i>'2 ANNUAL OF SCIENTIFIC DISCOVERY. 



In an old invention of Timothy Clark, the valve is an elastic vessel, in. 

 closed in a cylindrical casing, on which is the fulcrum of the lever. Over 

 the elastic vessel is a cylindrical plate, with a projecting pin on top, that rests 

 against the lever one inch from the fulcrum. The lever is four feet long. 

 Thus, the motion of the end of the lever is forty-eight times that of the 

 valve. The elastic vessel is composed of a series of annular plates, soldered 

 to each other at their inner and outer edges ; they are made of brass, thin 

 enough to be elastic. This vessel is soldered on the end of a steam-pipe, 

 and no packing of joints is required. If the solder used is not too soft, this 

 valve may last for years without any attention. 



In a regulator, exhibited by TV. S. Gale, the valve is a circular disc of 

 India-rubber, protected by a similar disc of brass, which has been cut in 

 numerous strips, radiating from the centre, ana 1 is thus made yielding- 

 Such a valve cannot play much, and this deficiency is corrected by using 

 two levers, the one above the other ; the total increase of motion being 

 ninety. 



The valve of Patrick Clark, exhibited by the Patent Steam and Eire 

 Regulator Company, is also a disc of India-rubber, but not a flat one ; it has 

 the shape of a half sphere, Avith flanges around. A cylindrical envelop is 

 screwed over the rubber against a plate, but the lower portion of this casing 

 against which the rubber rests, has, like it, a spherical shape. A piston, 

 made convex underneath, is placed in the casing upon the India-rubber disc ; 

 this yielding to the weight, the centre portion turns inside, and becomes con- 

 cave, when the piston moves up and down by steam pressure. The bent in 

 the India-rubber has a kind of wave motion. By this arrangement a long 

 stroke is obtained. The pin between the lever and the piston is a separate 

 piece ; it rests on a deep recess in a projection cast on the piston. This pro- 

 jection slides in a box as a guide to insure the straight motion of the piston. 

 The effect of the lever is to increase the motion only fifteen times. This is 

 claimed as a great advantage by the exhibitor, for the reason that the bear- 

 ings of the valve in the smoke-pipe are rusty, and that to overcome their 

 friction the force corresponding to a short leverage is necessary. 



White's Valve is an elastic pipe, a foot long and three inches in diameter, 

 which is placed horizontally in a semi-circular trough ; over it is a long 

 square plate, flat at top and convex imderneath. The centre of this plate is 

 cast as a bearing for a rod, with a knife-edge, which acts against the lever. 

 The clastic pipe is made of several layers of hemp fabric, made steam-tight 

 with India-rubber. It is closed at each end by means of plugs. The fabric 

 and plugs are pressed together in the boxes of pillow blocks placed at each 

 end. One of these blocks is fast on the bed-plate, and the steam enters 

 through the plug in it. The other block is free to move to and fro as the 

 pipe becomes longer or shorter, by being more or less full of steam. The 

 leverage is one to twenty-four. 



Tho consumption of fuel in a boiler provided with a regulator is ten per 

 cent, less than when without it. This instrument is also a protection against 

 explosion, as when the pressure of steam rises it dampens the fire and thus 

 prevents the pressure from rising higher. 



