US772519A - Boiler-furnace draft-governor. - Google Patents

Description

UNITED STATES Patented October 18, 1904.

,PATENT OFFICE..

BOILER-FURNACE DRAFT-GOVERNOR.

SPECIFICATION forming part of LettersiPatent N o..772,519, dated October 18, 1904,

Application filed April Z0, 1903.

To @Mu/hom 711 may concern.-

Be it known that I, FDMUND B. KIRBY, a citizen of the United States, residing atRossl'and, in the Province of British Columbia and Dominion of Canada, yhave invented acertain new and useful Improvement in Boiler-Furnace Draft-Governors, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

The invention relates to improvements in fluid-pressure regulators adapted especially for controlling the position of the draft appliances of a steam-boiler furnace.

, The object of the invention is to provide such a device in aform wherein a spring shall offer increasing resistance to the movement of the parts after the vdesired minimum pressure `of steam in the boiler has been reached, but in which it is not necessary to use a spring large enough to oppose the movements of the parts before such minimum pressure has been reached. In other words, the object of the invention is to provide a device wherein the increased resistance of a small spring may be l utilized instead of an excessively heavy and long spring.

In the drawings, Figure 1 is a side elevation, partly in section, of the best-known embodiment ofthe invention; and Fig. 2 is a sectional plan on the line 2 2.

Referring to the parts by letters, A repre# sents a support, to the lower end of which a'pot-cylinder B is secured, said cylinder being connected at its lower end with the steamspace of a boiler by means of a tube Z).

C is the piston, which is movable with as little friction as possible in said cylinder.'

D is the piston-rod, which is seated in a socket in the piston, from which it extends upward through asuitable guide-lug a on the upper end of said support.

E represent a compression helical spring which surrounds the piston-rod and lies bei tween said lug a and a collar d, which is ad? justably secured to the rod Dbelow this lug. Until the rod is forced upward by the piston this spring is not subjected to much, if any, pressure tending to compress it. y,

Two shafts F and G are mounted on the support A. Small sheaves f and g are secured -upon these large sheaves.

Serial No. 153,564. (No model.)

to these shafts, respectively, and ropes or cords wound thereon are attached to a yoke cl2, which is in 'turn secured to the piston-rod. Two large sheaves f g are also attached to theseshafts, respectively, and a weight or weights K are suspend ed from cords 7c, wound It will be seen that ifl the piston-rod moves upward it can only do so by raising these weights and winding their cords upon the large sheaves. These weights are of such size and the leverage produced by the difference in the sizes of the sheaves ff' g g' is such that these weights substantially balance the mechanism against the minimum pressure desired in the boiler. For example, if one desires to maintain in the boiler a pressure which shall vary between one hundred and one hundred and three pounds these weights and the described parts may be arranged to balance one hundred pounds. The spring E will thereafter oppose the movement of the piston and rod caused by the increaseof the steam-pressure.

It is obvious that a great variety of specific constructions may be made embodying the generic construction hereinabove describednamely, a construction wherein weights are employed which are capable of balancing the minimum pressure desired and a spring to resist the movementlinduced by a pressure in excess of the minimum pressure.

Having describedl my invention, I claim- 1. In a iiuidepressure regulator, the combination with a cylinder, of a piston, a rod secured thereto, a shaft rotatably mounted upon said cylinder, a sheave keyed to said shaft, a rope provided with a weight and passing around said sheave, a smaller winding-drum also keyed to said shaft, an arm secured to said rod, a rope secured tosaid armand passing around said small drum, connections between said rod and the draft-damper, and a spring for resisting the pressure under said piston after the resistance caused by said weight is overcome, substantially as described.

2. Ina fluid-pressure regulator, the combination with a cylinder, of a piston, a rod secured thereto, a shaft rotatably mounted upon said cylinder, a sheave keyed to said shaft, a rope provided with a weight and passing IOO around said sheave, a smaller Winding-drum also keyed to said shaft, an arm secured to said rod, a rope secured to said arm and passing around said small drum, connections between said rod and the draft-damper, a spring for resisting the pressure under said piston after the resistance caused by said weight is overcome, and means for adjusting the tension of said spring, su hstantially as described.

3. In a luid-pressure regulator, the combination With a cylinder, of a piston, a rod secured thereto, a shaft rotatably mounted upon said cylinder, a sheave keyed to said shaft, a rope provided with a weight and passing around said sheave, a smaller Winding-drum also keyed tosaid shaft, an arm secured to said rod, a rope secured to said arm and passing around said small drum, connections lietwcen said rod and the draft-damper, a nut threaded onto said rod and a spring between said nut and a stationary portion of the device for resisting the pressure on said piston after the resistance caused by said eight thereon has been overcome, substantially as described.

In testimony wher-col I hereunto allix my signature in the presence oi two witnesses.

ICDNIUND B. KlllY.

Titnessesz C. V. JENKINS, H. J. DARBY.

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