Plan 53A
采用外部气体对隔离液储罐加压，隔离液压力始终高于密封腔压力，依靠内置泵送环或热虹吸驱动循环，为双端面密封提供清洁的隔离液和连续冷却。
External gas pressurizes the barrier fluid reservoir with pressure always above seal chamber pressure. Circulation is driven by integral pumping ring or thermo-siphon, providing clean barrier fluid and continuous cooling for dual seals.
产品介绍 / Description
Plan 53A 是 API 682 标准中定义的加压隔离液系统，适用于双端面承压密封（双重密封）。系统通过外部气源（通常为氮气）对隔离液储罐顶部直接加压，使隔离液压力始终高于密封腔介质压力，即使内侧密封失效，介质也不会泄漏至大气。
隔离液循环依靠密封腔内自带的内置泵送环（或热虹吸效应）驱动，无需外部动力泵：隔离液从储罐流出→流经密封腔带走热量→返回储罐。储罐配备冷却盘管进行散热，保证隔离液温度在合理范围内。
该系统结构简单、可靠性高，广泛用于炼油、石化、化工等领域，尤其适合轻质烃类、液化气、有毒有害介质，以及易聚合、含固体颗粒的脏介质等工况。
**注意：隔离液压力上限为 16 bar，超过此限值应选用 Plan 53B 或 53C。可采用孔板防止内侧泄漏时大量气体进入密封腔。**
Plan 53A is a pressurized barrier fluid system defined in API 682, suitable for dual pressurized mechanical seals (double seals). The system uses an external gas source (typically nitrogen) to directly pressurize the top of the barrier fluid reservoir, maintaining barrier fluid pressure always above seal chamber pressure. Even in the event of inner seal failure, the process fluid will not leak to atmosphere.
Barrier fluid circulation is driven by the integral pumping ring (or thermo-siphon effect) within the seal chamber, requiring no external power pump: the barrier fluid flows from the reservoir → passes through the seal chamber to remove heat → returns to the reservoir. The reservoir is equipped with a cooling coil for effective heat dissipation, keeping the barrier fluid temperature within a reasonable range.
The system features simple construction and high reliability, widely used in refining, petrochemical, and chemical industries. It is particularly suitable for light hydrocarbons, LPG, toxic and hazardous fluids, as well as polymerizing fluids and dirty media containing solid particles.
**Note: The maximum barrier fluid pressure is 16 bar; above this limit, Plan 53B or 53C should be selected. An orifice may be used to prevent excessive gas ingress into the seal chamber in case of inner seal leakage.**
技术规格 / Technical Specifications
技术参数 / Working Condition
| 密封腔压力 Seal Chamber Pressure | ≤ 16 bar |
|---|---|
| 隔离液压力差 Barrier Fluid Differential Pressure | ≥ 1.4 bar（高于密封腔压力） ≥ 1.4 bar (above seal chamber pressure) |
| 适用场景 Application Scenarios | 轻质烃类、液化气、有毒有害、易聚合、含固体颗粒的脏介质 Light hydrocarbons, LPG, toxic/hazardous, polymerizing, dirty/solid-laden fluids |
系统配置 / System Configuration
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立式加压隔离液储罐（带冷却盘管、液位计、压力表、充气阀、排气阀） Vertical pressurized barrier fluid reservoir (with cooling coil, level gauge, pressure gauge, fill valve, vent valve)
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手动补液泵（选配） Manual refill pump (optional)
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循环泵（选配，用于增强或替代内置泵送环） Circulation pump (optional, for enhanced circulation or as alternative to integral pumping ring)
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外部气体调节器（减压阀） External gas regulator (pressure reducing valve)
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压力开关/压力变送器（泄漏监测及低压报警） Pressure switch / pressure transmitter (for leakage monitoring and low pressure alarm)
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液位开关/液位计（隔离液补充指示） Level switch / level gauge (for barrier fluid make-up indication)
产品特性 / Features
- 封液必须与泵送介质相容；系统运行前充分排气 Barrier fluid must be compatible with pumped fluid; vent system thoroughly prior to operation
- 封液压力至少高于密封腔压力 1.4 bar，最大 16 bar Barrier fluid pressure must be at least 1.4 bar above seal chamber pressure, maximum 16 bar
- 超过 16 bar 请选用 Plan 53B / 53C / 54 For pressures above 16 bar, use Plan 53B / 53C / 54
- 可采用孔板防止内侧泄漏时大量气体进入密封腔 An orifice may be used to prevent excessive gas ingress into the seal chamber in case of inner seal leakage