Metal winding mat characteristics
The metal wound mat accurately utilizes the heat resistance, resilience and strength of the metal and the softness of the non-metallic material, so that the sealing performance is better, and the performance of winding the flexible graphite mat with the stainless steel strip is optimal. The pre-tightening pressure is smaller than that of the asbestos winding mat, and there is no disadvantage of leakage of capillary pores of asbestos fibers.
In oil media, metal strips use 0Cr13, while other media recommend 1Cr18Ni9Ti.
The stainless steel belt with flexible graphite winding mat is used in a gas medium with a pressure of 14.7 MPa (up to 19.6 MPa in the country) and 30 MPa in liquid. Temperature -190 ~ + 600 ° C (available to 1000 ° C in the absence of oxygen, low pressure).
Polytetrafluoroethylene wound mats can be used in low temperature media such as liquid hydrocarbons. At the same time, the resonance is enhanced by the addition of the metal strip, and the temperature of the PTFE winding mat can reach 250 ° C, and can be used in acidic medium to 9 MPa, 200 ° C.
For medium and above pressures, if the temperature exceeds 300 °C, the inner ring, outer ring or inner and outer rings should be considered. If a concave-convex flange is used, the winding mat with the inner ring is better.
In a large-scale fertilizer plant, the waste heat boiler is a key equipment for high temperature and high pressure. It uses a flexible graphite winding mat with an outer ring, which does not leak at full load and leaks when the load is reduced. A flexible graphite plate with a thickness of 0.5 mm was added to both sides of the gasket, and it was cut into an arc shape, and the joint portion was overlapped by a slanting opening, and the use condition was good.