Shenzhen Wofly Technology Co., Ltd.

Gas flashback and flashback combustion are highly dangerous accident types in industrial gas operations, which can cause equipment damage at best and trigger explosions to threaten personnel safety at worst. Statistics show that 80% of flashback incidents are caused by human operational errors, while material defects and improper gas pressure regulation are also major contributing factors.   When flashback combustion occurs, the flame will rush back toward the welding torch accompanied by popping sounds and whistle-like noises. If not handled promptly in the initial stage, the flame will penetrate the welding torch and directly reach the mixing zone of fuel gas and oxygen. Even more dangerous is the flashback caused by gas backflow: high-pressure gas will flow into low-pressure hoses to form a mixed gas. Once ignited by flashback, the flame will spread along the hoses at twice the speed of sound, leaving operators with no time for manual intervention. This can easily lead to hose rupture, pressure regulator ignition, and in extreme cases, explosion of high-pressure gas cylinders or storage tanks. Fuel gas itself is not a "menace"; it is controllable and safe for professional operators. However, incorrect usage methods will amplify risks. To fundamentally avoid gas flashback hazards, it is crucial to correctly understand safety specifications and equip with dedicated protective devices. Gas safety equipment such as flashback arresters and flame arresters are the "safety guardians" in industrial gas operations.   Flashback arresters and flame arresters are widely used in industrial processes such as oxy-fuel welding and cutting. Their core function is to block the spread of flames or backflow gas to equipment and supply pipelines, building a safety barrier for operators and equipment, and serving as essential devices to ensure the safety of the working environment. The protection principle of flame arresters is mainly based on two core mechanisms: heat transfer effect and wall effect:   Heat Transfer Effect : A necessary condition for combustion is that the temperature reaches the ignition point of the combustible material. Below the ignition point, combustion will stop. Based on this principle, the spread of flames can be prevented as long as the temperature of the combustion material is reduced below its ignition point. When flames pass through the numerous tiny channels of the flame arrester element, they are divided into many small flames. In designing the internal flame arrester element, the contact area between the small flames and the channel walls is maximized to enhance heat transfer, thereby rapidly lowering the flame temperature below the ignition point and terminating combustion immediately.   Wall Effect:Combustion and explosion are not direct reactions between molecules, but rather involve the excitation of molecules by external energy, which breaks molecular bonds to generate activated molecules. These activated molecules further decompose into short-lived but highly reactive free radicals. When free radicals collide with other molecules, new products are formed, and new free radicals are generated to continue reacting with other molecules. When combustible gas passes through the narrow channels of the flame arrester, the collision probability of free radicals with the channel walls increases significantly, reducing the number of free radicals participating in the reaction. When the channels of the flame arrester are narrow enough, collisions between free radicals and channel walls become dominant. Due to the sharp reduction in the number of free radicals, the reaction cannot proceed, meaning the combustion reaction cannot spread through the flame arrester.   As dedicated safety devices to prevent the spread of flames from flammable and explosive gases and guard against flashback explosions, flame arresters are usually installed on storage tanks and pipelines that transport or discharge flammable and explosive gases. They can not only prevent external flames from rushing into equipment and pipelines but also block the spread of flames between equipment and pipelines, building a solid line of defense for industrial gas operations.

Though differing by only one word in Chinese, these two are distinct types of pressure measuring instruments with significant disparities in structure, working principle, applicable media and operating conditions.   Diaphragm Capsule Pressure Gauge Its appearance is basically the same as that of a Bourdon tube pressure gauge, but its pressure-sensing element is an elastic sensitive component called a diaphragm capsule. The capsule is formed by welding two circular corrugated diaphragms together. When the pressure of the measured medium acts on the capsule, elastic deformation occurs inside it, causing its free end to displace. This displacement is then amplified by a gear transmission mechanism, and the measured pressure value is indicated by a pointer on the dial. Diaphragm Capsule Pressure Gauge: The corrugated small capsule expands directly to drive the pointer, and it can only measure gases.   Structurally, it consists of four parts: Measuring system (connector, diaphragm capsule element, etc.) Transmission mechanism (lever mechanism, gear transmission mechanism) Indicating components (pointer, dial) Enclosure (case, gasket, and sight glass) It features a relatively simple structure, excellent seismic performance and good temperature adaptability. Diaphragm Seal Pressure Gauge It is a system composed of a diaphragm isolator, a general-purpose pressure gauge (e.g., Bourdon tube pressure gauge) and a sealed filling fluid. The diaphragm isolator serves to isolate the measured medium from the pressure-sensing element of the gauge. When the pressure of the measured medium acts on the diaphragm, the diaphragm deforms and compresses the sealed filling fluid in the closed system. The transmission effect of the fluid causes the elastic element (such as a Bourdon tube) inside the gauge to produce corresponding elastic deformation, thereby indicating the pressure of the measured medium. The diaphragm (which acts like a drumhead) senses pressure and transmits it to the pointer via a liquid.   Its structure is relatively complex, but it boasts outstanding corrosion resistance. It can prevent the measured medium from directly entering the general-purpose pressure gauge, avoiding sediment accumulation and enabling easy cleaning. Applicable Media and Operating Conditions Diaphragm Capsule Pressure Gauge It is suitable for measuring micro-pressure and negative-pressure gases that are non-corrosive to copper alloys and non-explosive. It is widely used in equipment such as boiler ventilation systems, gas pipelines and combustion devices. It offers high measurement accuracy, with a typical measuring range of 0.001 MPa to 4 MPa. It is capable of measuring both micro-pressure and negative-pressure values, thanks to its simple structural design. Diaphragm Seal Pressure Gauge It is designed for media with strong corrosiveness, high temperature, high viscosity, crystallization tendency, solidification tendency or containing solid suspended particles. It is commonly used in industrial sectors including petrochemicals, caustic soda production, chemical fiber manufacturing, dye chemical engineering, pharmaceuticals, food processing and dairy making. Its measuring range generally spans 0.1 MPa to 40 MPa. Isolation diaphragms made of different materials can be selected according to specific application scenarios and media properties. Summary   Diaphragm capsule pressure gauges and diaphragm seal pressure gauges each have unique characteristics to meet different measurement requirements. The former is mainly used for high-precision measurement of micro-pressure and negative pressure, while the latter is suitable for measuring the pressure of complex media such as strongly corrosive, high-viscosity and crystallizable fluids. Users can select the appropria

When the system requires automated control, rapid response, safety protection, special medium handling or space constraints, solenoid valves are the best choice. When selecting the type, a comprehensive judgment should be made in combination with control requirements, working condition parameters (pressure/temperature/medium), and installation conditions.   Parameter Category Key Parameters Selection Guidelines Fluid Characteristics Medium Type Gases/liquids/steam/corrosive media determine valve body material Medium Temperature Standard (-20~80℃), high-temperature (>150℃), low-temperature (20cSt requires large-bore or pilot-operated structure to prevent spool jamming Medium Cleanliness Particulate-containing media need filters (≥80μm) or piston-type structure Operating Conditions Operating Pressure Minimum/maximum operating pressure (e.g., 0~1.6MPa) must match valve rated pressure Operating Voltage AC220V/DC24V (industrial mainstream) must match control system Environmental Conditions Temperature (-30~60℃), humidity (

As a core fluid control component, needle valve material selection directly affects system reliability, service life, and operational costs. Used in scenarios from engine injectors to deep-sea oil extraction, it requires a systematic framework based on four core factors: medium characteristics, operating conditions, economic efficiency, and processability. 1. Medium Corrosiveness This is the primary consideration. In H₂S-containing acidic environments, 304 stainless steel fails in 6 months, while Hastelloy C-276 offers 10x better corrosion resistance and a 3+ year lifespan. For chloride media (e.g., seawater), duplex stainless steel 2205 resists stress corrosion 3x better than 316L, making it ideal for marine use.   2. Temperature & Pressure High-temperature (350℃) and high-pressure (25MPa) supercritical CO₂ systems cause carbon steel creep; Inconel 625 (yield strength ≥415MPa at 650℃) solves this. At -40℃, 304 stainless steel loses 50% toughness, but 304L (ultra-low carbon) works reliably at -196℃ for LNG systems. 3. Wear & Erosion For media with 0.5% quartz sand, cemented carbide (WC-Co, HRA90) valve seats boost wear resistance 20x vs. stainless steel, extending life to 5+ years. Stellite alloy (HRC45) balances hardness and toughness for gas-liquid two-phase flows (e.g., steam turbines).   4. Economy & Processability Brass (1/3 cost of stainless steel) dominates civil heating (80% market share). Hastelloy, though 5x pricier, cuts lifecycle costs by 40% for chemicals. Titanium’s poor machinability (3x tool wear) limits its use. Decision-Making & Future Trends Data-driven models (integrating 20+ parameters, FEA, LCCA) optimize choices—e.g., super duplex 2507 outperforms traditional materials by 35% for deep-sea extraction. Additive manufacturing will enable functionally graded materials (e.g., tungsten carbide-coated seats), shifting selection from "passive adaptation" to "active design."