US340928A - Pantelbymos - Google Patents

Description

P. WRADY.

(No Model() AIR PUMP.

UNITED STATES PANTELEYMON VRADY, Oli"` ST. PETERSBURG, RUSSIA.

PATENT OFFICE.

AIR-PUMP.

SPECIFICATION forming part of Letters Patent No. 340,928, dated April 27,1886.

Application filed September 24, 1885. Serial No. 178,008. (No model.)

To @ZZ whom it may concern:

Be it known that I, PANTELEYMON WRADY, a subject of the Czar of Russia, and residing at St. Petersburg, Russia, have invented certain Improvements in Vacuum- Pumps, of which the following is a specification.

My improved vacuum-pump is more especially designed for exhausting the air from glass bulbs ofincandescent electric lamps, although it may be applied to other uses where a vacnum is to be produced.

In the accompanying drawings, Figure l is a vertical section of my improved pump, and

Figs. 2 and 3 are detached sectional views, drawn to an enlarged scale,of one of the valves.

The main portion of the pump consists of a cylinder or tube, a, about one hundred and twenty-tive centimeters long, with an inside diameter of 12.7 centimeters. The top of the cylinder a is closed by a cover, b, through which pass the rods cof the piston D, and also the rod e, for manipulating the stop-cock hereinafter described. This covering b carries a support, f, for bearings for the axis of a pinion. g, gearing into a rack on the piston-rod c, the shaft of the pinion being provided with a suitable crank-handle, h. On the same support f are bearings for a guide-roller, j, to support the back of the piston-rod c. The lower end of the cylinder a is closed by a bottom piece, 7c, the interior surface of which within the cylinder is made concave and the face of the piston d is made correspondinglyrounded to accurately fit the concave bottom of the cylinder when the piston isin its lowest position, so that the volume of oil then contained inthe space cannot exceed two hundred cubic millimeters.

The piston is provided with a suitable number of packing-pieces of leather pressed between the bottom of the piston and its screwring i. Within the piston is a cavity, Z, into which oil may be poured.

The pistou-rod c may be screwed or otherwise secured to the piston d, and through the center of the rod is avery fine conduit, at the upper end of which is a stop-cock, r. As illustrated more fully in Figs. 2 and 3, the plug s of this valve has two passages at right angles to each other, and a side opening is'formed in the pistonrod, so that when the plug s of the valve is turned to the position illustrated in Fig. 2 this tine conduit in the piston-rod will be open to the interior of the cylinder a. Through the bottom piece, k, is bored a central conduit closed by a stop-cock, m, and opening at its lower end into a small reservoir, n, for collecting the drops of oil. This reservoir n is provided with a bent tube, o, to which is attached a glass tube, p, having a communication with the globe from which the air is to be exhausted. This glass tube phas a side opening closed by a small indiauubber reservoir, q, filled with oil, and provided with an internal spiral spring, by which it may be kept distended, and in the tube pis formed an enlargement, p', the object of this iexible reservoirp and its enlargementp being,as hereinafter described, to serve as an indicator of degree to which the lamp has been exhausted.

The operation of the apparatus is as follows: The stop-cocks m and r being closed, and the piston d being at the bottom of the cylinder a, and the lamp to be exhausted being tightly connected with the end of the tubep, the piston d is rst caused to ascend by the turning of the crank h, and when it has arrived at the end of its stroke the stopcock m is opened. The air in the lamp-globe and piping is thus rareed by being drawn into the exhaustcylinder a. The stopcock m is then closed, and the cool; ropened by means of the rod e, which is connected byacrank to the plug of the cock, as illustrated in Figs. Zand 3. rIhe piston d is then caused to descend until it reaches the bottom of its movement, so that the air below the piston in the cylinder c will passthrough the conduit in the rod c of the pump-piston as the latter descends. When the piston reaches the bottom of its movement-,the coclm' is closed again and the piston raised, and when the latter reaches the top of the cylinder the cock m is then opened again, so that a further rarefaction of the air in the lampglobe is produced, and the operation is repeated unt-il the desired vacuum is obtained. A few pistonstrokes inthe pump of the dimensions described are sufticient to produce a vacuum of about one seven-millionth of the atmospherical pressure.

In order to know when the desired vacuum has been obtained, I make use of the indicating devices above referred to and consisting oi the oil-reservoir q and pipe p, with its en- IOC largement p', the operation being` that when the cock m is opened and the air in the tubing therefore suddenly drawn into the cylinder a, a drop of oil will be projected from the top of Jthe reservoir q into the enlargement p of the glass tube p, and this Will be repeated until the amount of air in the tubing,` is so small as to have no visible effect on the oil When the cock m is suddenly opened. In order that the action of an insignificant quan tity of air still remaining` in the lamp-globe may nevertheless show its effect on the oil7 I diminishthc volume of oildrop moving in the glass tube p by stretching the india-rubber res ervoir q by hand, thereby increasing,` the ca pacity of the reservoir.

It Will be understood that by making the cylinder a longer a still greater rarefaction of air'may be obtained, and this degree of rare faction may be still further increased by heating thelamp-globe while thepunip is in action.

I claim as my invention- 1. The hercin-described vacuum-pump7 consisting of a cylinder having a cock at its lower end and a piston provided with a fine conduit and cock therein, as described.

2. The combination of an exhaust-purnp with a vacuum-indicating device consisting of a tube communicating with the chamber to be exhausted, and having an oil-reservoir, substantially as specified.

3. The combination of the cylinder a of a'

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