Drum-type Gas Meters

RITTER Drum-type Gas Meters can be used universally for measuring the volume of flowing gases, especially for small and medium flow rates, e.g. in laboratories, where the highest level of precision is required. Highest measuring accuracy of ±0.5% over the entire measuring range.

Table of Contents

User Benefits

  • Highest accuracy: ±0,5% across full flow rate range
  • Calibration traceable to the German National Primary Standard (PTB)
  • Measurement of all gases and gas mixtures with equal accuracy
  • Use with extremely corrosive and inert gases
  • Lowest measurable flow rates
  • Largest selection of measuring ranges
  • Real time data acquisition option for PC (requires option »Pulse Generator«)
  • Most durable construction – available, both chemically (from high-quality thermoplastics) and mechanically (stainless steel)
  • Maintenance-free (just checking of packing liquid level required)

Performance Specifications

Type Flow Rate
Minimum
(ltr/h)
Flow Rate
Maximum
(ltr/h)
Flow Rate
Standard
(ltr/h) (1)
Readout Indication
Minimum
(ltr) (2)
Readout Indication
Maximum
(ltr)
Measuring
Drum Volume
(ltr)
Pressure Loss
Minimum
(mbar)
TG 0.5 1 60 50 0.002 9,999,999.9 0.5 0.4
TG 1 2 120 100 0.01 99,999,999    1.0 0.2
TG 3 6 360 300 0.02 99,999,999    3.0 0.2
TG 5 10 600 500 0.02 99,999,999    5.0 0.2
TG 10 20 1,200 1,000 0.1 99,999,999    10.0 0.1
TG 20 40 4,000 3,200 0.2 999,999,990    20.0 0.1
TG 25 50 7,000 5,000 0.1 999,999,990    25.0 0.1
TG 50 100 18,000 10,000 0.5 999,999,990    50.0 0.1
(1) The calibration is performed at standard flow and 20 °C (68 °F)
(2) Minimum dial division

The maximum gas inlet overpressure is dependent on the gas meter type and casing material:
With plastic casings TG05 – TG5: Standard version 50 mbar
With plastic casings TG10 – TG50: 50 mbar
With stainless steel casings: 0.5 to 40 bar

Measuring accuracy: ± 0.2% at standard flow rate (exact value is stated in individual Calibration Certificate) and approx. ± 0.5% across the entire measuring range.

Available Models (Materials)

Material Number Casing Material Measuring Drum Material
01 Stainless steel PVC-grey
02 Stainless steel PE-el
03 Stainless steel PP-grey
04 Stainless steel PVDF
05 PVC-transparent PVC-grey
06 PP-grey PP-grey
07 PVDF PVDF
08 PE-el PE-el
Legend
PE-el =

Polyethylene-electrically conductive

PP =

Polypropylene

PVC =

Polyvinyl chloride

PVDF =

Polyvinylidene fluoride

Stainless steel =

1.4571

Viton =

Fluorine rubber

For chemical resistance properties please contact your RITTER distribution partner.

Application

RITTER Drum-type (wet-test) Gas Meters are universally applicable for measuring the volume of flowing gases and are particularly effective when measurements demand the highest precision.
The possibility of selecting the gas meter material from among 5 different excellent materials: Polyvinyl Chloride (PVC), Polypropylene (PP), Polyvinylide Fluoride (PVDF), PE-el (polyethylene electrically conductive) or refined stainless steel 1.4571 (316 Ti) enables the user individually to meet measurement requirements even in case of highly aggressive gases.
For rugged, industrial applications, robust models with a stainless steel casing and plastic drum (four different materials) are available.
The desired measurement range can be selected from among 8 sizes (types) extending as a whole from 1 Ltr/h to 18,000 Ltr/h at a gas temperature ranging from -10 °C to +80 °C. The solidly manufactured casing of the standard meters is designed to withstand a maximum overpressure of 50 mbar (plastic casings) or 500 mbar (stainless steel casings); meters for higher pressure ranges up to 40 bars are available.
The measurement of RITTER Drum-type Gas Meters works on the principle of displacement. The gas meters contain a revolving measuring mechanism (measuring drum) within a packing liquid (usual: water or low-viscosity oil). The measuring drum compulsorily measures volume by periodically filling and emptying four rigid measuring chambers.
Fastidious production methods and calibration enable a measuring accuracy of ± 0.2% at standard flow rate and approx. ± 0.5% across the entire measuring range.
The major advantage and the superiority of volumetric gas meters (like drum-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 the direct measurement of volume. That means that the condition and the composition of the gas have no influence on the measurement accuracy.
Correcting factors which take into account gas type, temperature, humidity etc are therefore not necessary. It should be noted that with other, non-volumetric measurements the accuracy given for that measurement can only be achieved if the correcting factors for the actual gas condition or gas mixture are exactly known.

Advantages

Advantages of Drum-type Meters in General

The direct measurement of volume is the major advantage and the superiority of volumetric gas meters (like drum-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. That means that the condition and the composition of the gas do not influence the measurement accuracy.

Correcting factors which take into account gas type, temperature, humidity etc are therefore not necessary. It should be noted that with other, non-volumetric measurements the accuracy given for that measurement can only be achieved if the correcting factors for the actual gas condition or gas mixture are exactly known.

The drum-type meters need no maintenance and no power supply (unless equipped with option »Pulse Generator).

Advantages of RITTER Drum-type Meters

  1. Casing and Measuring Drum out of superior plastics
    RITTER Drum-type Gas Meters are specifically designed for use with corrosive gases. They are made out of a selection of 4 superior plastics (PVC, PP, PVDF and electrically-conductive PE). A gas meter can therefore be selected which is completely resistant to the corrosive gases being measured. Stainless steel is not completely resistant to corrosive gases and will be damaged by them over time.
    Even RITTER’s Gas Meters with a stainless steel casing have a measuring drum made out of one of these high quality thermoplastics. This is because the measuring drum is the most important part of the gas meter and also the most susceptible to the effects of corrosive gases.
  2. Measuring Drum is welded – not soft soldered
    Competitor meters have a stainless steel casing and a measuring drum that is also made out of stainless steel. Because the steel plates used to make these measuring drums have to be so thin, they can only be soft soldered together. Soft solder weldings are eaten away by aggressive gases very easily! So even when the stainless steel itself is fairly resistant to corrosive gases, the soft soldering is not. This can cause the measuring drum to completely fall apart when the soft soldering is eaten away.
    The measuring drum parts in RITTER Gas Meters are welded together with exactly the same material that the drum is made out of. PVC drums are welded together with PVC rods; PP drums with PP rods, PVDF drums with PVDF rods and PE drums with PE rods. The welds in RITTER Gas Meters are therefore as corrosion-resistant as the material used to build the drums.
  3. Casing and Measuring Drum resistant against Packing Liquid – if turned into an acid
    All drum-type gas meters contain a Packing Liquid – usually water. If the measuring drum is stainless steel and is used to measure a gas which reacts with water to form an acidic solution, the acidic solution can eat through the part of the measuring drum sitting under the water-line. This occurs most rapidly in gas meters which are not used very often. RITTER Gas Meters do not have this problem.
  4. No epoxy coating needed for measuring drums
    Some gas meter manufacturers offer stainless steel measuring drums with epoxy coating. It is very difficult to apply the coating completely evenly on the drum surface, especially in the sharp corners of the drum (where the soft solder welds are). These are weak spots where corrosive gases can even more easily start to attack and destroy the drum material and soft solder welds.
  5. Magnetic Coupling instead of O-ring for drum axis

Measurement Principle

MP Phase 1

Phase 1

Chamber 1: Beginning of filling (into space above packing liquid)
Chamber 2: During filling
Chamber 3: Emptying
Chamber 4: Not active

MP Phase 2

Phase 2

Chamber 1: During filling
Chamber 2: Emptying
Chamber 3: Not active
Chamber 4: Beginning of filling (into space above packing liquid)

MP Phase 3

Phase 3

Chamber 1: Filling completed / Chamber inlet & outlet closed
Chamber 2: Emptying
Chamber 3: Not active
Chamber 4: Filling

MP Phase 4

Phase 4

Chamber 1: Emptying
Chamber 2: Emptying
Chamber 3: Filling
Chamber 4: Just beginning to fill

Standard Equipment

  • Multi-Chamber Measuring Drum
  • Magnetic coupling between measuring drum and counter (for an absolutely liquid-tight casing)
  • 8 or 9-digit Totalizing Roller Counter
  • Large One-needle Dial
  • Supports for Thermometer and Manometer
  • Viton sealing
  • Level and Levelling Feet
  • Bubble level for levelling

Accessories

Built-in Options

Accessories (external)

Packing liquids

Data-sheets