US1652921A

US1652921A - Mercury-vapor rectifier

Info

Publication number: US1652921A
Application number: US119683A
Authority: US
Inventors: Wimberger Leopold
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-08-26
Filing date: 1926-06-30
Publication date: 1927-12-13
Anticipated expiration: 1944-12-13

Description

Dec. 413, 1927.

L. WIMBERGER MERCURY VAPOR RECTIFIER Filed June 1926 Patented Dec. 13, 1927.

UNITED STATES LEOPOLD wmnnnenn, or VIEN A, Austrian.

MERCURY-VAPOR RECTIFIERv Application filed June 30, 1926, Serial No. 119,683, and in Austria August 26, 1925.

My invention relates to mercury vapor rectifiers for converting alternating current into direct current. In such rectifiers a special starting device forstriking the arc is necessary. It has been already proposed to use for this purpose a heating filament which, when heated, causes vapor of mercury to be evolved whereby the are is struck and the rectifier is started without tilting the rectifier bodily and without the use of a movable auxiliary electrode.

In the rectifiers proposed the heating filament, however, dipped freely into the mercury and therefore was liable to move irregularly, for instance in the case of portable rectifiers or rectifiers used on vehicles whereby the reliability of the rectifier is greatly impaired.

One of the objects of my invention is to avoid this inconvenience and to provide a compact reliable rectifier of the class above referred to.

Up to now for the manufacture of glass rectifier vessels or bulbs special sorts of glass had to be used which were not only expensive but also required particular care and skill in blowing.

It is one of the objects of my invention to provide means whereby cheaper sorts of glass, much easier to blow may be utilized in the manufacture of the glass bulbs of rectifiers.

With these objects in view my invention firstly consists in that both ends of the heating filament are secured to supply wires, the filament or one ofthe supply wires passing through the mercury and conducting the alternating current to be rectified to the mercury cathode. Furthermore my invention consists in an improved construction of the anode whereby the reliability of the rectifier in operation is greatly increased. The

- anode is constructed according to my invention as a metal cylinder located above the surface of the mercury; this anode therefore acts so to speak as a chimney in which con tinuously rise the mercury Vapors evolved, these vapors being subsequently condensed on the walls of the bulb.

Finally my invention consists in that I add to the mercury a small proportion of thorium oxide.

In the annexed drawing I have illustrated by way of example a rectifier constructed in accordance with the present invention.

4 caused to Fig. 1 is a circuit fier,

Fig. 2 is a sectional elevation ofthe rectifier used for charging the secondary battery. v

Through the primary winding of a transformer 1 alternating current 1s. caused to flow. The mercury cathode 2 of the rectifier 3 is connected by a wire-4 to the terminal 5 of the secondary winding of the transformer 1. The anode 6 is connected to the terminal 7 by a line 15 which includes an ammeter 8, the battery 9 to be charged and an adjustable resistance 10. A heating filament 11 serves for heating the mercury, part of such filament dipping into the mercury. Current is-sup'plied to the heating filament by the wires 4 and 12 and a switch 13 from taps ofv the transformer. The anode consists of a metal cylinder, preferably of iron, located vertically above the mercury surface and diagram of the rectifunncl shaped at its bottom end.

For starting the rectifier the switch 13 is closed. A current flows through the heating filament 11 heating the latter and thereby also the mercury so that mercury vapors are evolved. When the latter come into contact with the anode 6 connected to the other terminal of the secondary the arc is struck whereby the rectifier is started. The switch 13 is then opened which might be brought about automatically by an electromagnet not shown which is energized by the current flowing in the line 15.

The mercury vapors rise in the metal cylinder and are condensed on the cool walls of the bulb 16. and return in the form of drops into the cathode.

Fig. 2 is a sectional elevation of the rectifier, the wire 4 passes through a quartz tube 18. The second supply wire to the heating filament passes through the cylinder 14 enclosing a quartz tube 19 which ends slightly above the bottom end of the cylinder. The anode is held in position by a support 20 serving at the same time as a supply wire for the same and also holds in position the wire 4;.

In case the rectifier is designed for higher loads the switch 13 is not opened after the rectifier has been started, but current is permanently flow through the heating filament in order to avoid any dangerous cooling of the mercury, in case of large changes of the current intensity.

A particular advantage of the rectifiers constructed according to the present invention consists in that they may be manufactured similarly as ordinary incandescent lamps and therefore may be readily mounted in position and exchanged if necessary.

I have discovered that a rectifier operates under much more favorable conditions if mercury is used which contains an addition of thorium oxide. The proportion of thorium oxide is about three parts by weight of thorium oxide to one hundred thousand parts by weight of mercury. By this addition the are becomes much more steady and Q has a notably lower temperature; the pressure of the mercury vapor is lower and nevertheless its conductivity in one direction is greater. This permits as above stated to use for the manufacture of the glass vessels or bulbs of the rectifiers sorts of glass which are less expensive and more readily blown than'the sorts of glass which it was necessary to use heretofore for such bulbs.

While in the usual rectifiers a high vacuum i had to be maintained, in the resent rectifier a much lower vacuum will e found sulficient. Owing to the steadiness of the arc,

throttle coils and equalizing coils may be dispensed with. The best result-s are obtained by using mercury with an addition of thorium oxide in the rectifier hereinbefore described in which for starting the rectifier a heating filament is used. By using mercury with an addition of thorium oxide the costs of manufacture of the above rectifier may be greatly reduced.

hat I claim is:

1. In a rectifier'the combination of a bulb, a rigid metal anode, a mercury. cathode, a heating filament, a supply wire for each of the ends of the heating filament, both supply wires being sealed into the part of the bulb opposite to the mercury cathode, the supply wires passing downwards through the bulb and at least one of them dipping into the mercury.

2. In a rectifier the combination of a bulb, a rigid metal anode comprising a vertical hollow cylinder open at both ends, a mercury cathode, the said anode being arranged vertically above the surface of the said mercury cathode, a heating filament, a supply wire for each of the ends of the said heating filament, at least part of one of the said supply wires and a piece of the filament connected thereto passing through the said mercury cathode.

3. In a rectifier the combination of a bulb, a rigid metal anode, comprising a vertical hollow cylinder open at both ends having its bottom end conieally enlarged, a mercury cathode, the said anode being arranged vertically above the surface of the said mercury cathode, a heating filament, a supply wire for each of the endsof the said heating filament, at least part of one of the said supply wires and a piece of-the filament connected thereto passing through the said mercury cathode.

4. In a rectifier the combination of a bulb,

a rigid metal anode, comprising a vertical hollow cylinder open at both ends having its bottom end conically enlarged, a mercury cathode, the said anode being arranged vertically above the surface of the said mercury cathode, a heating filament, a supply wire 5. In a rectifier the combination of a bulb,

a rigid metal anode, comprising a vertical hollow cylinder open at both ends having its bottom end conically enlarged, a mercury cathode, the said anode being arranged vertically above the surface of the said mercury cathode, a heating filament, a supply wire for each of the ends of the said heating filament, at least part of one of the said supply wires and a piece of the filament connected thereto passing through the said mercury cathode, the heating filament pass ing axially through the said vertical hollow cylinder, and a quartztube being provided within such cylinder, the bottom end of the said quartz tube being above the bottom end of the said cylinder, a conductive support for the said vertical cylinder directly connected to one of the said supply wires, such support comprising an insulating holder located outside the said vertical tube and adapted to support the other supply wire.

6. In a rectifier the combination of a rigid metal anode and a cathode consisting of mercury with a small quantity of thorium oxide suspended in such mercury.

7. In a rectifier the combination of a rigid metal anode and a cathode consisting of mercury with an addition of about three hundred thousandth parts of thorium oxide.

LEOPOLD WIMBERGER.