Natural gas flame arresters are designed and manufactured based on the principle that flames extinguish due to heat loss when passing through narrow pores in thermal conductors. Suitable for storage and flare systems, gas purification systems, gas analysis systems, coal mine gas emission systems, heating furnace fuel gas pipelines for combustible gas pipelines, such as gasoline, kerosene, light diesel, benzene, methyl benzene, crude oil and other oil products, as well as pipeline supplies for acetylene, oxygen, nitrogen, and natural gas. This valve can be used in conjunction with a breathing valve or as a standalone device.
Item NO.:
XUVAL-385Lead Time:
45Product Orgin:
CHINABrand:
XUVALShipping Port:
Shang haiPayment:
100%Color:
RedMOQ:
1
DN |
Size |
L/mm | H/mm |
20 | 3/4" | 125 | 182 |
25 | 1" | 130 | 195 |
32 | 1-1/4" | 150 | 208 |
40 | 1-1/2" | 170 | 220 |
50 | 2" | 190 | 240 |
65 | 2-1/2" | 205 | 250 |
80 | 3" | 220 | 260 |
100 | 4" | 240 | 275 |
125 | 5" | 280 | 300 |
150 | 6" | 330 | 325 |
200 | 8" | 385 | 365 |
250 | 10" | 450 | 405 |
300 | 12" | 520 | 440 |
350 | 14" | 595 | 465 |
400 | 16" | 665 | 495 |
450 | 18" | 710 | 525 |
500 | 20" | 780 | 565 |
Technical parameters of natural gas flame arresters:
Model | ZHQ-Q | Explosion group | BS 5501: IIA IIВ IIС |
Size |
DN 15-600 GB 81~59
PN 0.6-2.5 FF、 RF
|
Bolt/Nut | 20# 304 304L 316 316L |
Body | A3 304 304L 316 316L | Diaphragm(P/V) | NBR PTFE Metal Gasket |
Flame Arrestor | 304 304L 316 316L | Ambient Temperature |
CS:-30°C ~ +350 °C
SS: -80°C ~ +480°C
|
Manufacture inspection | GB5908-86 GB/T13347-1992 | Jonit type | Flange Threaded |
Coating | CS:Paint SS:No paint | Flanges | HG GB SH HGJ JB ANSI JIS |
There are currently two main views on the working principle of natural gas flame arresters: one is based on heat transfer; One is based on the wall effect.
1. One of the necessary conditions for heat transfer and combustion is to reach a certain temperature, which is the ignition point. Below the ignition point, the combustion will stop. According to this principle, as long as the temperature of the burning substance is lowered below its ignition point, it can prevent the spread of flames. When the flame passes through many small channels of the flame arrester, it will become several small flames. When designing the internal flame arrester components, efforts should be made to expand the contact area between the small flame and the channel wall as much as possible, enhance heat transfer, and lower the flame temperature below the ignition point, thereby preventing flame propagation.
2. The wall effect combustion and explosion are not direct reactions between molecules, but are stimulated by external energy, causing the breakdown of molecular bonds and the generation of activated molecules. The activated molecules then split into short lived but very active free radicals, which collide with other molecules to produce new products and generate new free radicals that continue to react with other molecules. When the combustible gas passes through the narrow channel of the flame retardant element, the probability of collision between free radicals and the channel wall increases, and the number of free radicals participating in the reaction decreases. When the channel of the flame arrester is narrow to a certain extent, the collision between free radicals and the channel wall dominates. Due to the sharp decrease in the number of free radicals, the reaction cannot continue, that is, the combustion reaction cannot continue to propagate through the flame arrester.
3. The maximum experimental safety gap MESG value, where the flame passes through the small channel of the flame arrester and cools down inside the channel. When the flame is divided to a certain extent, the heat removed through the channel is enough to lower the temperature below the ignition point of the combustible material, causing the flame to extinguish. Or explained by the wall effect, when the channel is narrow to a certain extent, the collision between free radicals and the pipeline wall dominates, and a significant reduction in free radicals prevents the combustion reaction from continuing. Therefore, the channel size that can precisely extinguish the flame under certain conditions (0.1 MPa, 20 ℃) is defined as the Maximum Experimental Safety Gap (MESG). The channel size of flame arresters is a key factor determining their performance, and different gases have different MESG values. Therefore, when selecting a flame arrester, its MESG value should be determined based on the composition of combustible gases. When making specific choices, the gas is divided into several levels based on the MESG value. Currently, two types of methods are commonly used internationally. One is the classification system of the National Electrical Council (NEC) in the United States, which divides gases into four levels (A, B, C, D) based on their MESG values; Another type is the method of the International Electrotechnical Association (IEC), which also divides gases into four levels (IIC, IIB, IIA, and I). The MESG values and test gases for each type of gas divided by two standards are shown in Table 1.
Two classification standards for MESG
NEC | IEC | MESG/MM |
Test gas |
A | IIC | 0. 25 |
acetylene |
B | IIC | 0. 28 |
hydrogen |
C | IIB | 0. 65 |
ethylene |
D | IIA | 0. 90 |
propylene |
G | M I | 1. 12 | methane |
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