Technical requirements for manhole cover
Well covers are used to cover roads or deep wells in homes to prevent people or objects from falling. According to the material, it can be divided into metal, high-strength fiber, cement concrete, resin, etc. Generally, circular is used. It can be used in green belts, sidewalks, motorways, docks, alleys, etc. Next, let’s learn about the technical requirements of inspection well cover.
1. The raw materials for manufacturing inspection well covers and other products shall be QT500-7 nodular cast iron, with spheroidization rate greater than 90, spheroidization grade above grade 3, phosphorus content < 0.08 and sulfur content < 0.05.
2. The surface of well cover and well seat shall be cast flat and bright, with clear patterns, marks and words, without defects, redundant parts, burrs, sharp edges, warpage, cracks, cracks or defects such as cold shut, bulge, sand hole and shrinkage hole affecting the service performance of inspection well. Repair welding is not allowed.
3. The well cover shall adopt socket structure to make the lower part of the derrick closely fit with the inner wall of the well body; A three-point spring arm locking device shall be used to prevent accidental opening, stability, jumping and displacement, greatly reduce the vibration caused by impact, greatly reduce the possibility of crushing the surrounding road surface, and prevent noise. The protective hinge to prevent accidental closing shall be adopted. The hinge shaft shall be stainless steel hinge shaft with a diameter of no less than 14 mm to make the connection more firm and hidden under the flange panel as a whole, so as to improve the anti-theft performance.
4. The joint width between the well cover and the well seat shall meet the following requirements: check the net width JKMM ≥ 600, the joint width a = a1 + a2mm, and the allowable deviation range 8 + 2-4; Check that the net width JKMM < 600, the seam width a = a1 + a2mm, and the allowable deviation range is 6 ± 2.
5. The width of the bearing surface of the well seat shall meet the following requirements:
(1) Check the clear width JKMM ≥ 600 and the bearing surface width of well seat 6mm ≥ 20; The clear width of manhole cover JKMM < 600 and the width of bearing surface of support 6mm ≥ 15.
(2) Heavy inspection well, the buried depth of well cover shall not be less than 40mm, and the anti-skid pattern: the raised height is 3mm.