How to send nodular cast iron manhole cover for inspection? When the well ring of the nodular cast iron well cover is inspected, a T-shaped sealant strip can be placed at the mouth groove of the inner ring to produce a rubber ring, which can well avoid the running and jumping of the well cover, continue to improve the area between the well cover and the inner city ring, and increase the total area in line with and touched. The surface of nodular cast iron manhole cover adopts the pattern of cross flower edge triangle, which can have a very good practical effect.
How to recheck nodular cast iron manhole cover?
Appearance: no significant welding defects.
2. Check the diameter of the well ring with common tools. The diameter of the operation scope is within the specification of the well cover, with a depth of 40mm. The anchor bolt holes shall be checked one by one with special tooling fixtures.
Fitting and spraying inspection of nodular cast iron manhole cover
1. The T-shaped rubber ring shall be matched with the well ring. The rubber ring shall be flat in the T-shaped groove, not longer or shorter, firmly bonded, and the matching gap shall not exceed mm.
2. The well cover and well frame shall be assembled flat without shaking and noise, and the height of the cover and frame shall not exceed mm.
3. The T-shaped rubber ring shall be firmly adhered before spraying. The well cover (ring) shall be sprayed evenly without rust.
The quality of cast iron well covers is unqualified. Due to various reasons, some fake and shoddy well covers are used in engineering projects, leaving potential safety hazards for safety. At present, in addition to the traditional cast iron manhole covers, nodular cast iron, new concrete and polymer manhole covers are also widely used.
The following are standard specifications for ductile iron manhole covers:
a. The raw material of the well cover is nodular cast iron, the diameter of the well ring is 2mm, the height matching precision of the well cover and the well ring is 1mm, and the matching gap is 3mm.
b. The compressive strength of well ring and well cover exceeds 500N / cubic mm, and the hardness test method is hb190-230. The pressure resistance of well cover meets the national standard requirements of CJ / t3012-93 cast iron inspection well cover of the Ministry of housing and urban rural development. The pressure resistance of super heavy well cover is 360kn and that of light well cover is 210kN.
c. The T-shaped rubber ring is made of EPDM, and the performance parameters are super heavy gb-7529-87 national industry standard.
d. The anti-theft function is carried out according to the way that the fixed shaft of the well base is connected with the well cover, and the other side is fixed with pins. It has solid anti-theft, anti cavitation and ditch cutting.