DA21F低温安全阀工作原理：

        DA21F低温安全阀主要用于液氧（液氮、液氩 天然气）等低温液态介质系统上，具有启动自如、密封稳定、起跳压力稳定等特点。低温微启式安全阀是指用于低温系统上，启闭件受外力作用下处于常闭状态，当低温设备或管道内的低温介质压力升高超过规定值时，通过向系统外排放来防止低温管道或设备内介质压力超过规定数值的阀门。控制低温介质不超过规定值，对人身安全和设备运行起重要保护作用。

低温安全阀

低温安全阀是安装在低温压力容器（如LNG储罐、低温杜瓦瓶）或管道系统上的安全保护装置。其核心功能是当系统压力异常升高超过预定设定值时，自动开启并全额排放超压介质（如LNG、液氮、液氧等），当压力恢复正常后自动关闭，从而防止系统因过压而发生爆炸或损坏，保障生命和财产安全。它是低温系统中不可或缺的关键安全部件。

低温安全阀核心特点：

超低温材料与设计：阀体、阀座、弹簧等主要部件采用深冷处理过的奥氏体不锈钢等材料，能在-196°C及以下的极端低温环境中材料的韧性，避免脆性断裂，并确保动作稳定性。

全启式结构：通常采用全启式（Full Lift）设计，一旦开启，阀瓣迅速达到升程，排放面积大，能快速、大量地泄放压力，有效保护容器。

低温安全阀绝热与防冰设计：采用长颈阀盖（Extended Bonnet）结构，使弹簧和导向机构远离低温流体，保持其处于相对较高的环境温度下，防止因结冰导致阀门无法正常开启或关闭。

金属对金属密封：主密封面通常采用硬质合金（如Stellite） overlay，确保在低温下具有很好的密封性能和耐用性，实现气泡级紧密关闭（Bubble-tight Shut-off）。

低温安全阀背压平衡能力：可选波纹管（Bellows）密封式结构，能平衡背压（Back Pressure）影响，保持稳定的开启压力设定值，适用于排放至封闭系统的工况。

低温安全阀典型应用：

LNG储罐及运输设备：固定式LNG储罐、LNG槽车、LNG船舶燃料罐。

低温安全阀空分设备：液氧、液氮、液氩储罐及系统管道。

低温安全阀液化气体储运：液态二氧化碳、液态乙烯等介质的储罐和管道。

低温气化系统：LNG气化器、空温式气化器的出口管道保护。

Product Overview of Cryogenic Safety Valves

A Cryogenic Safety Valve ( Cryogenic Relief Valve) is the ultimate safety protection device installed on cryogenic pressure vessels (e.g., LNG storage tanks, cryogenic dewars) piping systems. Its core function is to automatically open fully discharge over-pressurized media (e.g., LNG, liquid nitrogen, liquid oxygen) when the system pressure abnormally rises beyond a predetermined set value. It recloses automatically once pressure normalizes, thereby preventing system explosion damage due to overpressure safeguarding life property. It is an indispensable critical safety component in any cryogenic system.

Key Features:

Cryogenic Materials Design: Primary components like the body, seat, spring are made materials such as deep-cryo treated austenitic stainless steel. This ensures material toughness avoids brittle fracture at extreme temperatures down to -196°C below, guaranteeing operational reliability.

Full-Lift Design: Typically employs a Full-Lift design. Upon opening, the disc rapidly reaches maximum lift, providing a large discharge area for rapid substantial pressure relief, effectively protecting the vessel.

Thermal Insulation Ice Prevention: Features an Extended Bonnet structure that positions the spring guiding mechanism away the cryogenic fluid. This keeps them at a relatively higher ambient temperature, preventing failure to open close due to ice formation.

Metal-to-Metal Sealing: The primary sealing surface often uses hard-faced alloys (e.g., Stellite overlay), ensuring excellent sealing performance durability at cryogenic temperatures, achieving Bubble-tight Shut-off.

Balanced Backpressure Capability: Optional Bellows-sealed design balances the effects of backpressure, maintaining a stable set opening pressure. This is suitable for applications discharging into a closed system.

Typical Applications:

LNG Storage Transport Equipment: Stationary LNG storage tanks, LNG tanker trucks, LNG ship fuel tanks.

Air Separation Plants: Liquid oxygen, liquid nitrogen, liquid argon storage tanks system piping.

Liquefied Gas Storage Transport: Storage tanks piping for media like liquid carbon dioxide liquid ethylene.

Cryogenic Vaporization Systems: Protection for outlet piping of LNG vaporizers ambient air vaporizers.