These technical conditions (hereinafter - TU) apply to items (units, units) for measuring the flow and volume of gas "PVVG" (hereinafter - items) which are designed to measure consumption ( volume ) and commercial and technological accounting natural gas (according to GOST 5542), as well as air, nitrogen and other non-aggressive gases with an operating pressure of up to 10.0 MPa.
The points are intended for use in gas distribution and gas supply systems of settlements, industrial and agricultural facilities, public and communal buildings, residential buildings, etc., as well as in air, nitrogen and other non-aggressive gas metering systems at industrial facilities.
The items may include meters and volumes of gas (meters, flow meters, sensors, measuring systems, etc.), depending on the technical task.
Depending on the purpose, execution and the applied equipment points can be made in the following executions :
- on a frame (frame) - PVVG-R:
- in a metal case (cabinet) - PVVG-Sh;
- in a block box or in a container (block) - PVVG-B.
Execution P - installation of the equipment which is included in point, is carried out on a metal frame. For placement in heated rooms - without protection of separate knots; for outdoor use - with the use of insulated cabinets for gas meters and pressure and temperature transducers.
Execution Ш - installation of the equipment which is included in point, is carried out in a protective metal case (not warmed and not heated, warmed and not heated, warmed and heated (with gas heating or electric heating )).
Execution B - installation of the equipment which is included in point, is carried out in a block box (container).
Items depending on the measurement method used, are performed in the following modifications:
- with an ultrasonic gas meter (hereinafter - ULG);
- with turbine meter;
- with a rotary counter;
- with measuring diaphragm;
- with narrowing devices;
- with other measuring instruments.
The choice of the type of gas flow measurement means depends on the range of gas flow measurement, purpose and operational characteristics of the point, requirements of the design documentation. The type and brand of the gas meter is agreed with the customer.
The designation of items when ordering and in the design documentation should consist of: product name, design, conditional passage of meters and measuring pipelines, maximum design gas pressure, number of gas metering lines, instructions on the presence of bypass line and line of "small" gas consumption, designation of these technical conditions.
1 2 3 4 5 6 7
1 - point for measuring the flow and volume of gas;
2 - execution of PVVG on installation of the equipment:
P - on a metal frame;
W - in a protective metal cabinet;
B - in the block box (container);
3 - conditional passage DN of metering devices and measuring pipelines;
4 - maximum design gas pressure at the inlet, MPa;
5 - the number of gas metering lines.
6 - the presence of a bypass line. If it is present, the letter "B" is present in the symbol;
7 - the presence of a line of "small" gas consumption. If it is present, the letter "M" is present in the symbol.
Example of recording the symbol when ordering and in other documentation:
1) Point for measuring the flow and volume of gas on the frame with a conditional passage of 200 mm and a maximum operating pressure of 6.3 MPa, with two gas metering lines, with a bypass and a line of "small" gas consumption:
" Point for measuring the flow and volume of gas PVVG-R-200-6,3-2-BM
TU U 42.2-04601469-067: 2020 ";
2) Point for measuring the flow and volume of gas in a protective metal cabinet with a conditional passage of 100 mm and a maximum operating pressure of 1.2 MPa, with one gas metering line and bypass :
" Point for measuring the flow and volume of gas PVVG-Sh-100-1,2-1-B
TU U 42.2-04601469-067: 2020 ".
According to the technical task, in addition to the measurement lines, the points can be additionally equipped with a block (blocks) of gas cleaning (preparation) and a unit (reduction line).
The points are intended for operation in areas with temperate and cold climates in the conditions normalized for performance of UHL, categories of placement 1 in accordance with GOST 15150 for work at ambient temperature from minus 30 ° C to 60 ° C and relative humidity of 98% at a temperature of 35 ° C .
Items with heating , designed to operate at ambient temperatures from minus 40 ° C to 60 ° C.
Items on the frame ( without protection of individual components) are designed for operation at temperatures from 5 ° C to 50 ° C, placement category 4.2.
The operating conditions of items other than those listed may be further specified in the individual order (depending on the operating conditions of the components used in a particular version of the item).
All types of items are manufactured using internal electrical equipment in fire or explosion-proof design.
To order the item, a questionnaire with passport characteristics must be drawn up.