US419967A - Steam-boiler water-level indicator - Google Patents

Description

(No Model.)

J. MoDONALD. STEAM BOILER WATER LEVEL INDICATOR. v

No. 419,967. Patented'Jan.21, 1890.

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UNITED STATES PATENT OFFICE.

JOHN MCDONALD, OF PITTSBURG, PENNSYLVANIA.

STEAM-BOILER WATER-LEVEL INDICATOR.

SPECIFICATION forming part of Letters Patent No. 419,967, dated January 21, 1890.

Application filed July 28, 1888. seanmzanssa (no model) To all whom it may concern.-

Be it known that I, JOHN MCDONALD, of the city of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Steam-Boiler Indicators; and I do hereby declare the following to be a full, clear, and exstructed with alarms-either a whistle, the

valve of which is operated by a float in the boiler, or an electrical a1arm-bell, the circuit of which is controlled by a similar float. Such devices are, however, objectionable, because they tend to cause the engineer to rely too much on the working of the apparatus and to become careless in his attention to the boiler, and if forany reason the apparatus should get out of ordgr the safety of the boiler might be endangerec.

To obviate this objection I have devised the present invention, which consists in an apparatus which is so constructed as to mark and keep an accurate record of the quantity of water in the boiler at all times, the purpose being to give to the employer means of observing what the water-level has been at any time, and thus enabling him to detect any lack of attention on the part of the engineer, such apparatus including an automatic signal which shall indicate any dangerous elevation or fall of the water.

Referring now to the drawing, 2 represents the steam-boiler.

3 is a float in the boiler, having a projecting arm 4, which is fixed to a short rotary shaft 5. This shaft passes through a stuffing-box 6 in the boiler-head, and has fixed to it on the outside of the boiler a pointer or indicating-finger 7. When thus constructed, it is evident that any rise or fall of the float, owing to variation in the waterdevel, will aifect a radial motion of the pointer 7, either to the right or to the left, accordingly as the water rises or falls.

8 is a dial plate or card, which is set in a suitable case 9, and is moved therein, preferably in a rotary direction, as indicated by the arrow, by means of suitable clock-work, so that as it rotates its face shall be in contact with a pencil or stylus 10 at the end of the pointer 7. As the card rotates, the pencil will produce a mark thereon, which, if the waterlevel be constant, will be exactly circular; but if the float is moved 'by variation of the water-level the pencil will be moved to the right or left, and the mark on the card will be correspondingly irregular. It follows, therefore, that if the instant of time when any given point on the card passes the stylus be known the position of the mark at that point will indicate what the water-level is at that time, it being known, of course, what point on the dial will be marked at the mean waterlevel. To this end I divide the card radially into divisions representingdivisions of time. In the drawing I show it divided into seven principal parts, representing the days of the week, and having subdivisions indicating the hours of each day, The lines indicating these divisions should correspond to the motion of the pointer, and in the arrangement which I show in the drawing should be made on arcs of a circle described on a center coincident with the axis of the pointer and whose radius is the distance from the axis of the pointer 7 to the stylus. The card may of course be divided by a greater or less number of marks to indicate, for example, the boiler variations for two weeks, for a day, or for any other pe .riod of time, and the clock-work which drives the card should be timed to impart to it one complete revolution in the period during which the card is designed to record. The card is inclosed in a case, preferably with a glass cover, and the case may be locked, so as to prevent tampering with the instrument. It affords at all times an accurate record of the condition of the water-level, either at the present moment or at a previous time, which is apparent on glancing at the card, and if the engineer carelessly allows the water'to fall too low he does so at the risk of detection. of his carelessness by his official superiors. Thus the card shown in the drawing indicates that from twelve oclock on Mondaymorning until four oclock on Friday morning the water-level was substantially the same, with only slight fluctuations above or below the normal level, and that at the time last named the water-level suddenly fell, and that it remained at a low level until six oclock, when it rose again to the normal level and continued so until Friday noon. lVhen the markon the card has traversed the entire circle, the card may be removed and either preserved as a record or thrown away, and a fresh card is substituted for it. I use an electro-magnetic bell 12, and in the circuit of its conductors place a battery 13. The end of one conductor is electrically connected with the pointer 7, and the other conductor is connected with a metallic contact ring or plate 1%, which is fixed to the case near the center of motion of the dial, and is also connected with a second metallic contact ring or plate 15, which is fixed to the case at or near the rim of the dial. The pointer is made of metal, and if the water-level should change in either direction sufficiently to reach the danger limit the consequent unusual motion of the pointer to the right or left would bring it into contact with either the plate 14: or 15, in either case completing the circuit through the battery and bell-magnet and causing the bell to ring.

The apparatus which I have described and shown is one of great utility and merit, and its numerous advantages will be appreciated by those skilled in the art.

The apparatus may be varied greatly in form, size, and details of construction by me chanical changes such as will suggest themselves to the skilled mechanic, and I do not in the broad claims of this patent intend to limit my invention to the precise arrangement and construction which I have shown and described; but

What I claim is- A recording water-indicator for stcan1-boilers, comprising a pointer, a rotatable card having a metallic center plate 14 and a metallic rim-plate 15, with which the pointer may come into contact, an electric circuit including said plates and the pointer, and an alarm, substantially as and for the purpose described.

In testimony whereof I have hereunto set my hand this 25th day of July, A. D. 1888.

. JOHN MCDONALD.

Witnesses:

W. B. Conwm, THOMAS W. BAKEWELL.

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