Can the exhaust air outside the wall be fitted without a check valve?
The backflow valve of the exhaust fan is usually installed. It is a method to prevent the air flow from returning to the fan when it is stoppedIf your fan is just outside the wall, you can't install it,But if it is a blast of contaminated air or a dilution of dangerous air flow, it is better to have it installedCheck valve refers to rely on the flow of the media itself and automatically open and close the valve flap, used to prevent media backflow valve, also known as check valve, one-way valve, counter flow valve, and back pressure valve.
What you are talking about is the backflow blower of the exhaust fan. This is usually installed. It is a method of preventing the air stream from returning under the condition that the fan stops running. If your fan is only a common wall exhaust, you can not install it, but if it is a discharge of air pollution or dilution of dangerous air flow, then advise you to install it as well.
The check valve belongs to an automatic valve, whose main function is to prevent the backflow of medium, prevent the reverse of pump and drive motor, and release the container mediumThe installation of check valves (Check, Valve) shall pay attention to the following items:A do not allow the check valve to bear weight in the line, and the large check valve shall be independently supported so as not to be affected by the pressure generated by the piping system.B, when installing, pay attention to the direction of the flow of medium should be in accordance with the direction of the body marked arrow.C and vertical vertical check valves shall be installed on the vertical pipe.D and lift type horizontal check valves shall be installed on horizontal pipes