GB/T 37499-2019Safety and control devices for gas burners and gas-burning appliances - Particular requirements - Automatic and semi-automatic valves (English PDF)

3.1 Automatic shut-off valve

A valve that opens when power is supplied and automatically closes when power is depleted, and has a safety shut-off function.

3.2 Semi-automatic shut-off valve

A valve that can be manually opened and automatically closed when power is depleted, and also has a safety shut-off function.

3.3 Thermoelectric valve

An automatic shut-off valve that is directly driven by thermoelectric potential energy.

3.4 Valve with step control

A valve that controls flow in steps.

3.5 Valve with modulating control

A valve that continuously controls the flow rate between two flow rate setpoints based on an external signal.

3.6 Actuating mechanism

The component in a valve that moves the closing element.

3.7 Actuating pressure

The pressure that drives the valve actuator to perform its actions.

3.8 Control valve

A valve that controls the pneumatic or hydraulic supply to the actuating mechanism.

3.9 Actuator

to flow.

3.19 C/I valve

Automatic or semi-automatic shut-off valves with special performance requirements in terms of materials, airtightness, and durability.

4.1 Classification

In addition to complying with the provisions of 4.1 in GB/T 30597-2014, valve classification shall also meet the following requirements.

a) Classification by sealing force.

--- Class A, B, and C valves. Valves whose sealing forces do not decrease with changes in gas inlet pressure and can be safely closed; they are classified into Class A, B, and C according to the sealing force requirements specified in 6.3.5.7 a).

--- Class D valves. Valves without sealing force requirements.

--- Class J valves. Valves whose sealing forces do not decrease with changes in gas inlet pressure, can be safely closed; and meet the requirements of 6.3.5.7 b).

b) Classification by function.

--- C/I valves;

--- Automatic shut-off valves;

--- Semi-automatic shut-off valves;

--- Valves with modulating control;

--- Valves with step control.

4.2 Grouping

Valve grouping shall comply with the provisions of 4.2 in GB/T 30597-2014.

5.1 General requirements

The general structure of the valve shall conform to the provisions of 5.1 in GB/T 30597-2014.

5.2 Structure

5.2.1 Appearance

The appearance of the valve shall conform to the provisions of 5.2.1 in GB/T 30597-2014.

5.2.2 Orifice

The orifice of the valve shall conform to the provisions of 5.2.2 in GB/T 30597-2014.

5.2.3 Breathing hole

The valve's breathing hole shall conform to the provisions of 5.2.3 in GB/T 30597-2014.

5.2.4 Fastening screws

The valve's fastening screws shall conform to the provisions of 5.2.4 in GB/T 30597-2014.

5.2.5 Moving parts

The valve's moving parts shall conform to the provisions of 5.2.5 in GB/T 30597-2014; and the screws or nuts of any operable moving part shall not fall off under normal operating conditions.

5.2.6 Protective cover

The valve's protective cover shall conform to the provisions of 5.2.6 in GB/T 30597-2014.

5.2.7 Disassembly and reinstallation for maintenance and/or adjustment

In addition to complying with the provisions of 5.2.7 in GB/T 30597-2014, the disassembly and reinstallation of valves for maintenance and/or adjustment shall also comply with the following provisions.

a) When only exit-factory adjustment is required and on-site adjustment is not required, measures shall be taken to prevent mis-operation to protect, or appropriate protective measures shall be provided in the instruction manual.

NOTE. Examples of protective measures are as follows.

--- A seal with a temperature range consistent with the valve's operating temperature range and clearly marked;

--- Designed to be operable only with special tools;

--- The instruction manual clearly states that the manufacturer provides protective measures to prevent mis-operation during valve installation.

b) When the adjustment method requires maintenance, such adjustment components shall have measures to prevent mis-operation (e.g., using a spring-loaded locking nut or adjusting nut).

c) When on-site commissioning is necessary, the valve shall be equipped with a protective cover conforming to the provisions of 5.2.6, or protected against tampering and mis-operation.

5.2.8 Auxiliary channels

The auxiliary channels for valves shall conform to the provisions of 5.2.8 in GB/T 30597-2014.

5.2.9 Closed position indicator switch

The closed position indicator switch of the valve shall comply with the following provisions.

a) The installation position of the switch shall not affect the normal operation of the valve;

b) The regulator of the switch shall prevent misadjustment;

c) When the settings of the switch and the regulating mechanism deviate, it shall not affect the normal operation of the valve;

d) When the switch is used as a proof-of-closure switch, the switch contacts shall close after the valve port is closed and open before the valve port is opened. The additional travel of the switch after the valve port is closed can be provided by the valve port closing element or by an additional actuator. When an additional actuating mechanism is used, the additional actuating mechanism shall be designed to function only when the closing element is in the closed position;

e) The switch shall be set when it leaves factory and shall be sealed to prevent misadjustment.

5.2.10 Flow regulating and setting

The structural design of the valve shall ensure that its flow regulating and setting comply with the following provisions.

a) The adjustment range of the valve with modulating control shall be consistent with the manufacturer's instructions;

b) When different flow settings affect each other, this shall be stated in the installation instructions;

c) The flow setting shall only be performed by tools, and the flow regulating element shall be closed.

5.2.11 Valve mechanism protection

The valve shall be protected by a robust housing to prevent interference with its normal operation.

5.2.12 Bypass

Bypasses are not permitted for Class A, B, C, D, J, and C/I valves.

5.2.13 C/I valves

5.2.13.1 Closing force

C/I valves shall not be designed to use gas pressure, flow rate, or external energy as the closing force.

5.2.13.2 Position indicator

When a C/I valve includes a position indicator, the position indicator shall be connected to the valve closing element.

NOTE. The position indicator indicates the valve's closed position.

5.2.13.3 Semi-automatic C/I valves

Manually operated semi-automatic C/I valves shall only be allowed to be fully open.

5.3 Materials

5.3.1 General requirements

Valve materials shall comply with the provisions of 5.3.1 in GB/T 30597-2014.

5.3.2 Housing

In addition to complying with the provisions of 5.3.2 in GB/T 30597-2014, the valve housing shall also comply with the following provisions.

a) When the diaphragm is used as a component to isolate the atmosphere and fuel gas within the housing (i.e., indirect isolation), the valve housing shall be made of metallic material;

b) The valve body and its internal components (except for valve plugs, gaskets, O-rings, etc.)

of the C/I valve shall be made of materials with a melting point no lower than 427 degrees C.

5.3.3 Springs

5.3.3.1 Closing springs

The closing springs of valves shall comply with the provisions of 5.3.3.1 in GB/T 30597-2014.

5.3.3.2 Springs providing closing force and sealing force