ru en

The concept

The concept of the single-line gas measuring station (GMS) is meant to avoid the traditional multi-line GMS architecture and to switch to Vympel-500 large-diameter (DN 700 mm — 1400 mm) ultrasonic measuring system integrated directly into the main pipeline.
Both main pipeline and measuring system are located underground in a special caisson suitable for maintenance.
The measuring station uses a multi-path measuring channel layout with piezoelectric insertion angular input meters. This layout considers irregularity of speeds in the target medium stream diagram.
At the operation site, a bypass pipeline with existing valving designed for bypassing the compressor station with possible attachment of the reference standard is used as a testing rig.

Principles of operation

By operating principle the measuring station is classified as pulse-time flow meter working based on measuring the difference between ultrasonic probing pulses in the direction of the working environment flow in the primary transducer and against it.
Alternating switching of the "receiving-transmitting" modes of the sensor pairs is provided via the electronic unit. Gas flow displaces the ultrasonic wave, causing changes in the ultrasonic signal spread time between the sensors. Signal speed increases along the flow and decreases against.
The ultrasonic measuring system has 16 metering channels: 8 for the main measuring unit and 8 for the alternate unit, allowing for continuous control of the main unit's metrological parameters.

Main advantages

The main advantage of single-line GMS is several times cost reduction on capital construction of the GMS facility and its maintenance. It is achieved because of using of main pipeline fittings and compressor plant bypass pipeline.
High flow measuring stability — 0.1% — is ensured via a number of technical solutions:
  • 4 times as many measuring channels as there are in standard ultrasonic flow meters (16 against 4, respectively);
  • The environmental temperature is the same in summer and in winter, thanks to subterranean location of the measuring system;
  • Length of a straight section of the existing main pipeline before the measuring unit exceeds 100 DN (DN is the pipeline diameter).
The single-line GMS is an A-class measuring unit in accordance with the Gazprom Corporate Standard 5.37-2011.