Stainless steel manhole:
It is a safety emergency ventilation device installed on the top of storage tank. It is usually used with fireproof device and mechanical breathing valve. It can not only avoid accidents caused by sudden overpressure or vacuum in the tank due to unexpected reasons, but also play a role of safety fire resistance. It is a safety device for protecting storage tank, especially for storing materials. Atmospheric vault tank with nitrogen seal roof. The utility model has the advantages of constant pressure discharge, constant pressure inhalation, flexible opening and closing, safe fire resistance, compact structure, good sealing performance, safety and reliability, etc.
Stainless steel manholes are usually made of 304 and 316L steel plates as raw materials.
Manhole is divided into emergency relief manhole, explosion-proof and fire-proof breathing manhole, manhole on tank top, manhole on tank wall and manhole with core, etc.
Manhole has been moulded with a diameter of 600 mm. The center of manhole is 750 mm from floor. It is convenient for staff to enter and exit oil tanks and ventilate during installation, cleaning and maintenance.
The manholes of the non-metallic oil tank are arranged on the top of the tank, and the manholes of the metal oil tank are arranged on the lower ring plate of the tank wall. Most of them are round holes with a diameter of 600 mm, the center of which is 750 mm away from the bottom plate. They are used for tank cleaning or maintenance personnel to enter and exit the tank, also known as doors. Manhole is used for lighting and ventilation when oil tank is repaired and cleaned. The capacity of the vertical tank is 5000 m_and there are 1 to 2 manholes below and 2 manholes above 5000 m_. The installation of manhole should be no more than 90 degrees apart from the oil pipeline. When only one hole is set, it should be placed opposite the transparent hole on the top of the tank; when two holes are set, one of them is located opposite the transparent hole and the other should be at least 90 degrees away from the individual hole.
The manhole shall be located near the right side of the exit and exit tubing, and the manhole shall be as close as possible to the closed door of the tank room so that personnel can enter and exit, repair the tank and ventilate the nozzle.
Because the manhole is installed on the lower body ring of the oil tank, leakage prevention is particularly important. It is required that the flange joint should be flatness and free from drift and torsion. Strengthened plate and flange should be cut on the whole steel plate as far as possible without splicing. Flanges and cover plates are machined with sealing rings, so special attention should be paid to their protection in construction. Sealing with 3 mm thick asbestos rubber gasket, no cracking allowed. When tightening the bolts on the manhole cover plate, the bolts should be diagonally and forcefully installed to prevent the deformation of the manhole cover.