CTF Clamp On Gas Flowmeter for Low Pressure Applications

CTF878 Clamp On Gas Meter

  • Only flowmeter worldwide to measure low pressure flows (<5 bar) Worldwide support/installation by experienced engineers
  • No Downtime - minimal installation costs Wide range of applications including natural gas, corrosive/toxic gases, low pressure
  • Correlation Tag Technology Unique technology providing accuracies of +/-1 to 2% of rate. AGA compliant
  • Sales, Rental & Installation
Product Options


The DigitalFlow CTF878 Correlation Tag Clamp-on Gas Ultrasonic Flowmeter is suitable for metal pipes and for pressure as low as atmospheric. It is non-invasive, has no wetted parts or moving parts. There is therefore no process down time or significant installation costs for this clamp on technology.

The CTF878 uses a new technology called correlation tag, to determine the flow rate of gases. This is like no other clamp on gas flowmeters. The CTF878 flow meter is supplied with two pairs of ultrasonic transducers - the first measure the upstream disturbance, and the second (situated downstream) record the downstream disturbance. The flow meter constantly samples these traces and correlates the two traces. When the flow meter recognises that the same disturbance pattern has travelled along the pipe, it is possible to measure the velocity. This is done constantly every second. Each pair of transducers includes a transmitter sending ultrasound in a continuous wave mode through the fluid to the receiver, forming an upstream and downstream interrogation path. The continuous wave signal is modulated by turbulence and local density variations that are characteristic of a moving gas.

In the past, a restricting factor in gas measurement has been the signal strength of transducers: having to send an ultrasonic signal through the metal pipe wall, through the gas, and then back through the pipe wall again. New clamp-on gas transducers produce signals that are five to ten times more powerful than signals of traditional ultrasonic transducers. This new technology produces clean, strong signals with marginal background noise.

Specifications assume a fully developed flow profile (typically 20 diameters upstream and 10 diameters downstream of straight pipe run).

Manufactured by: GE Panametrics
Model: CTF878 Clamp On Gas Meter

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Natural gas
Compressed air
Low Pressure Applications
Fuel gases
Corrosive gases
Toxic gases
High-purity gases
Air separation gases
Speciality gases


Fluid Types All acoustically conductive gases. Minimum gas density:
0.074 lb/ft3 (1.2 kg/m3). Gas should not be wet or saturated with moisture.
Pipe Sizes 6 in to 30 in NB ANSI (152 mm to 762 mm DN)
Pipe Wall Thickness Up to Sch 80
Pipe Materials Most metals and plastics. No lined pipes.
Flow Accuracy (Velocity) ±2% of reading at 3.5 to 150 ft/s
(1.1 to 46 m/s) typical
Repeatability ±0.2% to 0.6% at 3.5 to 150 ft/s
(1.1 to 46 m/s)
Range (Bidirectional) ±150 to ±3.5 ft/s (±46 to ±1.1 m/s)
Rangeability (Overall) 43:1
Measurement Parameters Velocity, actual and standard volumetric flow, and totalized flow
Flow Measurement Correlation tag technique
Dimensions (standard) (h x w x d) 14.24 in x 11.4 in x 5.12 in
(362 mm x 290 mm x 130 mm)
Weight (standard) 11 lb (5 kg)
Channel Single channel
Display 240 x 200 pixel backlit LCD graphic display
Keypad 24 key rubberized tactile membrane
Power Supply
85 to 264 VAC, 50/60 Hz
Operating Temperature -14°F to 131°F (-10°C to 55°C)
Standard Inputs/Outputs Two 0/4 to 20 mA isolated outputs, 550 S maximum load


Related products


Yes, the ordering process is very easy. Orders can be made via purchase order or by credit/debit card. Once we have the paperwork we can delivery next day to any location in Europe. Provided with the equipment is a quick start guide, and if you need extra support, the technical support engineers can be contacted via phone call.
No, all of our flowmeters are competitively priced and rental is an ideal option for cutting costs to a fraction of a full priced new flowmeter.
No problem. The quick start guide is designed to make installing the flow meters a simple task. Everything you require for set up will be found in the peli-box supplied with the flowmeter.
Every flow meter is tested upon shipping and return as part of our ISO9001 procedure. Also, as part of this procedure, the flow meter is calibrated once a year. If a copy of the calibration certificate is needed let us know.
The flow meters typically provide an accuracy of ±1 to 2% of rate, so if you are measuring 100l/sec then the accuracy is between 98-102l/sec.
We are here to help. If the self-help and quick start guides do not help, then call one of our technical support engineers on +44 (0) 1527 882060. We have supplied and supported many clamp on rental installations throughout Europe.
First, contact us for a quote. If you are happy with the quote then send us a purchase order. Or alternatively call us with credit card details and fill out and send us a rental agreement form.
If the stock is permitting, and all paperwork is received by 12pm then flow meters can usually be available the next day.
The minimum hire period for flow meters is one week.
Once you have the meter you can rent it for as long as you need it. However, it would help if you can let us know that you wish to extend the rental period. Upon return the meter is off-hired and once checked and tested, an invoice will be issued to you. Also, if you extend your rental past a 4, 8 or 12 week rental threshold, then you are entitled to a discount.
You are only charged for the period of time for which you have the flowmeter. So, if a flowmeter is returned 3 days late you are only charged for 3 extra days, and each of these days is charged at one fifth of the weeks hire cost.
Normally, you will use your own courier but if you have any problems let us know and we can arrange a pick up the day after you notify us, but you will be charged for the carriage and this cost will be added to the invoice.
Without exception, all our flow meters are tested. If you need a 110v plug instead of the standard 230v plug let us know.
All of our standard transducers will do -40degC to +150degC, but this will depend on your application.
  • Liquid: below 50mm CFLP transducers are required, 50-1000mm CRS-402 transducers and 150-8000mm CRS-401 transducers. All the bits you need can be supplied, and delivered with the meter.
  • Gas: below 80mm CRS-402 is required, for 80-300mm the CRS-401/CRV-310 and for above 300mm the CRW-312 transducers are required.
  • High temperatures: For liquid we can measure +450degC for liquid and for gas/steam +250degC. But please consult RS Hydro.
Of course, we make a small surcharge for each set of transducers. Most applications only require one set, but on occasion some people may require two, for more diverse pipe sizes and applications.
As long as the pipe is relatively clean, coatings or paint is usually not a problem for clamp on flow meters but if the pipe is corroded or the paintwork has bubbled then a quick sanding down with sandpaper or a wire brush is recommended.
An ultrasonic wall thickness gauge, that measures to within 0.05mm, is provided as standard with all flow meter rental packages.
The screendump facility on the integrated dataloggers on all our flow meters, allows you to photograph any screen and download it to your pc.
After the equipment has been shipped, it is the responsibility of the hirer. However, in our experience it is rare that any of our flow meters are damaged. Our flow meters are tough, as well as accurate, and reliable.
We have hired more ultrasonic clamp on flow meters than any other company in Europe. We are now one of the world's largest distributors of GE Panametrics flow meters. We always review your application before hire so no unwanted surprises are encountered. Every effort has been made to make your flow meter hire and enjoyable experience: quick start guides to help you set up with ease, online videos for further help, rugged packaging for extra durability anywhere, and real flow engineers available for online/telephone support.