冷冻干燥机的真空系统有什么作用

VACUUM SYSTEM真空系统

双级真空泵组冷冻干燥过程中所需要的真空泵及相关阀门组成的真空泵组，真空系统安装在机架上。

真空系统配置包括带有隔离阀的双真空泵并联运行，一旦控制压力达到要求，一台真空泵停止，转为备份。双泵系统在周期中自动切换。

The vacuum pump group composed of vacuum pump and related valves in the freeze-drying process of the two-stage vacuum pump group, the vacuum system is installed on the frame.

Vacuum system configuration includes double vacuum pump with isolation valve running in parallel. Once the control pressure meets the requirements, a vacuum pump stops and is converted to backup. The double pump system switches automatically during the cycle.

真空泵内部的连接和与冷阱的连接通过AISI304L 不锈钢管。真空系统与冷凝器之间使用全自动、气动蝶阀使真空系统与冻干机隔离。如果出现停电事故，阀门自动关闭以防止真空系统污染冷凝器并减少了在恢复来电之前由于压力升高导致的产品损失。每台真空泵在泵进口都安装自动蝶阀，可以确保系统在作为‘备份泵’或停电时有效的隔离。在冷阱的隔离阀与泵之间安装有一个 Pirani 探头。每台泵的进口上都预留带阀门的接口，在系统检查、维护时可以安装Pirani 探头。

Vacuum pump internal connection and cold trap connection through AISI304L stainless steel pipe. The vacuum system and condenser are fully automatic, and the pneumatic butterfly valve separates the vacuum system from the freeze-drying machine. In the event of a power outage, the valve is automatically closed to prevent the vacuum system from polluting the condenser and to reduce the loss of the product due to increased pressure before resuming the incoming call. Each vacuum pump is equipped with an automatic butterfly valve at the inlet of the pump to ensure that the system is effectively isolated as a backup pump or as a power outage. A Pirani probe is installed between the cold trap isolation valve and the pump. The interface with valve is reserved on the inlet of each pump Pirani probe can be installed during system inspection and maintenance.

Vacuum Measurement and Control真空测量和控制

箱体上装有一个真空探头。探头输出信号给PLC 及记录仪，以显示在SCADA 系统上并控制。

真空的自动控制可以根据用户的选择采用两个系统来实现：

• 掺气 -通过调节阀和由PLC 数字输出控制的通断电磁隔离阀以受控的速率向箱体内输入气体（空气或选择的其它气体－通过控制面板可以选择相关阀门）。

• 真空节流- 通过控制安装在冷阱和真空系统之间的真空隔离阀。

The chamber is supplied with a vacuum gauge (see item 26). The gauge output is fed to the PLC for control purposes, recorded on the chart recorder and displayed within the Lyomax Compact system. 

Automatic vacuum control is achieved by either of two systems according to user selection:

•Gas bleed - a gas (air or selected gas – the appropriate valve is selected via the control panel) is fed into the chamber at a rate controlled via a modulating valve (see item 27) and on/off solenoid isolation valve controlled by a digital PLC output. 

•Vacuum throttling - by controlling the vacuum isolation valve installed between the condenser and vacuum system.

Leak Tightness泄漏率

由箱体和冷凝器及相关管路、阀门、入口过滤器（如安装）及仪表组成的系统泄漏率对于不凝性气体，可保持0.03mbarl/s 或更高。

The complete process system comprising chamber, condenser and associated pipework, valves, inlet filters (when fitted) and instruments shall have a leak rate of 0.03mbarl/s or better for non-condensable gases.