366 Descr'iption of an improved Pump. 



ger of being injured by the explosion, as is the case in the 

 common punjp ; in which this danger can only be avoided 

 by movnig the pump foot to one side of the pit, which ne- 

 cessarily throu's the whole column of pumps out of the 

 perpendicular. 



The construction of the clack is explained by figs. 3 and 

 4, the former being a section; and the latter a plan ; LL is 

 a cast-iron ring, fitting into a conical seat in the bottom of 

 the chamber of the pump, as shown in fig. 2 ; it has two 

 stems // rising from it, to support a second iron ring MM ; 

 just beneath this, a bar m extends across from one stem to 

 another, and has two screws tapped through it ; these press 

 down a second cross-bar /?, wbich presses the leather of ihe 

 valves down upon the cross-bar of the ring L, and this holds 

 it l^ast, forming the hinge on which the double valves open, 

 without the necessity of making any holes through the 

 leather as in common j but the chief advantage is, that by 

 this means the clack can be repaired, and a new leather put- 

 in in far less time than at present, an object of the greatest 

 importance ; for, in iDany situations, the water gathers so 

 fast in the pit, that if the clack fails and cannot be quickly 

 repaired, the water rises above the clack- door, so as lo pre- 

 vent any access to it, and there is no remedy in the conmion 

 pump but drawing up the whole pile of pumps, which is a 

 most tedious and expensive operation. In Mr. Brunton's 

 pun)p, the clack can at any time be drawn out of the pun)p, 

 by first drawing out the bucket, and letting down an iron 

 prong, fig. 3, which has hooks on the outsides of its two 

 poinrs ; this when dropped down will fall inlp the ring M, 

 and its prongs springing out, will catch the underside and 

 hold it fast enough to draw it u|). Another part of Mr. 

 Brunton's improvement consists in the addition of a pipe 

 H, fig. 2, which is cast at the same time with the barrel, 

 and communicates with it both at the top and at the bot- 

 tom, just above the clack; at the upper end the pipe is co- 

 vered by a flat sliding plate, which can be moved by a small 

 rod b, passing through a collar of leather; the rod has a 

 communiqation by a lever, so that the valve can be opened 

 or shut, by the men in the bottom of the pit ; the object 

 of this side pipe is, to let down such a proportion of the 

 water which the pump draws, as will prevent the pumj) 

 drawing air; though of course the motion of the engine 

 will be so adapted, as not to require a j^reat proportion of 

 the water to be thus returned through the side pipe; yet it 

 will not be possible to work the engine so correctly, as not 

 lo drav/ some air without this contrivance 3 and if it does, 



it 



