| 摘要 |
<p>PCT No. PCT/SE88/00133 Sec. 371 Date Sep. 6, 1989 Sec. 102(e) Date Sep. 6, 1989 PCT Filed Mar. 16, 1988 PCT Pub. No. WO88/07109 PCT Pub. Date Sep. 22, 1988.According to a method of preventing freezing in water piping there is arranged a non-return valve (3) upstream of the portion (1A) of the piping (1) which is to be protected, and a safety valve (4) downstream of this portion. The safety valve opens to allow the water to flow out and prevent freezing at a pressure increase of the water entrapped downstream of the non-return valve, the pressure increase occurring when the temperature falls from +4 DEG C. towards the freezing point. The invention also relates to a piping system for carrying out the method.</p> |
