Thawing bell and two hundred and twenty volt heating coil combination for unfreezing e.g. frozen manhole covering lying in ex-hazardous area, has bell and coil including diameters adapted to size and shape of valve, cap and covering

摘要

The combination has a thermostat adjustment knob for heat regulation formed at a handle. A thawing bell (1) is formed from steel or stainless steel in a semi-circular, angular or rectangular shape. A two hundred and twenty volt heating coil (2) is provided in the bell. Diameters of the bell and the coil are adapted to size and circular, angular or rectangular shape of a valve, a hydrant cap and a manhole covering according to DN 600-800standard. The knob is used for adjusting temperature and for beginning unfreezing process.