| 摘要 |
PURPOSE:To obviate the generation of clogging even if raw material in gaseous phase is liquefied again in the brach pipes by installing a sensor branch pipe and a bypass branch pipe constituting a branch circuit so as to incline in a vertical direction. CONSTITUTION:The mid-way of a pipe 5 to be connected to a gas supply source 6 is branched to two ways to constitute a branch circuit 3 consisting of a sensor branch pipe 1 and a bypass branch pipe 2. A measurement section 6 which generates a signal according to the change in the mass of the gas flowing in the pipe 1 is provided to said pipe. The pipes 1, 2 are so installed as to incline in a vertical direction B in such an installing method of the thermal mass flow controller. As a result, even if the raw material in gaseous phase is liquefied again in the pipes 1, 2, the liquid flows from the branch pipe by gravity and therefore the generation of clogging is obviated, hence the usable period is considerably extended. Since the need for washing, regeneration, etc. of the branch pipe is eliminated, the reduction of the cost required for the same is made possible. |
