The manhole is a safety emergency ventilation device in […]
The manhole is a safety emergency ventilation device installed on the top of the beer equipment storage tank. It is used in conjunction with the mechanical breathing valve, which can not only avoid accidents caused by sudden overpressure in the tank or damage the storage tank due to vacuum, but also play a role in preventing accidents. It is a safety device to protect the storage tank, especially suitable for the vaulted atmospheric pressure tank whose storage material is capped with nitrogen. It has the advantages of constant pressure discharge, constant pressure suction, flexible opening and closing, safe fire resistance, compact structure, good sealing performance, safety and reliability.
Manholes have formed products, usually 600mm in diameter. The center of the manhole is generally 750mm from the floor. It is convenient for staff to enter and exit the oil tank and ventilation during installation, cleaning and maintenance.
The manhole of the non-metal oil tank is set on the top of the tank, and the manhole of the metal oil tank is set on the lowermost ring plate of the tank wall. Most of them are round holes with a diameter of 600mm, the center of which is 750mm from the bottom plate, which is used for tank cleaning or maintenance personnel to enter and exit the tank, also known as the door. Always use manholes for lighting and ventilation during maintenance and cleaning of oil tanks. When the capacity of the vertical oil tank is less than 5000m3, there are 1~2 manholes, and if the capacity is more than 5000m3, there are 2 manholes. The installation of the manhole should be no more than 90° away from the oil inlet and outlet pipelines. When there is only one manhole, it should be placed opposite the light-transmitting hole on the tank top; when two manholes are set, one of them should be located opposite the light-transmitting hole, and the other should be at least 90 degrees apart from the first manhole.
There should be a manhole near the right side of the oil inlet and outlet pipes, and try to make the manhole face the closed door of the tank room, so that personnel can enter and exit, repair the oil tank and the ventilation pipe.
Since the manhole is installed on the lowermost body ring of the oil tank, leakage prevention is particularly important. It is required that the joint surface of the two flanges must ensure its straightness and no floating twist phenomenon. The reinforcement plate and flange should be cut on the whole steel plate as far as possible without splicing. There are sealing rings on the flange and cover plate, and special attention should be paid to protection during construction. 3mm thick asbestos rubber gasket is used for sealing, no cracking is allowed. When installing the tightening bolts on the manhole cover, apply force in pairs to prevent the hole cover from being deformed.