basic knowledge of stainless steel manholes

Manholes have formed products, usually with a diameter of 600mm. The distance between the center of the manhole and the floor is generally 750mm. It is convenient for workers to enter and exit the oil tank and ventilate during installation, cleaning and maintenance. The manhole of non-metallic oil tanks is located on the top of the tank, and the manhole of metal oil tanks is located on the bottom ring plate of the tank wall. Most of them are round holes with a diameter of 600mm, and their center is 750mm from the bottom plate. They are used for tank cleaning or maintenance personnel to enter and exit the tank. They are also called doorways. During maintenance and cleaning of oil tanks, manholes are always used for lighting and ventilation. Vertical oil tanks with a capacity of less than 5000 m are provided with 1 to 2 manholes, and those with a capacity of 5000 m or more are equipped with 2 manholes. The manhole should be installed no more than 90° away from the inlet and outlet oil pipelines. When only one manhole is provided, it should be placed opposite the light-transmitting hole on the tank top; when two manholes are provided, one of them should be located opposite the light-transmitting hole, and the other should be at least 90 meters away from the first manhole. °. There should be one manhole located near the right side of the oil inlet and outlet pipe, and try to make the manhole facing the closed door of the tank room to facilitate personnel entry and exit, maintenance of the oil tank and ventilation pipe. Since the manhole is installed on the lowest body ring of the oil tank, leakage prevention is particularly important. It is required that the joint surface of the two flanges must be straight and free of twisting. The reinforcing plate and flange should be cut on the entire steel plate as much as possible without splicing. The flange and cover plate are processed with sealing rings, so special attention should be paid to their protection during construction. Use 3mm thick asbestos rubber gasket for sealing, no cracking is allowed. When installing the manhole cover and tightening the bolts, apply force evenly and diagonally to prevent the manhole cover from deforming.