As essential safety parts for storage tanks, the threaded breather valve and the flanged breather valve differ greatly in valve connection. They balance tank pressure, prevent tank damage and cut medium evaporation. This passage analyzes their distinctions, parameters and applications to guide you to pick proper valves for pipelines and tank systems.
The threaded breathing valve adopts a threaded end connection structure (internal thread or external thread), which can be directly screwed onto threaded pipes and fittings without assembling with flanges, bolts, gaskets, etc. The valve body threads follow common standards such as NPT and BSP, and the thread surface is usually wrapped with sealing tape or coated with sealing agent to improve sealing. This kind of valve is compact in structure, light in weight, has few accessories, and is suitable for small-diameter pipes. ZhenChao threaded breathing valve retains the core functions of pressure balance, anti-freezing, and fire prevention, and is suitable for small storage tanks, medium and low-pressure simple pipeline systems.
The flange breathing valve has a flange plate machined on both ends of the valve body. When installing, align the valve flange with the pipe flange, use bolts and nuts to clamp and fix, and add a gasket between the two flanges to achieve sealing. The ZhenChao flange breathing valve adapts to a variety of flange standards at home and abroad. The valve body is made of thick material, the structure is strong, and the integrated flame arrester and anti-static device can operate stably under harsh conditions. It is the mainstream connection form of large-scale storage tanks and high-pressure petrochemical systems.
Comparison Item | Threaded Breather Valve | Flanged Breather Valve |
Connection Structure | Threaded engagement; no flanges, bolts, or other accessories | Flange + bolt + gasket assembly |
Installation Process | Simple and quick; screws directly into pipe fittings; minimal requirements for tools and personnel | Requires aligning flange holes, positioning gaskets, and tightening bolts to specific torque; a complex procedure |
Space Requirements | Compact size; minimal installation footprint; suitable for tight spaces | Bulky flange and bolt assembly; requires ample surrounding clearance for installation/operation |
Threaded connections rely on thread engagement for fastening, requiring fewer parts and allowing for rapid on-site installation; flanged connections feature a multi-component design that, while involving more installation steps, results in a secure connection and superior overall stability once assembled.
The threaded breathing valve is limited by the strength of the thread and is only suitable for medium and low-pressure conditions. If the pressure is too high, it is easy to cause the thread to deform, loosen, and leak. In terms of temperature, long-term work in extremely high-temperature and extremely low-temperature environments will accelerate the aging of threads and the failure of seals.
The flange breathing valve disperses pressure through the bolt structure, and with different gaskets and valve body materials, it can withstand higher pressure and adapt to a wider temperature range. ZhenChao’s two types of breathing valves have a general environmental temperature of **-40℃ ~ + 60℃**. The flange type can be stably matched with all four pressure levels of the product (A / B / C / D type), and the thread type is usually only matched with the standard B pressure level.
ZhenChao’s two types of breathing valve core sealing parts are made of polytetrafluoroethylene material, which has the characteristics of low temperature resistance and anti-frost, and all are equipped with anti-static devices, so that the valve and the storage tank maintain equal potential, eliminating static electricity hazards.
The valve body can be made of corrosion-resistant materials such as WCB, SS304, SS304L, SS316, and SS316L. The difference in sealing between the two is mainly reflected in the connection part:
Thread connection: The seal relies entirely on the thread and auxiliary sealant. Long-term use or vibration can cause the thread to loosen and create a leakage hazard.
Flange connection: The gasket between the flanges forms a stable sealing surface, is not easily affected by vibration and medium corrosion, has a long-lasting sealing effect, and is safer for gasoline, kerosene and other flammable and explosive volatile media.
After long-term use, the threaded breathing valve is prone to corrosion and causes the thread to bite, and the process of disassembly is very easy to damage the valve and pipe thread. Repeated disassembly will greatly shorten the service life, and after the thread failure, it is usually necessary to replace the whole; later maintenance is difficult.
The flange breathing valve can be removed by loosening the bolts, no need to cut the pipeline, the daily maintenance is mainly to replace the gasket and re-tighten the bolts. The operation is simple and convenient. The flange connection is firm, the valve body is less affected by external forces, the overall service life is longer, and it is suitable for equipment that needs to be inspected and repaired regularly.
Comparison Item | Threaded Breather Valve | Flanged Breather Valve |
Initial Procurement Cost | Low cost; no need to purchase additional flanges, bolts, or gaskets | Higher overall cost; involves many accessories and high labor costs for installation |
Long-term Maintenance Cost | Threads are prone to damage; replacement costs are high | Gaskets are low-cost, consumable parts; maintenance costs are low |
Compatible Pipe Diameter | Small-diameter piping | Covers all sizes; preferred choice for large-diameter main pipelines |
Henchao ZCPE is a leading diaphragm with a flame arrester, which integrates pressure balance, flame arrester, and anti-freezing into one, and the working pressure is divided into four specifications:
Type A: Positive pressure + 355 Pa (+36 mm water column), negative pressure – 295 Pa (-30 mm water column)
Type B: Positive pressure + 980 Pa (+100 mm water column), negative pressure – 295 Pa (-30 mm water column) (standard working pressure of the product)
Type C: Positive pressure + 195 Pa (+200 mm water column), negative pressure – 295 Pa (-30 mm water column)
Type D: Customized special pressure level according to user needs
·Basic parameters
Operating environment temperature: -40 ℃ ~ +60 ℃
Optional materials: WCB, SS304, SS304L, SS316, SS316L; The casing can be made of HT, AL, A3, etc.
Applicable media: Gasoline, kerosene, diesel, aromatics, sulfur, air and other petrochemical media
Additional functions: Anti-freezing, anti-static, fire-proof and explosion-proof, low leakage of valve seat, and full flow pressure relief.
Flange standard: HG / T20592 – 2009, HG / T2 0615 – 200 9, ANSI B16.5; At the same time, it can be customized according to user-specified standards such as HG20529-97 PN10.
Threaded breathing valve applicable scenarios: small storage tanks, laboratory auxiliary pipes, building HVAC systems, small-diameter sampling pipes and drainage pipes in petrochemical plants. In such scenarios, the pressure is low, the pipe diameter is small, the installation space is limited, and the frequency of equipment inspection is low.
Flange breathing valve applicable scenarios: large oil storage tanks, chemical raw materials storage tanks, power generation supporting equipment, and large and medium petrochemical pipelines. The medium of this kind of scene is flammable and explosive, corrosive, with high pressure and large pipe diameter, and the equipment needs to be inspected regularly, with extremely high requirements for the firmness of connection and the reliability of sealing.
To decide whether to choose a threaded breathing valve or a flange breathing valve, you need to consider the following four points comprehensively:
Work pressure and temperature: in situations of medium and high pressure, large temperature changes, and obvious heat cycles, prefer to use flange breathing valve; The threaded version is available for small systems at low pressure and room temperature.
Pipe diameter and installation space: for small-diameter pipes and narrow installation spaces, use threaded connections; The main pipeline with a large diameter and sufficient surrounding operating space adopts a flange connection.
Medium characteristics: transporting gasoline, diesel and other flammable, explosive, volatile and corrosive petrochemical media, it is recommended to choose a flange breathing valve with better sealing and stability to avoid leakage risks.
Inspection cycle: when the equipment needs frequent disassembly, inspection and maintenance, it is preferred to use the easy-to-disassemble flange breathing valve; Pipes with long-term fixed installation and minimal maintenance can use threaded valves to save costs.
When ordering threaded breathing valves, please confirm the thread standard of the on-site pipeline (NPT/BSP) to avoid thread mismatch and assembly failure.
When ordering a flange breathing valve, specify the flange standard (HG/T series or ANSI B1.6.5), pressure grade, and nominal diameter. ZhenChao supports customization of various types of flange standards at home and abroad, ensuring seamless connection with on-site pipelines.
For special working conditions such as low temperature and strong corrosion, communicate with the manufacturer in advance to select suitable valve body material and sealing accessories.
Q1: What is the main difference between a threaded breathing valve and a flanged breathing valve?
A1: The core difference is the valve connection method. The threaded version is small, cheap, and easy to install; The flange version has higher strength, better sealing performance, and better maintainability.
Q2: Which type of breathing valve is more suitable for high-pressure oil storage tanks?
A2: The flange breathing valve is preferred for high-pressure oil storage tanks.
Q3: Which flange standards does the ZhenChao flange breathing valve follow?
A3: Products comply with the standards of HG/T22059-2009, HG/T2615-22009, ANSI B16.5, etc., and can also be customized as needed.
Q4: What is the applicable working temperature range of the ZhenChao breathing valve?
A4: The applicable temperature range is -40 ℃ ~ +60 ℃.
Q5: Which type of breathing valve is easier to maintain on a daily basis?
A5: The daily maintenance of the flange breathing valve is simpler and more convenient.
Threaded and flanged breather valves apply to different working conditions. The ZCPE series from ZhenChao includes both connection types with full specifications and multiple functions. Choose matching products based on actual needs to guarantee safe and efficient system operation.
