RITTER Gas Meters (Drum-Type, Bellows-Type)
Drum-type Gas Meters TG-Series (Wet-Test)
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: 50 to 500 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.
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
- 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. - 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. - 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. - 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. - Magnetic Coupling instead of O-ring for drum axis
Competitor stainless steel gas meters have an axis which must go through the casing wall to connect the measuring drum to the needle indicator on the gas meter dial face. These meters have an O-ring or similar to seal the hole in the casing where the axis goes through. This O-Ring is under the packing liquid level. Because of the mechanical friction of the axis turning in the O-Ring, the O-Ring eventually begins to wear out.
If a gas has reacted with the packing liquid and turned it acidic, this acidic solution also begins to eat into the O-Ring material. Sooner or later the O-ring starts leaking. This causes the level of the packing liquid to drop. This drop in packing liquid level causes the gas meter to measure inaccurately. At first, when leakage is small, the drop in packing liquid level may not be realised by the user, so he/she does not realise that the measurement is wrong. If this leak becomes greater, the acidic packing liquid which leaks into the counter mechanism casing can damage the parts there.
RITTER uses a magnetic coupling system to connect the measuring drum to the needle indicator on the gas meter dial face. This means that there is no hole in the casing wall, and no O-Ring. The casing wall remains solid, and so there is no possibility of packing liquid leaking out. The gas meter remains gas and liquid-tight for its lifetime. - Transparent casing with PVC Gas Meters
If dirty gases are measured, the rotation of a drum-type gas meter measuring drum acts like a washing machine and forces the »dirt« out of the gas. This sediment builds up on the bottom of the gas meter casing. If it builds up too much it can hit the measuring drum, either slowing it down or making it stop altogether. If it slows it down, the measuring accuracy is affected without the user knowing. If it stops the rotation of the drum, it ruins that test run completely. With stainless steel gas meters, the user cannot check how much sediment has built up on the bottom of the gas meter casing and so does not know if the test runs are being affected.
RITTER PVC Gas Meters have a transparent casing, which means that this sediment build-up can be very easily monitored. The gas meter can be taken off-line before the sediment build-up can affect measurement accuracy or ruin test runs. It can then be cleaned between runs. - RITTER Meters can be repaired
If a stainless steel gas meter has been epoxy-coated, it is very difficult, if not impossible, to repair. This is because epoxy-coated parts cannot be re-welded. Because of this, some stainless steel gas meter manufacturers refuse to repair these meters. When they do repair, these repairs can be very expensive. This is because undamaged epoxy-coated parts have to sometimes be removed to get to the damaged parts in the meter. Because the undamaged epoxy-coated parts cannot be re-welded, they have to be replaced along with the damaged parts.
The thermoplastics which RITTER uses to build gas meters can be re-welded. That means that only the truly damaged parts need to be replaced. This makes RITTER repairs economical.
Measurement Principle
![]() | Phase 1: Chamber 1: Beginning of filling (into space above packing liquid) Chamber 2: During filling |
![]() | Phase 2: Chamber 1: During filling Chamber 2: Emptying |
![]() | Phase 3: Chamber 1: Filling completed / Chamber inlet & outlet closed Chamber 2: Emptying |
![]() | Phase 4: Chamber 1: Emptying Chamber 2: Emptying |
Equipment
- 8-digit Totalizing Roller Counter
- Bubble level for levelling
- Level and Levelling Feet
- Magnetic Coupling (between the measuring drum and counting mechanism) , for an absolutely liquid-tight casing
- Multi-Chamber Measuring Drum
- Supports for Thermometer and Manometer
- Viton sealing
Accessories
Pulse Generator , standard or Ex-proof version (for connecting Electronic Display Unit/Computer)
Accessories (external)
Features
- Windows software for data acquisition of gas volume and flow rate from up to 24 RITTER Gas Meters to a PC USB port.
- Support of multi-core processors
- Graphical and tabular display of measurement data
- Storing of data
- Print out (separately or in any combination) of Diagram / Test parameters / Measured values in tabular form
- Export of stored data to Microsoft Excel® spread-sheet (Excel 2003 or higher)
- Automatic correction of the dynamic (flow rate dependent) measurement error (MGC only)
Please note: »RIGAMO« can only started once at a time on a single PC.
No support of bi-directional recognition of the measuring drum rotation with Pulse Generator V4.01
Interface
Main Window (Data Window)
- Area 1: Display of port status
- Area 2: Tabular display of data for respective ports in real time
- Area 3: Tick boxes for display »show« / »no show« of graphs
- Area 4: Indicator for online / offline display of graphs
- Area 5: Diagrams for gas volume and flow rate
- Area 6: Indicator of processor load status and »DIM« connection status
- Area 7: Buttons »Start/Stop« of data acquisition
- Area 8: Menu item “Diagram” for displaying diagram related settings
Diagram Settings
- Area 1: Selection of graph updating mode (automatically/manually)
- Area 2: Number of last measurement data to show in diagram
- Area 3: Dimensions of diagram axes
Please note: The illustrations shown above represent Rigamo Software V 3.2 Beta. The user interface of previous versions may differ. For further information, please refer to the documentation provided with the software.
System Requirements
- Gas meter with built-in pulse generator (MilliGascounter standard)
- Digital Input Module »DIM« (option)
- Licence (dongle) for requested number of connected gas meters
- Operating system: Windows® XP / Vista / 7 / 8 / 10
- Microsoft Excel® 2003 or higher for data export to Excel®
- Recommended processor performance: ≥1.5 GHz
- Random access memory (RAM): ≥500 MB
- 2 free USB ports (1 port for data acquisition, 1 port for licence dongle)
- Monitor 17’’ (optimised for monitor resolution of 1280x 1024 pixel or higher)
Please note: No other National Instruments software should be installed on the respective computer as it may conflict with the RIGAMO software.
A standard converter »USB to RS232« for connection to COM port cannot be used.
Display Example
E. g. data acquisition from 3 gas meters; red graphs: volume; blue graphs: flow rates
Data Export to Excel
System requirement: Microsoft Excel® 2003 or a later version
Export example of four data files:
The data of each data file (parameters plus measurement data) are exported into a separate table. Additionally, a blank table is created with the name of the export file (see red mark in the window above).
Configuration Example
Schematic of a completed configuration of RITTER Gas Meter, Digital Input Module, PC and Rigamo (Example for connection of 4 gas meters)
Thermometer Gas (TG)
Suitable for: RITTER Drum-type Gas Meters
Filling liquid: Isoamylbenzoat »IAB«
Measuring Range
0 °C | to + 60 °C, | scale graduation 0.5 °C |
0 °C | to + 80 °C | scale graduation 0.5 °C |
15 °C | to + 30 °C | scale graduation 0.1 °C |
0 °C | to + 50 °C | scale graduation 0.1 °C |

Application
The Thermometer can be used for measurement of the gas temperature while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure. The norm volume of a gas is the volume at norm conditions which are (in Germany).
The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm Temperatur | = 273,15 Kelvin ( = 0 °C) |
Norm Druck | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
![]() |
Installation
Unpack the Thermometer. Unscrew the closing cap of the Thermometer (Gas) support on the Gas Meter. Mount the Thermometer by inserting it carefully through the Thermometer (Gas) support. Seal the Gas Meter’s casing by tightly screwing the union nut which is attached to the Thermometer. Thus, the Thermometer is ready for use. The removed closing cap of the support can be stored easily by screwing it onto the respective thread support located at the base plate of the gas meter.
Thermometer Gas (TG) Datasheet
Thermometer Packing Liquid (TG)
Filling liquid: Isoamylbenzoat »IAB«
Measuring Range
0 °C | to + 60 °C | scale graduation 0.5 °C | |
0 °C | to+ 80 °C | scale graduation 0.5 °C | |
15 °C | to + 30 °C | scale graduation 0.1 °C | |
0 °C | to + 50 °C | scale graduation 0.1 °C |

Application
The Thermometer (Packing Liquid) can be used for measurement of the Packing Liquid temperature while measuring the gas flow.
According to the rules for calibration and measurement with Drum-type Gas Meters, the temperature of the Packing Liquid may vary from the gas temperature by up to 0.5 °C at most. A greater temperature deviation would cause too great a change to the gas temperature when the gas comes unavoidably into contact with the Packing Liquid during measurement. This temperature change would cause an unknown change in the volume of the measured gas which might lead to a measurement/indication error.
Installation
Unpack the Thermometer. Unscrew the closing cap of the Thermometer (Packing Liquid) support on the Gas Meter. Mount the Thermometer by inserting it carefully through the Thermometer (Packing Liquid) support. Seal the Gas Meter’s housing by tightly screwing the union nut which is attached to the Thermometer. Thus, the Thermometer is ready for use. The removed closing cap of the support can be stored easily by screwing it onto the respective thread support located at the base plate of the gas meter.
Manometer for pressure pmax ≤ 50 mbar
Type | Wide-scale Manometer | |||
Measuring Range (over- / underpressure) | 0 to 10 mbar | 0 to 20 mbar | 0 to 40 mbar | 0 to 50 mbar |
Resolution | 0.1 mbar | 0.1 mbar | 0.1 mbar | 0.1 mbar |
Dimensions | 190 x 40 x 15 mm | 305 x 40 x 15 mm | 540 x 40 x 15 mm | 650 x 40 x 15 mm |
Weight | 0.30 kg | 0.40 kg | 0.62 kg | 0.72 kg |
Material: PMMA

Application
The Manometer for pressure pmax ≤ 50 mbar can be used for measurement of the gas pressure while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure.
The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm Temperatur | = 273,15 Kelvin ( = 0 °C) |
Norm Druck | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
![]() |
Note: The indicated gas pressure at the manometer is the differential pressure between the gas pressure at the gas inlet and the actual atmospheric air pressure. Thus, the actual gas pressure (pa) to use in the above formula is the indicated gas pressure at the manometer plus the actual atmospheric air pressure in [mbar].
Installation
Unpack the Manometer. Mount the Manometer into the Manometer support. Unscrew the closing cap of the »Manometer Connection« port located at the »Gas Inlet« nozzle at the center of the rear plate. The removed closing cap of the port can be stored easily by screwing it onto the respective thread support at the rear side of the Manometer. Screw the closing cap, which is attached to the flexible Manometer pipe, tight to the »Manometer Connection« port.
Filling the Manometer
The Manometer is to be filled with the red Special-Equipment Filling Oil (»Spezial-Gerätefüllöl«) provided with the Manometer. First remove the white thumb screw from the Filling Hole. Pour in the Oil until the Oil column reaches the »0«-mark on the front of the Manometer. Replace the white thumb screw. Please note: Only the specially provided red oil should be used with this Manometer (Density 0.88)! If the manometer is filled with an oil with a different density, the Manometer indication will inevitably be wrong.
Then, unscrew the closing cap of the »Manometer Connection« port located at the Gas Inlet nozzle (on the rear side of the Gas Meter casing). The removed closing cap of the port can be stored easily by screwing it onto the thread support on the rear of the Manometer. Lastly, tightly screw the closing cap attached to the flexible Manometer tube, onto the »Manometer Connection« port. The Manometer is then ready for use.
Reading the Manometer
The oil column of the Manometer indicates the differential pressure in [mbar] of the gas between the Gas Inlet of the Gas Meter and the atmospheric pressure.
Caution: If the Manometer is connected to the gas inlet of the Gas Meter but not filled with oil, gas will leak through the Manometer. This will inevitably cause a measurement error of the Gas Meter.
Manometer for pressure pmax ≤ 1 bar
Type | Capsule pressure gauge | ||
Measuring Range | 0 to 600 mbar | 0 to 1 bar | |
Resolution | 20 mbar | 50 mbar |
Material: Stainless steel (Cr-Ni)
Application
The Manometer can be used for measurement of the gas pressure while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure.

The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm temperature | = 273,15 Kelvin ( = 0 °C) |
Norm pressure | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
VN | = | Norm Volume in | [ltr] |
Vi | = | indicated Volumen in | [ltr] |
pN | = | Norm Pressure in | [mbar-absolut] |
pa | = | actual Pressure in | [mbar-absolut] |
TN | = | Norm Temperature in | [Kelvin] |
Ti | = | indicated Temperature in | [Kelvin] |
Note: The indicated gas pressure at the manometer is the differential pressure between the gas pressure at the gas inlet and the actual atmospheric air pressure. Thus, the actual gas pressure (pa) of the above formula equals the indicated gas pressure at the Manometer plus the actual atmospheric air pressure in [mbar].
Installation
The Manometer is pre-mounted to the gas meter (positioned at the gas inlet nozzle). The gas inlet nozzle is labelled accordingly. Therefore, the manometer is ready for use and no further installation is to be performed by the user.
Please note: The manometer screw connection to the gas meter is sealed by Teflon® tape. When disassembling the manometer from the gas meter, the Teflon® tape cannot be used again and must be replaced by a new Teflon® tape.
Manometer for pressure pmax ≤ 10 bar
Type | Bourdon tube pressure gauge | ||
Measuring Range | 0 to 6 bar | 0 to 10 bar | available for higher pressure ranges |
Resolution | 0.2 bar | 0.5 bar |
Material: Stainless steel (Cr-Ni)
Application
The Manometer can be used for measurement of the gas pressure while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure.

The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm temperature | = 273,15 Kelvin ( = 0 °C) |
Norm pressure | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
VN | = | Norm Volume in | [ltr] |
Vi | = | indicated Volumen in | [ltr] |
pN | = | Norm Pressure in | [mbar-absolut] |
pa | = | actual Pressure in | [mbar-absolut] |
TN | = | Norm Temperature in | [Kelvin] |
Ti | = | indicated Temperature in | [Kelvin] |
Note: The indicated gas pressure at the manometer is the differential pressure between the gas pressure at the gas inlet and the actual atmospheric air pressure. Thus, the actual gas pressure (pa) of the above formula equals the indicated gas pressure at the Manometer plus the actual atmospheric air pressure in [mbar].
Installation
The Manometer is pre-mounted to the gas meter (positioned at the gas inlet nozzle). The gas inlet nozzle is labelled accordingly. Therefore, the manometer is ready for use and no further installation is to be performed by the user.
Please note: The manometer screw connection to the gas meter is sealed by Teflon® tape. When disassembling the manometer from the gas meter, the Teflon® tape cannot be used again and must be replaced by a new Teflon® tape.
Electronic Display Unit »EDU 32 FP«
General Overview
Application
The EDU 32 FP accessory is a microcomputer-controlled counter and display apparatus. It is designed to be used in conjunction with RITTER Gas Meters, to count and display the abso-lute volume and flow-rate of Gases flowing through the RITTER Meter. It consists of a unit in a separate (desk top) casing with a two-line Plain-Text-LCD-Display, and can be used with all types of RITTER Gas Meters. The following individual alterations and functions can be programmed via the Control Buttons:
- Gas Meter type being used
- Individual measurement range (min./max. flow rates) for custom-built Gas Meters
- Upper and lower limiting values for Flow Rate
- Pulse Generator in use: Standard (200 Pulses per revolution of the measurement drum), Ex-Proof (50 Pulses/Revolution) or custom-built Models (customer-preferred number of pulses under 200 or 50 respectively)
- Language German/English in the Display
- Analog-Output: Current Output or Voltage Output
- Contrast adjustment of the Display
Technical Data
Power supply
- either 110 V / 60 Hz or 230 V / 50 Hz (must be specified with order)
- Over-/undervoltage:
- +15%
- -5% (with Current Output “On”)
- -20% (with Current Output “Off”)
- 6 Volt Accumulator for battery operation
- Standart power socket, power cord (1)
Input
Pulses from Pulse Generator built into Gas Meter, round 5-pin-socket suitable for all RITTER Drum-type Gas Meters and Bellows-type Gas Meters (Type and Model programmable via the control buttons).
Output
- Interface RS 232 (Standard Sub-D-9-pin-socket):
- Signal: +/- 15 Volts
- Transmission rate: 9,600 Baud
- Data = 8 Bit, Parity = N, Stopbit = 1
- Analog Output, programmable, round 5-pin-socket:
- Current Output: 4 – 20 mA or 0 – 20 mA or
- Voltage Output : 0 – 1 Volt
Display
- large 2-line LCD Display, 16 characters per line
- Display language programmable: English / German
- Display contrast adjustable (via the Menu)
- Display of:
- measured Gas Volume in [Liters]
- actual Flow Rate in [Liters per hour]
- programmed Gas Meter type/model
- power status (Mains / Battery / Low Batt)
Control elements
- Push-buttons, waterproof
Button | Function |
ON/OFF | On/Off |
RESET | (in measurement Mode): Resetting the Display to zero |
ENTER | (in set-up mode): For scrolling through provided Menu Options and saving of selected option |
MODE | (in measurement Mode): Choice of Display “Volume” and/or “Flow Rate” |
SELECT | (in set-up mode): For selection of required Menu Option |
Further Functions
- Data transmission via RS 232 to a PC
- Configuration of the EDU 32 FP from the PC
- Pre-selection of a minimal or maximal Flow Rate
- Acoustic Signalling (Beep) when the Flow Rate values exceed the pre-selected min./max. range
- Power supply for the power interface can be turned off (to in-crease the running time during battery operation)
Control Codes
(for data transmission from Interface RS 232 to Computer)
- Ctrl-V (Hex 16) provides: VOL 00000,00 LTR
- Ctrl-F (Hex 06) provides: FLOW 000,00 L/H
- Ctrl-C (Hex 03) causes: RESET
- Ctrl-T (Hex 14) provides: Type + Power Status
Fuse
- 0.1 Ampere – located at the rear wall in a fuse drawer below the power socket. The fuse drawer contains a spare fuse as well.
Dimensions
- Width x depth x height = 155 x 200 x 120 mm
Weight
- 1,4 kg
Temperature Range
- 0 °C to + 50 °C
Scope of supply
- Power cord (with delivery into countries with German Standard for socket / plug only)
- Connection cord to Pulse Generator
Packing liquids
HCl solution 1.8 vol% for gas mixtures with CO2
Pionier 4281
General
Pionier 4281 is a medical paraffinic mineral White Oil containing aromates in trace elements. It is colourless, odourless, and clear.
Safety instructions
- Swallowing and inhalation:
Can be fatal after swallowing and intrusion into respiratory system. When swallowing the product may be absorbed in the lungs due to its low viscosity and lead within a short time to develop serious lung damage. (The patient must be monitored medically for 48 h.) Immediately contact local or national Poison Information Center (Germany: +49-551-19240) or doctor! Don’t effect vomiting! - For further information refer to the Material Safety Data Sheet.
- Disposal according to governmental regulations.
- No dangerous good in terms of transport regulations.
Application
Pionier 4281 can be used with RITTER Drum-type Gas Meters made out of PVC, PVDF and Stainless Steel.
Incompatible substances
- Not suitable for measurements with oxygen.
- Contact with strong oxidising agents (e.g. peroxides, chromates) can lead to fire hazard.
- Mixing with nitrates or other oxidising agents (e.g. chlorates, perchlorates, liquid oxygen) can create an explosive compound.
Advantages
- Use under 0°C.
- Less evaporation than water due to its lower vapour pressure.
- Greater stability of the Packing Fluid level.
- Improvement in the repeatability of measurement results.
- Reduction in the required frequency of Packing Fluid level monitoring.
- The gas remains dry.
- In general, a lower chemical reactivity with water.
Solubility of gases
No data available from manufacturer.
Properties
Viscosity: | 20 | °C | 6.5 | cSt (=mm2/sec) |
40 | °C | 4.0 | cSt | |
Density: | 15 | °C | 0.81 | g/ml |
Vapour pressure: | 20 | °C | < 0.1 | mbar |
Pour point: | -9 | °C | ||
Flashpoint: | 115 | °C | ||
Thermal expansion coefficient: | 0.0007 | K-1 | ||
Appearance: | Colourless, odourless, and clear |
Silox
General
Silox is a synthetic oil belonging to the group of polydimethyl siloxane. It is colourless and clear with a weak odour.
Application
Silox can be used in all RITTER Drum-type Gas Meters. As opposed to water as a Packing Fluid, Silox can be used under 0°C. It also has a lower evaporation rate in combination with a viscosity similar to water. Because of this, the Packing Liquid level remains stable over a longer period of time. This leads to an improvement in the repeatability of measurement results, and in a reduction in the required frequency of Packing Liquid level monitoring.
The use of Silox is further recommended when the gas should remain dry or when the gas reacts with water.
Not suitable for wet chlorine gas and alkanes (methane, ethane, butane, pentanes).
Advantages
- Use under 0°C (down to -40°C)
- less evaporation than water due to its lower vapour pressure, resulting in greater stability of the Packing Fluid level and in more consistent measurement result
- the gas remains dry
- in general, a lower chemical reactivity than water
Properties
Viscosity: | 20 | °C | 4 | cSt (=mm2/sec) | ||
25 | °C | 4 | cSt | |||
Density: | 15 | °C | 0.96 | g/ml | ||
25 | °C | 0.95 | g/ml | |||
50 | °C | 0.93 | g/ml | |||
Vapour pressure: | 20 | °C | 0.16 | mbar | ||
50 | °C | 38 | mbar | |||
Boiling Point: | 205 | °C | ||||
Pour point: | -40 | °C | ||||
Flash point: | 70 | °C | ||||
Ignition point: | 450 | °C | ||||
Appearance: | Clear, odourless, colourless fluid |
CalRiX
General
CalRiX is a completely synthetic fluid on a fluorine base. It is of low molecular weight, colourless, clear and odourless.
More detailed information about the chemical composition and molecular structure of this fluid can be obtained upon request.
Application
CalRiX can be used with all RITTER Drum-type Gas Meters (Wet-type Gas Meters). Because CalRiX is completely inert to most gases including oxygen, it can be used as a Packing Fluid when water or paraffin oil are not suitable. For example, when the gas needs to remain dry, and when the gas is highly reactive to water or paraffin oil. It is appropriate for use with such gases as:
- Butane
- Carbon Dioxide
- Carbon Tetrachloride
- Carbon Tetrafluoride
- Chlorine
- Deuterium
- Fluorine
- Helium
- Hydrogen chloride
- Hydrogen Fluoride
- Methane
- Nitrogen trichloride
- Nitrogen trifluoride NF3
- Oxygen
- Phosphine
- Propane
- Silane
- Sulphur Hexafluoride
Advantages
- Extremely resistant even against highly aggressive gases because of CalRiX’s fluorine base,
- less evaporation than water due to its lower vapour pressure, resulting in greater stability of the Packing Fluid level and in more consistent measurement result,
- very smooth rotation of the measuring drum in the Gas Meter because of CalRiX’s high density and low surface tension.
Properties
Viscosity: | -20 | °C | 11,7 | mm2/sec (= cSt) |
20 | °C | 2,7 | mm2/sec | |
25 | °C | 2,4 | mm2/sec | |
100 | °C | 0,7 | mm2/sec | |
Density: | 20 | °C | 1,80 | g/ml |
100 | °C | 1,64 | g/ml | |
Vapour pressure: | 20 | °C | 0,4 | mbar |
100 | °C | 30,8 | mbar | |
120 | °C | 65,6 | mbar | |
Working Temp. Range: | -20 | °C | to 190 | °C |
Boiling Point:: | 200 | °C | ||
Pour point: | -85 | °C | ||
Solubility of Water: | 14 | ppm | ||
Solubility of Air: | 26 | cm3 gas per 100 cm3 liquid | ||
Volatility: | 34.4 | % in 22 Stunden bei 66°C | ||
Appearance: | Clear, odourless, colourless fluid |
Solubility of Gases (Bunsen coefficient at room temperature)
Butane | 8.5 |
Boron Trichloride | 13.1 |
Boron Trifluoride | 0.22 |
Carbon Dioxide | 1.2 |
Carbon Tetrachloride | 52.6 |
Carbon Tetrafluoride | 0.68 |
CFC 114 | 14.9 |
CFC 12 | 4.25 |
CFC 133a | 13.9 |
CFC 134a | 4.7 |
CFC 21 | 13.1 |
CFC 22 | 4.86 |
Chlorine | 3.19 |
Deuterium | 0.10 |
Esafluoroethane | 2.12 |
Fluorine | 0.20 |
Helium | 0.08 |
Hydrochloric acid | 0.806 |
Hydrogen | 0.10 |
Methane | 0.17 |
Nitrogen | 0.19 |
Nitrogen Trichloride | 0.83 |
Nitrogen Trifluoride approx. | 0.9 |
Oxygen | 0.29 |
Phosphine | 0.67 |
Propane | 3.8 |
Silane | 0.36 |
Sulphur Hexafluoride | 3.5 |
The Bunsen coefficient [N ml/ml] is the volume of gas, reduced to Normal condition (1013 mbar, 0°C), dissolved in the volume unit of fluid.
Bellows-type Gas Meters BG-Series (Dry-Type)
Application
RITTER 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 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.
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).
Performance Data
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] (2) | Maximum gas inlet pressure [mbar] |
---|---|---|---|---|---|---|
BG 4 | 40 | 6,000 | 3,000 | 0.1 | 99,999,999 | 300 |
BG 6 | 60 | 10,000 | 5,000 | 0.2 | 99,999,999 | 300 |
BG 10 | 100 | 16,000 | 10,000 | 0.5 | 999,999,990 | 50 |
BG 16 | 160 | 25,000 | 15,000 | 0.4 | 999,999,990 | 50 |
BG 40 | 400 | 65,000 | 39,000 | 0.4 | 999,999,990 | 500 |
BG 100 | 1,000 | 160,000 | 95,000 | 0.4 | 999,999,990 | 500 |
(1) The calibration is performed at standard flow and 20 °C (68 °F)
(2) Minimum dial division
Measuring accuracy: +/- 2% at standard flow and 20 °C (exact value is stated in individual Calibration Certificate)
Temperature range: +5 °C to +40 °C
No reverse flow direction possible!
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 (1). 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.
(1) 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).
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.
Legend
- Outer casing of the meter: Material: Zinc-coated steel sheet (soldered) with outside also lacquered.
- Casing of the identical twin chambers of the Meter. Material: Tinplate
- Non-flexible part of membrane. Material: Tinplate sheets
- Flexible part of membrane. Material: Textile-reinforced nitrile rubber (Perbunan).
- Gas entry to the chamber.
- Gas outlet
Equipment
- 8-digit Totalizing Roller Counter
- Gas Pipe Connection: Inch Thread
- 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
Accessories
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)
LCD Display
Suitable for: | RITTER drum-type and bellows-type gas meters (not for TG01) |
Indication: |
|
Resolution: | = volume of measuring drum |
Application
The resettable LCD counter displays the volume measured by the gas meter. As an option it is available for RITTER drum-type and bellows-type gas meters and must be ordered along with the gas meter.
Use in ex-proof areas
The LCD counter is not intrinsically safe. Therefore, it cannot be used in ex-proof areas in general! For exceptions please check with your authorized ex-proof safety representative .
Functional principle
A permanent magnet as well as a reed contact are mounted within the counter casing of the gas meter. The permanent magnet closes the reed contact once per revolution of the measuring drum of the gas meter. Each pulse of the reed contact adds a volume increment to the displayed volume. The volume increment equals the measuring drum volume of the respective gas meter. Fractions of a drum revolution are indicted by the dial face indicator (needle).
The LCD display is battery operated.
Please note:
- If the direction of drum rotation is reversed (by under-pressure at the gas inlet or over-pressure at the gas outlet), the pulses of the reed contact are detected by the counter. Subsequently, the respective »negative« gas volume is wrongly added because a detection of the rotational direction of the drum is not possible with the red contact.
- Prior to resetting the counter to »zero«, the indication needle must be turned to »zero« as well. Because the indication needle is coupled to the drum via the shaft and magnetic coupling, the gas meter must be depressurised (gas inlet/outlet open). Thus, the drum can rotate without resistance and the indicator needle can be reset to »zero« easily.
Technical data
- Battery life time approx. approx. 5 years
- Reset manual reset via pushbutton, (can be locked)
- Reset lock via bridge between terminals »Keylock« and »0 V«
- Operating temperature -10 .. +50°C
- Display 8-digit LCD, 7 mm
- Supply voltage internal lithium battery
- Protection class (IEC 144) front side IP 65, terminals IP 20
- Electrical connection screw terminals
- Input resistance < 50 kW (static)
Accessories (external)
Thermometer for RITTER Bellows-type Gas Meters
Measuring Range: 0 °C to + 60 °C
Scale graduation: 1 °C
Application
The Thermometer can be used for measurement of the gas temperature while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure. The norm volume of a gas is the volume at norm conditions which are (in Germany).

The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm Temperatur | = 273,15 Kelvin ( = 0 °C) |
Norm Druck | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
VN | = | Norm Volume in | [ltr] |
Vi | = | Indicated Volume in | [ltr] |
pN | = | Norm Pressure in | [mbar-absolut] |
pa | = | Actual Pressure in | [mbar-absolut] |
TN | = | Norm Temperatur in | [Kelvin] |
Ti | = | Indicated Temperatur in | [Kelvin] |
Installation
Unpack the Thermometer which is mounted into a T-piece. According to the rules for calibration and measurement with gas meters, the Thermometer must be positioned at the gas outlet of the meter. The gas outlet nozzle is labelled accordingly.
Mount the Thermometer onto the gas outlet nozzle by tightly screwing the union nut which is attached to the Thermometer. The Thermometer is now ready for use.
Manometer for pressure pmax = 60 mbar
Type | Capsule pressure gauge |
Measuring Range | 0 to 60 mbar |
Resolution | 2 mbar |
Material: Stainless steel (Cr-Ni)
Application
The Manometer for pressure pmax = 60 mbar can be used for measurement of the gas pressure while measuring the gas flow. Among other reasons, this is necessary if the measured and indicated actual volume of gas must be recalculated into the norm volume. The actual volume is the volume at the actual temperature and the actual pressure.

The norm volume of a gas is the volume at norm conditions which are (in Germany):
Norm Temperatur | = 273,15 Kelvin ( = 0 °C) |
Norm Druck | = 1.013,25 mbar |
The formula for converting the actual volume into norm volume is:
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Note: The indicated gas pressure at the manometer is the differential pressure between the gas pressure at the gas inlet and the actual atmospheric air pressure. Thus, the actual gas pressure (pa) to use in the above formula is the indicated gas pressure at the manometer plus the actual atmospheric air pressure in [mbar].
Installation
Unpack the Manometer which is mounted into a T-piece. According to the rules for calibration and measurement with gas meters, the Manometer must be positioned at the gas inlet of the meter. The gas inlet nozzle is labelled accordingly.
Mount the Manometer onto the gas inlet nozzle by tightly screwing the union nut which is attached to the Thermometer. Thus, the Manometer is ready for use.
Electronic Display Unit »EDU 32 FP«
General Overview
Application
The EDU 32 FP accessory is a microcomputer-controlled counter and display apparatus. It is designed to be used in conjunction with RITTER Gas Meters, to count and display the abso-lute volume and flow-rate of Gases flowing through the RITTER Meter. It consists of a unit in a separate (desk top) casing with a two-line Plain-Text-LCD-Display, and can be used with all types of RITTER Gas Meters. The following individual alterations and functions can be programmed via the Control Buttons:
- Gas Meter type being used
- Individual measurement range (min./max. flow rates) for custom-built Gas Meters
- Upper and lower limiting values for Flow Rate
- Pulse Generator in use: Standard (200 Pulses per revolution of the measurement drum), Ex-Proof (50 Pulses/Revolution) or custom-built Models (customer-preferred number of pulses under 200 or 50 respectively)
- Language German/English in the Display
- Analog-Output: Current Output or Voltage Output
- Contrast adjustment of the Display
Technical Data
Power supply
- either 110 V / 60 Hz or 230 V / 50 Hz (must be specified with order)
- Over-/undervoltage:
- +15%
- -5% (with Current Output “On”)
- -20% (with Current Output “Off”)
- 6 Volt Accumulator for battery operation
- Standart power socket, power cord (1)
Input
Pulses from Pulse Generator built into Gas Meter, round 5-pin-socket suitable for all RITTER Drum-type Gas Meters and Bellows-type Gas Meters (Type and Model programmable via the control buttons).
Output
- Interface RS 232 (Standard Sub-D-9-pin-socket):
- Signal: +/- 15 Volts
- Transmission rate: 9,600 Baud
- Data = 8 Bit, Parity = N, Stopbit = 1
- Analog Output, programmable, round 5-pin-socket:
- Current Output: 4 – 20 mA or 0 – 20 mA or
- Voltage Output : 0 – 1 Volt
Display
- large 2-line LCD Display, 16 characters per line
- Display language programmable: English / German
- Display contrast adjustable (via the Menu)
- Display of:
- measured Gas Volume in [Liters]
- actual Flow Rate in [Liters per hour]
- programmed Gas Meter type/model
- power status (Mains / Battery / Low Batt)
Control elements
- Push-buttons, waterproof
Button | Function |
ON/OFF | On/Off |
RESET | (in measurement Mode): Resetting the Display to zero |
ENTER | (in set-up mode): For scrolling through provided Menu Options and saving of selected option |
MODE | (in measurement Mode): Choice of Display “Volume” and/or “Flow Rate” |
SELECT | (in set-up mode): For selection of required Menu Option |
Further Functions
- Data transmission via RS 232 to a PC
- Configuration of the EDU 32 FP from the PC
- Pre-selection of a minimal or maximal Flow Rate
- Acoustic Signalling (Beep) when the Flow Rate values exceed the pre-selected min./max. range
- Power supply for the power interface can be turned off (to in-crease the running time during battery operation)
Control Codes
(for data transmission from Interface RS 232 to Computer)
- Ctrl-V (Hex 16) provides: VOL 00000,00 LTR
- Ctrl-F (Hex 06) provides: FLOW 000,00 L/H
- Ctrl-C (Hex 03) causes: RESET
- Ctrl-T (Hex 14) provides: Type + Power Status
Fuse
- 0.1 Ampere – located at the rear wall in a fuse drawer below the power socket. The fuse drawer contains a spare fuse as well.
Dimensions
- Width x depth x height = 155 x 200 x 120 mm
Weight
- 1,4 kg
Temperature Range
- 0 °C to + 50 °C
Scope of supply
- Power cord (with delivery into countries with German Standard for socket / plug only)
- Connection cord to Pulse Generator