根据管子类别，决定温度计套管是用法兰连接还是螺丝连接。
Choice between flanged and screwed thermowells will be governed by the pipe classification .
把四个前面板螺丝和两个顶部法兰上的螺丝卸下来。检验排水阀，确保排水阀处于关闭状态。
Remove the four front panel screws ; two at the top flange . Check drain valve to make sure that it is closed .
法兰螺丝