Why is a vent valve installed on the Chengya distillation apparatus?

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Why is a vent valve installed in a vacuum distillation unit? The pumping capacity of a vacuum pump remains constant; it can remove a certain volume of gas per second, thereby maintaining a specific residual pressure within the unit. However, during vacuum distillation, only the desired residual pressure is usually selected, without the need to reach the minimum residual pressure that the vacuum pump can achieve. Therefore, a vent valve should be installed on the buffer bottle; during operation, it is sufficient to slightly open the stopcock to allow some gas to enter from the outside, so as to adjust the residual pressure to the desired level and prevent the vacuum in the device from becoming too high. It also makes it easier to slowly open the vent valve after distillation is complete in order to remove the vacuum, thereby avoiding the adverse effects caused by sudden changes in pressure inside the bottle. Which facilitates safe operation.