°C to +50°C. Reverse flow is not possible!

Measurement Principle 

The measurement of RITTER Bellows-Type Gas Meters operates on the displacement principle. The gas meter contains a twin-chamber measurement device with a flexible bellows within each chamber. 

Therefore, by periodically filling and emptying these chambers, it is possible to forcibly measure gas flow.

The design of the measurement chambers is configured so that the measurement volume per cycle of the bellows is constant. Due to the measurement principle, the actual volume is measured. 

The movement of the bellows is caused by the pressure difference between the meter inlet and outlet. Periodic filling is controlled through two sliding valves. The oscillating motion is converted into rotary motion and mechanically transmitted to the counter via magnetic coupling.

• Outer casing of the measurement device: Material: Galvanized steel sheet (soldered); the exterior is also lacquered.
• Identical twin-chamber case of the meter. Material: Tinplate sheet
• Inflexible part of the membrane. Material: Tinplate sheet. Flexible part of the membrane.
• Material: Fiber-reinforced nitrile rubber (Perbunan).
• Gas inflow into the chamber.
• Gas outlet

Standard Equipment 

• Twin-chamber measurement device
• 8-digit or 9-digit totalizing roller counter
• Large single-needle dial
• Magnetic coupling (between measurement drum and counting mechanism)
• Gas pipe connection (inch thread)

Materials 

1. BG 4 – BG 16: Zinc-coated steel sheet (soldered) with outside also lacquered
2. 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 

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

Accessories (external) aterials 

• Thermometer (BG)
• Manometer for pressure pmax = 60 mbar
• Electronic Display Unit »EDU 32 FP«, displays volume and calculates flow rate via RS232 and analog-output in realtime (pulse generator required)
• Nozzles for flexible tube connection