Manhole

The manhole has a molded product and is usually 600 mm in diameter. The center of the manhole is generally 750 mm from the floor. It is convenient for workers to enter or exit the tank or ventilate during installation, cleaning and maintenance.

The manhole of the non-metallic oil tank is placed on the top of the tank, and the manhole of the metal oil tank is placed on the lowermost 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. It is used for tank cleaning or maintenance personnel to enter and exit the oil tank, also known as the gate. At the same time, the manhole is used for lighting and ventilation. When the capacity of the vertical tank is below 5000 m3, 1 to 2 individual holes are provided, and for the 5000 m3 or more, 2 individual holes are provided. The installation of the manhole should be no more than 90° from the inlet and outlet lines. When only one manhole is provided, it should be placed opposite the light transmission hole on the top of the tank; when two holes are provided, one of them should be placed opposite the light transmission hole, and the other should be at least 90 apart from the first personal hole. °.

The manhole should be located near the right side of the inlet and outlet pipes, and try to make the manholes close the door to the tank, so that the personnel can enter and exit, repair the oil tank and vent the nozzle.

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 the straightness and no whirling phenomenon. Reinforced plates and flanges should be cut as much as possible on the entire steel plate without splicing. Sealing rings are machined on the flanges and cover plates, so pay special attention to protection during construction. Sealed with 3mm thick asbestos rubber gasket, no cracking is allowed. When tightening the bolts on the manhole cover, evenly apply a force to the diagonal to prevent the hole cover from deforming.