US2303121A - Illuminated manometer - Google Patents

Description

Nav. 2,4, 1942. y v R HATNESS l 2,363,r21V

ILLUMINATED MANMET'ER Filed Nov. i7, 1941 ATTORN EYS Patented Nov. 24, 1942 'UNITED' STATES PATENT -OFFICE C.

Application November 17, 1941, Serial No. '419,511

(Cl. 24o-2) 3 Claims.

This invention relates to manometers, particularly to the type employed for ascertaining blood pressure in which a mercury column or equivalent uid body is pressure responsive to constitute the indicating element of the instrument, and has among its objects and advantages the provision of novel illumination for such a device to render the pressure reading easier, to facilitate reading in the country and homes where lighting conditions are not the best, and in sick rooms where strong lights are not desirable. 'Ihe instrument is designed with a view to simplicity and durability, and a small battery is electrically connected into the instrument as a source of current supply, with an electric lamp interposed in the electric circuit and associated with the mercury containing tube in a novel manner to eiectively illuminate the latter to facilitate reading of the scale.

In the accompanying drawing:

Figure 1 is an elevational view of a manometer in accordance with my invention, with certain parts broken away for the purpose of illustration;

Figure 2 is a top plan view; and Figure 3 is a sectional detail view illustrating the manner in which the electric lamp is associated with the mercury tube.

In the embodiment. selected to illustrate the invention, the glass tube I0 is provided with the usual scale I2 etched in the glass, and the lower end of the tube is secured in a socket I4 formed on a fluid reservoir I6 which carries a supply of mercury I8. To the reservoir I6 is connected a tube for connection with the customary ination facilities for applying pressure to the mercury in the reservoir to force mercury up into the tube I 0. The structure so far described is old and well known in the art and need not be set forth in greater detail.

Referring to Fig. 3, a metallic sleeve 22 is lnserted on to the upper end of the glass tube Ill, and a cap 24 has its tubular part 26 pressed on to the sleeve 22, the tubular part 26 being slotted at 28 and fashioned so as to resiliently press on to the sleeve. y

The threaded conducting sleeve 30 of the threevolt electric lamp |32 is threaded into the bore 34 in the cap 24, and the central terminal 36 of the lamp 32 engages a terminal 38 carried by a body 40 of insulating material. To the outer end of the terminal 38 is secured a wire 42 connected with one terminal of a three-volt battery 44, and the other terminal of the battery is cona terminal 48 secured to the metallic reservoir I 6.

One end of a wire 50 is electrically connected with the sleeve 22 and the other end is connected with a silverterminal 52 .extending through the wall of the glass tube to be engaged by mercury as it rises in the tube. Terminal 52 is preferably located at about the 25 mm. mark of the scale. To facilitate handling ofthe instrument, a switch 54 is interposed in the wire 46 so as to positively break the circuit, as when the instrument is being carried in its case or the like.

When pressure is applied, as through the medium of the usual arm band, the mercury rises in the tube. When it reaches the 25 mm. mark, the mercury makes contact with the terminal 52, which completes the circuit and the light is turned on. The light shines down the tube Ill and on the mercury therein. The mercury in turn reflects the light thus making the manometer easy to read. When the mercury recedes beyond the 25 mm. point, the circuit is broken and the light is turned oif.

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

I claim: Y

1. In a manometer, the combination of an upright transparent tube having a scale thereon, a relatively opaque conducting liquid pressure responsive to rise in the tube, an electric lamp located inside the tube to illuminate the tube and liquid surface, an electric circuit electrically connected with the lamp and said liquid, and a terminal interposed in said electric circuit extending inside the tube to be engaged by said liquid when elevated a predetermined distance in the vtube to close the circuit.

2. In a manometer, the combination of an upright transparent tube having a scale thereon, a relatively opaque conducting liquid pressure responsive to rise in the tube, an electric lamp located inside the tube to illuminate the tube and liquid surface, an electric circuit electrically connected with the lamp and isaid liquid, a terminal interposed in said electric circuit extending inside the tube to be engaged by said liquid when elevated a predetermined distance in the tube to close the circuit, and a switch interposed in said circuit to break the latter when said liquid is in contact with said terminal.

3. Ina manometer, the combination of an upright transparent tube having a scale thereon, a relatively opaque conducting liquid pressure renected with a wire 46 electrically connected with 55 sponslve to rise in the tube, a conductor sleeve secured to the upper end of said tube, a conductor cap detachably engaging said sleeve, an electric lamp inside the tube and having an outside terminal electrically connected with said cap, said lamp being provided with a central terminal, a terminal post supported on said cap but insulated therefrom and arranged to engage said central terminal, a battery, a connection between one terminal of the battery and said terminal post, a connection between the other terminal of the battery and said liquid, a terminal carried by said tube and extending therein above the normal level of the liquid, and a connection between said last terminal and said sleeve, said last terminal being engageable by said liquid when elevated a predetermined distance in the tube to close the circuit through said lamp.

WILLIAM R. HARTNESS.

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