US226165A - Electric alarm for pressure gages - Google Patents

Description

G. D. EARLL. Electric Alarm for Pressure-Gages.

Patented April 6,1880.

N PETERS, PHOTO LITHUGRAPHER, WASHINGTON, D c.

UNITED STATES GEORGE D. EARLL, OF NEW YORK, N. Y.

ELECTRIC ALARM F OR PRESSURE-GAGES.

SPECIFICATION forming part of Letters Patent No. 226,165, dated April 6, 1880.

Application filed November 28, 1879.

To all whom it may concern:

Be it known that I, GEORGE D. EARLL, of the city and county and State of New York, have invented a new and Improved Electric Alarm or Device for Use upon Steam-Pressure Gages, of which the followingis a description, reference being had to the accompanying drawings, and to the letters of reference thereon, making a part of this specification.

Electric alarms have been heretofore used in connection with steam pressure gages, but they have been so made as to be a part of the gage itself, and have required a particular or special construction of some part of the gage, or they have been so constructed as to interfere more or less with the continuous and free action of the gage as a pressureindicator.

My improved alarm device can be attached to any steam or pressure gage in use, and without requiring any alteration in its parts, and does not, in any degree; interfere with the freest action of the gage as a pressure-indicator under any and all pressures. It is also simple in arrangement, cheap in construction, and certain and automatic in operation.

Figure 1 shows a pressure-gage with my electric-alarm device attached. Fig. 2 is a detached view of the circuitclosing device which is attached to the gage. Fig. 3 is asectional view of Fig. 2 through the line a m. Fig. 4 is a detached view of one end of the index-hand by which the circuit is closed.

A represents the dial of an ordinary pressure-gage, placed within a case or shell, B, and upon which moves the index-hand C. To the shell or case or dial of the gage, and connected therewith by screws 1 1, I attach the part D, Fig. 2, which consists of a metal plate or rim, to, to which is fixed an insulated block or plate, Z), most conveniently and cheaply made of hard rubber, which extends over the outer edge of the dial, and to the inner side or edge of which is connected a metal face-plate, 0, which is so connected therewith, as seen in Fi 3, that it will not be in contact with any part of the gage.

Connectin g with the metal plate a, as shown in Fig. 2, or directly with the shell or case of the gage, is an insulated wire, 2, and another similar wire, 2, passes into and through the insulated block or plate I), and connects with its metallic face-plate c. The other ends of such wires connect with a suitable battery and alarm.

The plate 0 being insulated from the gage, the electric circuit between the gage and bat tery and the alarm is open under ordinary circumstances, and at such time or in such case no alarm is given; but whenever contact or electrical connection is made between the gage and the plate 0 the circuit will be closed and an alarm made. This contact is effected by means of or through the common index-hand O, which indicates the pressure existing at any time when the pressure is sufficient to bring the arm or end 3 of the index-hand upon the plate 0, the part D being placed on the gage in such location that the end 3 of the index-hand will not come in contact with the plate 0 until the pressure has become such that danger may be apprehended or special notice is desired.

Fig. 1 shows the index-hand in two positions, the heavy lines representing it in a position when the circuit is open and no alarm produced, and the dottedlines showing it when in contact with plate 0, at which time the circuit is closed and the alarm made or attention called.

To insure a continued, free, and proper action of the gage as a pressure-indicator, it is necessary that the contact between theindexhand and the plate 0 should be effected or the circuit closed in such a manner as not to interfere in any manner with the free and continuous movement of the index-hand and the natu *al action and operation of the gage. This I accomplish by so constructing and arranging the parts that theindex-hand will not strike or press against the metal plate 0, and thus in any degree obstruct the free movement of the hand or affect the natural action of the gage, but will slide upon or pass over such parts, and with the least possible friction or resistance.

To produce the least friction between the hand 3 and the plate cas the former slides upon or passes over the latter, I place upon the end of the hand a loosely-revolving wheel, 3, the hand 0 being also so supported 011 its standard that the periphery of the friction-wheel 3 will be only a very little below the horizontal plane of the plate 0.

With such a construction and arrangement of the parts by which the circuit is closed the gage will act as free] y and perfectly as a press lire-indicator asif the alarm werenotconnected with it, and Wlll continue so to act after the alarm has been given, and the hand can freely pass beyond the platec if pressure is increased.

The arrangement of the plate 0, as before de scribed, also renders it possible to secure acon tinuous alarm during any desired length of time or during any desired number of degrees.

My improved electric-alarm device, as will be evident from the foregoing description, can be attached to and combined with any pressure-gage without any change in its construction, and will not in any manner interfere with its ready action as a pressure-indicator, and is simple in construction and automatic in operation.

What is claimed as new is The circuit-closing device D, consisting, substantially, of rim a, insulated block b, and plate 0, in combination with the indcxhaud and dial of a pressure-gage, the index-hand and device D being connected by properly-insulated wires with a suitable battery and alarm, for the purposes set forth.

GEORGE D. EARLL.

Witnesses:

S. NuLsoN WHITE, SAMUEL LEA.

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