Why is it necessary to set up a pressure regulator in the town gas transmission and distribution system?

In order to regulate and control the pressure of the gas in the gas transmission and distribution network in towns and cities, it is necessary to set up a gas pressure regulator. Its role is to reduce the high pressure gas to the required pressure, and keep its outlet pressure unchanged. Pressure regulating device in the regulator is its main equipment.

In the town gas transmission and distribution pipeline network system, gas regulator set up in the town gas source, gate station, storage and distribution station, pressurization station, gas distribution station, filling station, between all levels of pressure pipeline network, distribution pipeline network and the user.

How many types of gas regulators are there? What is the difference?

Pressure regulators can be divided into two types: direct-acting and indirect-acting. Indirect-acting regulators rely on changes in outlet pressure felt by the sensitive element (membrane) to regulate the degree of valve opening. Indirect action regulator outlet pressure changes, so that the manipulation mechanism (such as commanders) action, connecting energy (can be external energy, can also be divided into regulated media) to change the opening degree of the regulator valve.

Regulators can also be divided by purpose or object of use for the field, station regulator regulator, regulator for the network regulator regulator, regulator for special pressure regulator and regulator for the user; according to the structure can be divided into float and film regulator import and export pressure is divided into high-pressure, high medium-pressure, high and low-pressure, medium-pressure, medium-low pressure, low-pressure and low-pressure regulator.

According to the location in the town gas transmission and distribution system and the role of how to categorize the gas regulator?

According to the town gas transmission and distribution system location and role, gas regulator can be divided into:

( l ) station and field regulator

Station, field pressure regulator refers to the gas source, gate station, storage and distribution station, gas distribution station, gasification station, gas mixing station, filling station and other regulator system. It is designed and constructed according to the process needs of the station or field. Generally, the import and export pressure of the regulator is higher, and according to the conditions and requirements can be set up in the open air or indoor; the regulator is generally equipped with metering equipment to measure the gas in and out of the station.

( 2 ) Network pressure regulator

Network pressure regulator refers to the pipeline network at all levels in the transmission and distribution system to change the pressure set by the regulator system. The import and export pressure is determined by the pressure level system of the transmission and distribution system. Network pressure regulator is generally located in a dedicated building. In the network pressure regulator generally do not need to set up measuring equipment, network pressure regulator can be divided into network connection regulator and regional pressure regulator.

(l) network connection regulator

Network connection regulator: gas transmission and distribution system in the pipe network pressure level system is three or more, regulator outlet pressure for medium pressure or more, its network is not directly connected to a large number of users of the network regulator.

(2) Regional pressure regulator

In the transmission and distribution system, the outlet pressure of the pressure regulator is low pressure, and the pipeline network is directly connected to a large number of users of the network pressure regulator. Regional pressure regulator in a certain area within the scope of the gas supply to the user.

( 3 ) Specialized pressure regulator

Specialized pressure regulator is a town gas transmission and distribution system directly to industrial users or large commercial users separate gas supply regulator system. Specialized pressure regulator should be designed for the amount of equipment. According to the size of the import pressure and environmental conditions can be located in the open air, separate, single-story buildings, gas buildings adjacent to single-story buildings, separate, single-story buildings in the production workshop, gas buildings on the top floor and the roof platform. Specialized regulator can also be located in the regulator cabinet or regulator box according to the size.

( 4 ) User pressure regulator

User pressure regulator is used to supply one household or one (or several) residential residential users to use the pressure regulator system. Supply a household regulator is generally set up in the gas appliances, the pressure of its inlet pipe section is relatively high, and laid indoors, so the necessary safety measures should be taken to ensure safe operation. The pressure regulator for supplying one (or several) residential users is generally installed in the courtyard or in a metal box hanging on the outside wall of the building.

How to classify the gas regulator according to the form of regulator enclosure?

According to the form of regulator enclosure structure is divided into:

( l ) open-air regulator

When the natural conditions and the surrounding environment permits, the station regulator and the special regulator located on the roof platform of the gas-using building can be used for open-air laying, known as open-air regulator. A guardrail or fence shall be set up around them.

( 2 ) regulator station

The network regulator and special regulator located in a separate building are called network regulator and special regulator.

( 3 ) regulator cabinet

Set in the prefabricated cabinet enclosure regulator is called regulator cabinet. General network regulator station and special regulator station can be used in the form of regulator cabinet.

( 4 ) regulator box

Set in the metal box regulator said regulator box. User regulator to supply a (or several) residential users of the regulator can be used regulator box. Specialized regulators can also be used regulator box type.

How to categorize pressure regulators according to the pressure adjustment range?

According to the pressure adjustment range of the regulator is divided into:

( l ) high a high regulator

Gas inlet pressure and rated outlet pressure are high pressure regulator. Generally in the station, the field regulator and the network connection regulator station can be high a high regulator station.

( 2 ) High and medium regulator station

Gas inlet pressure is high pressure, rated outlet pressure is medium pressure regulator. It is used for station regulator and network connection regulator.

( 3 ) High and low regulator station

The gas inlet pressure is high pressure, the rated outlet pressure is low pressure regulator station, used for regional regulator station.

( 4 ) Medium and medium regulating stations

A regulating station where the gas inlet pressure and rated outlet pressure are both medium pressure, used for network connection regulating stations.

( 5 ) Medium-low regulating station

The gas inlet pressure is medium pressure and the rated outlet pressure is low pressure regulating station, which is used for regional regulating station.

( 6 ) Low one low regulating station

This is a regulating station where the gas inlet pressure and rated outlet pressure are both low pressure, and is used for regional regulating stations and customer regulating devices.

How to categorize the regulator according to the building form?

According to the building form of the regulator is divided into:

( l ) above ground regulator

In order to ensure the safe operation of the regulator and facilitate the operation and management, the regulator is generally located on the ground.

( 2) underground regulator

When the construction of regulator on the ground is restricted, and the inlet pressure is less than O. 4MPa, it can be considered to use the underground regulator. 4MPa, underground regulator can be considered. However, due to the inconvenience of maintenance and operation of underground pressure regulator and easy to occur safety accidents, therefore, only in the construction of the ground pressure regulator is very difficult to use.

What are the ancillary equipment of gas regulator?

In addition to the main equipment regulator, the gas pressure regulator also includes the following auxiliary equipment: valves, filters, safety devices, bypass pipes, measuring instruments.

What are the safety facilities of the regulator?

The safety facilities of the pressure regulator are as follows:

Safety valves, safety shut-off valves, parallel monitor devices, series monitor devices, combined safety devices.

Safety valve, safety shut-off valve, parallel monitor device, combined safety device.

How is the safety valve activation discharge pressure of a gas regulator determined?

The safety valve of the gas regulator is located at the outlet of the regulator, and when the outlet pressure exceeds the specified value, a certain amount of gas will be discharged into the atmosphere, so that the outlet pressure will be restored to the permissible range and uninterrupted gas supply will be maintained. Discharge pressure is set according to the following table.

Safety valve start pressure value start dissipation pressure Ps

Regulator outlet

Starting Discharge Pressure Ps

Low pressure

Ensure that the directly connected appliances are within the safe working pressure

P2≦0.08

Less than 50 % of the upper limit of regulator outlet pressure, i.e. Ps≦1.5P2max

0.08≦P2≦0.4

Less than the upper limit of regulator outlet pressure 0.04, i.e. Ps≦1.5 P2max﹢0.04

P2﹥0.4

Less than 10 % of the upper limit of regulator outlet pressure, i.e. Ps≦1.1 P2max

What is the difference between the process flow of various gas regulators?

The process flow of various types of regulators is basically the same. But for special regulator should be added in the process of metering device.

What requirements should be met in the process design of town gas regulator?

The process design of the regulator shall comply with the following requirements:

(1) The regional regulator station of the low-voltage pipeline network without loop and the user regulator used for continuous production shall be equipped with standby regulator, but in other cases, the regulator may not be used for equipment.

The gas import and export pipelines of the regulator should be equipped with bypass pipes, and the user regulator box (hanging type) may not be equipped with bypass pipes. ( 2) high-pressure and low-pressure gas regulator station outdoor inlet and outlet piping must be set on the valve; medium-pressure gas regulator station outdoor inlet piping should be set on the valve.

( 3) The distance of valves on the outdoor inlet and outlet pipelines of the regulating station from the regulating station:

(l) when the ground for independent buildings, should not be less than 10m (when adjacent to the building, should not be less than 5m).

(2) When the regulator cabinet, should not be less than 5m.

(3) When the open-air regulator station, should not be less than 10m.

(4) when the branch pipe valve to the regulator station is less than 100m from the regulator station, outdoor branch pipe valve and regulator station inlet valve can be combined into one.

( 4) In the regulator gas population should be installed filter.

( 5) in the regulator gas population (or outlet), should be set to prevent gas outlet pressure is too high safety protection devices (when the pressure itself with safety protection devices may not be set).

( 6) regulator safety protection device should be selected manual reset type. Safety protection (discharge or cut-off) device must be set to start the pressure value and have sufficient capacity. Starting pressure should be determined according to process requirements.

( 7) Discharge pipe opening should be above 1.0m above the eaves of the regulator station.

The height of the safety discharge pipe of the regulator cabinet from the ground should not be less than 4m: the safety discharge pipe of the regulator set on the wall of the building should be 1.0m above the eaves of the building.

Underground regulator station and underground regulator box should also be set in accordance with the provisions of the ground regulator cabinet safety discharge pipe opening.

Note: When the discharge pipe for cleaning pipe blowing, the discharge pipe of the conductor and the safety water seal discharge pipe belong to the same working pressure, it is allowed to connect them to the same discharge pipe.

( 8 ) Pressure regulator and filter before and after the regulator station should be set to indicate the type of pressure gauge. After the regulator should be set up after the automatic recording type pressure meter.

What requirements should be met when considering the installation of a town gas pressure regulator?

The following requirements shall be met when considering the installation of town gas pressure regulating devices:

( 1 ) natural conditions and the surrounding environment permits, it is appropriate to set up in the open air, but should be set up fences, guardrails or car stops; ( 2 ) set up on the ground within a separate regulator cabinet (hanging type), for residential and commercial users of the gas inlet pressure should not be greater than 0.4MPa; for industrial users (including boilers) gas inlet pressure should not be greater than 0.8MPa;.

( 3 ) set on the ground in a separate regulator cabinet (floor-standing), the residential, commercial and industrial users (including boilers) gas import pressure should not be greater than 1.6MPa.

( 4 ) when conditions permit can be set on the ground in a separate building;

( 5 ) when restricted by the conditions above ground, and pressure regulator import pressure is not greater than 0.4MPa, can be set up in a separate underground building or underground separate box.

Liquefied petroleum gas and relative density of 0.75 gas regulator shall not be set in the basement, semi-basement and underground separate box.

Gas regulator (regulator cabinet) should be set up to meet what requirements?

Regulator (and regulator cabinet) should be set up in accordance with the following requirements:

( l ) regulator box (hanging type)

(l) regulator box bottom height from the floor should be 1.0-1.2m, can be installed in the gas building on the outside wall or hanging in a special bracket; when installed in the gas building on the outside wall, regulator import and export pipe diameter should not be greater than DN50.

(2) regulator to the building doors, windows or other holes leading to the interior of the horizontal clearance should be consistent with the following provisions:

When the regulator inlet gas pressure is not greater than 0.4MPa, should not be less than 1.5m.

When the regulator inlet gas pressure is not greater than 0.4MPa, should not be less than 3.0;.

Regulator should not be installed in the building doors, windows on the upper and lower walls and balconies below; should not be installed in the indoor ventilator inlet wall.

(3) Installation of the regulator box wall should be a permanent solid wall, the fire-resistant grade of the building should not be less than two.

(4) The regulator box should have natural ventilation holes.

( 2 ) regulator cabinet (floor type)

(l) the regulator cabinet should be set up on a solid foundation, the height of the cabinet bottom from the floor should be 0.30m.

(2) Horizontal clearance from other buildings and structures should be consistent with the provisions of Table 4.1.60 in this chapter.

(3) volume greater than 1.5m3 of the regulator cabinet should be explosion relief port, explosion relief port should not be less than the upper cover or the largest cabinet wall area of 50 % (whichever is greater). Explosion vent should be located on the cover. Vent area can be included in the calculation of the explosion relief port area.

(4) regulator cabinet should be natural vents, the setup should meet the following requirements:

( 1 ) when the relative density of gas is greater than 0.75, should be in the cabinet, under the cabinet, each set 1% of the bottom area of the cabinet vents, regulator cabinet should be surrounded by guardrails;

( 2 ) when the relative density of gas is not greater than 0.75, can only be set in the upper part of the cabinet 4% of the cabinet bottom area vents; regulator cabinet should be set around the guardrail.

( 3 ) installation regulator box ( or cabinet ) location should be able to meet the regulator safety device installation requirements.

( 4 ) installation regulator box ( or cabinet ) location should make the regulator box ( or cabinet ) is not collision, does not affect the view and in the open box ( or cabinet ) operation does not affect the traffic.

What requirements should be met when setting up an underground regulator box?

Underground regulator setup should meet the following requirements:

( l ) underground regulator box should not be set in the town under the road, from other buildings, structures, horizontal clearance should be consistent with the chapter Table 4 . 1 . 60 of the provisions;

( 2 ) underground regulator box should be natural vents, the setup should be in line with the relevant provisions of the gas regulator (regulator cabinet);

( 3 ) The location of the underground regulator box should be able to meet the installation requirements of the regulator safety devices;

( 4 ) The underground regulator box should be set up to facilitate maintenance;

( 5 ) underground regulator should be corrosion protection.

User-specific regulator settings should meet what requirements?

Setting up user-specific regulator, in addition to the general requirements, should also meet the following requirements:

( l ) When the commercial user regulator import pressure is not greater than 0.4MPa, or industrial users (including boilers) regulator import pressure is not greater than 0.8MPa, can be set up in a single-story adjoining building dedicated to gas buildings:

(l) The building should be separated from neighboring buildings by firewalls without doors, windows and openings, and the horizontal clearance with other buildings and structures should be in accordance with the provisions of Table 4.1.60 of this chapter;

(2) The fire resistance level of the building should be in line with the current national standard "building design fire code" GBJ16 not less than "two" design provisions, and should have a light structure of the roof of the explosion relief ports and windows and doors open to the outside;

(3) The ground should be used for materials that do not produce sparks;

(4) indoor ventilation should not be less than 2 times per hour;

(5) indoor electrical, lighting should be in line with the current national standards, "explosion and fire hazardous environment power plant design code" GB 50058 "1 zone" design provisions.

( 2 ) When the pressure regulator import pressure is not greater than 0.2MPa, can be set up in public buildings on the top floor of the room: l ) The room should be by the building facade, should not be arranged in a crowded room on top of or close to the neighboring, and meet the requirements of the second level of fire-resistant buildings, non-ignition of flowers on the ground, the electrical lighting for the work area and other requirements;

(2) The room should be equipped with a continuous ventilation device, and can ensure that the number of ventilation more than 3 times per hour;

(3) The room should be set up to monitor the combustible gas concentration detection instrumentation and sound and light alarm devices. The device should be interlocked with ventilation facilities and emergency shut-off valve, and the signal should be led to the monitoring room of the building;

(4) The pressure regulator should be equipped with automatic cut-off protection device for overpressure;

(5) The outdoor inlet pipeline should be equipped with valves and can be operated on the ground;

(6) pressure regulator and gas piping should be welded and flanged steel pipe connection.

( 3 ) When the pressure regulator import pressure is not greater than 0.4MPa, and regulator import and export pipe diameter is not greater than DN100, can be set in the flat roof of the gas building, but should meet the following conditions:

(1) should be in the roof of the load-bearing structure under the conditions of force allowed, and the building fire-resistant grade should not be less than two;

(2) The building should have access to the roof stairs;

(3) The horizontal clearance between the regulator box, cabinet (or open regulator) and the chimney of the building should not be less than 5m.

(4） When the inlet pressure of the pressure regulator is more than 0.4MPa, it can be set in the production workshop, boiler room and other industrial production gas rooms of single-story buildings, or when the inlet pressure of the pressure regulator is not more than 0.8MPa, it can be set in the production workshop or boiler room of a separate, single-story building, but it should meet the following conditions:

1) The above requirements shall be met;

2) The diameter of the inlet and outlet pipes of the pressure regulator should not be larger than DN80.

3) regulator should be equipped with non-combustible body guard;

4） In addition to the inlet valve of the regulator indoors, a valve should also be set on the outdoor lead pipe.

Note: When the regulator import and export pipe diameter greater than DN80, should be set in the gas regulator building dedicated single-story room.