Manhole inserts

Abstract

Manhole inserts suitable for deployment in a manhole opening of a manhole structure may include a manhole insert bottom. A manhole insert sidewall may extend from the manhole insert bottom. A manhole insert flange may extend from the manhole insert sidewall. A manhole insert gasket may be on the manhole insert flange, The manhole insert gasket may include a solidified, hardened, and cured gasket material having a synthetic silicone elastomer. The manhole insert gasket may be configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.

What is claimed is: 
     
         1 . A manhole insert suitable for deployment in a manhole opening of a manhole structure. comprising:
 a manhole insert bottom;   a manhole insert sidewall extending from the manhole insert bottom   a manhole insert flange extending from the manhole insert sidewall; and   a manhole insert gasket on the manhole insert flange and comprising a solidified, hardened, and cured gasket material comprising a synthetic silicone elastomer, the manhole insert gasket configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.   
     
     
         2 . The manhole insert of  claim 1  wherein the manhole insert gasket comprises at least one annular gasket cord. 
     
     
         3 . The manhole insert of  claim 2  wherein the at least one annular gasket cord has a semicircular cross-section. 
     
     
         4 . The manhole insert of  claim 2  wherein the at least one annular gasket cam has a gasket thickness of 1.59 mm. 
     
     
         5 . The manhole insert of  claim 2  wherein the at least one annular gasket cord comprises an inner gasket cord and an outer gasket cord. 
     
     
         6 . The manhole insert of  claim 5  further comprising an annular inner gasket space between the manhole insert sidewall and the inner gasket cord and an annular middle gasket space between the inner gasket cord and the outer gasket cord. 
     
     
         7 . The manhole insert of  claim 6  wherein the middle gasket space has a middle gasket space width of 7 mm. 
     
     
         8 . The manhole insert of  claim 1  wherein the synthetic silicone elastomer has a tensile strength of 335 psi and an elongation of from 400% to 600%. 
     
     
         9 . A manhole insert suitable for deployment in a manhole opening of a manhole structure, comprising:
 a manhole insert bottom;   a manhole insert sidewall extending from the manhole insert bottom;   a manhole insert flange extending from the manhole insert sidewall; and   a manhole insert gasket having a discrete annular inner gasket cord on the manhole insert flange and a discrete annular outer gasket cord on the manhole insert flange in spaced-apart relationship to the inner gasket cord, the outer gasket cord structurally distinct from the inner gasket cord, the inner gasket cord and the outer gasket cord of the manhole insert gasket each comprising a solidified, hardened, and cured gasket material comprising a synthetic silicone elastomer, the manhole insert gasket configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.   
     
     
         10 . The manhole insert of  claim 9  wherein each of the inner gasket cord and the outer gasket cord has a semicircular cross-section. 
     
     
         11 . The manhole insert of  claim 9  wherein each of the inner gasket cord and the outer gasket cord has a gasket thickness of 1.59 mm. 
     
     
         12 . The manhole insert of  claim 9  further comprising an annular inner gasket space between the manhole insert sidewall and the inner gasket cord and an annular middle gasket space between the inner gasket cord and the outer gasket cord, and wherein the middle gasket space has a middle gasket space width of 7 mm. 
     
     
         13 . The manhole insert of  claim 9  wherein the synthetic silicone eiastomer has a tensile strength of 335 psi and an elongation from 400% to 600%. 
     
     
         14 . The manhole insert of  claim 9  wherein the manhole insert gasket has a Shore Hardness of 25 and an Adhesion to Stainless Steel of 580 psi. 
     
     
         15 . A manhole insert having a manhole insert flange and suitable for deployment in a manhole opening of a manhole structure, the manhole insert fabricated by:
 inverting the manhole insert having the manhole insert flange;   forming a manhole insert gasket by dispensing a liquid gasket material onto the manhole insert flange along at least one circular dispensing path, the liquid gasket material including a synthetic silicone elastomer: and   solidifying and hardening the gasket material by curing the gasket material to form the manhole insert gasket with the cured gasket material, whereby the manhole insert gasket with the cured gasket material remains exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.   
     
     
         16 . The manhole insert of  claim 15  wherein the manhole insert gasket comprises an annular inner gasket cord and an annular outer gasket cord. 
     
     
         17 . The manhole insert of  claim 16  wherein each of the inner gasket cord and the outer gasket cord has a semicircular cross-section. 
     
     
         18 . The manhole insert of  claim 16  wherein each of the inner gasket cord and the outer gasket cord has a gasket thickness of 1.59 mm. 
     
     
         19 . The manhole insert of  claim 15  wherein the synthetic silicone elastomer has a tensile strength of 335 psi and an elongation from 400% to 600%. 
     
     
         20 . The manhole insert of  claim 15  wherein the manhole insert gasket has a Shore Hardness of 25 and an Adhesion to Stainless Steel of 580 psi.