242 Apparatus for preventing Pipes Bursting during Frost, 



liquid on a return of temperature. But in that case it is not so certain 

 that the piston would descend to its original position and open the cock. 

 Indeed, unless the combined friction of the piston and cock was very 

 small it would not. Besides, it being a primary object of the plan 

 to empty the pipes at the moment of shutting off the water, it would 

 be necessary in that case to employ two cocks — one for each purpose. 



To obviate this I have, therefore, thought it preferable to employ 

 a double-action valve of the description indicated in the diagram, 

 both as regards the relative simplicity of action in a valve to that of 

 a stop-cock, and, what is of greater importance, with the view of 

 effecting, at the same time, the shutting off of the water and the 

 emptying of the pipes. 



Explanation of the Plate {III') — Fig. 1 is a section ; fig. 2, an ele- 

 vation of the apparatus about one-fourth of full size. A represents the 

 junction of the ingress supply-pipe, which performs a curve into the 

 top of the double-action valve B. C is the supply-pipe continued on 

 its ascent to the cistern. D is the waste-pipe through which the pipes 

 are emptied. E is the small copper tube containing a measured 

 quantity of water ; it is supported by a small bracket attached to 

 the pipes. F is the piston accurately fitting into the copper tube, 

 and acting in direct conjunction with the valve in B. O is an air- 

 vessel. Now, if frost act on the small copper tube, the water it 

 contains is the first to freeze, expand, and elevate the piston, which 

 in its turn pushes up the valve from its present seat, and shuts it 

 with great force against the projected extremity of the ingress sup- 

 ply-pipe. A passage is thus opened between the ascending supply- 

 pipe C and the waste-pipe D, through Mdiich the whole water in the 

 pipes immediately escapes. By this means the water is shut off, 

 and the pipes emptied at the same time. By observing that the 

 valve shuts against the pressure of the water, it is evident that so 

 soon as the water again becomes fluid, it must exert that whole 

 pressure on the valve before it can escape, and it thus constitutes the 

 external pressure, if any were required, to depress the piston when 

 the temperature returns to its normal state. 



This construction of valve overcomes the only remaining difficulty 

 to the effective working of the apparatus. It should be attached to 

 the supply-pipe at the very lowest part of it. The place where the 

 pipe enters the house — often that of the cellar, area, or other low, 

 exposed situation — is the best. The water-pipes should possess a 

 downward inclination to this point — as, indeed, is generally the case 

 — for the purpose of being completely emptied. 



Mr Charles Baldwin, civil engineer, of Boston, United States, to 

 whom I am indebted for much valuable information on this subject, 

 suggests that an instrument of this kind might with advantage be 

 employed to indicate the sudden approach of frost. Other applica- 

 tions of a similar nature may very likely be made. Meantime, I 

 rest content with pointing out the existence of a principle which is 



