US1153976A - Mercury-vapor apparatus. - Google Patents

Description

P. H. THOMAS.

MERCURY VAPOR APPARATUS.

APPLICATION FILED NOV. 1. I913.

1,153,976. PatentedSept. 21, 1915.

2 SHEETS-SHEH I.

WITNESSES INVENTOR AZUR/VEY P. H. THOMAS.

MERCURY VAPOR APPARATUS.

APPLICATION FILED NOV. 1. 1913.

1,153,976. PatentedSept/Ql, 1915.

2 SHEETSSHEE12.

63 61 lA/VE/VTUR 6 5 BY 57 T GAW' a/ I 47mm mart an snares rnrnur smea- PERCY H. THOMAS, 012* UPPER'MONTCLAIR, NEW JERSEY, ,ASSIGNOR T COOPER- HEWITT ELECTRIC 00.; OF HOIBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

Specification of Letters Patent.

MERCURY-VAPOR APPARATUS.

Patented'sept. 21, 1915.

Original application filed September 12, 1912, Serial No. 719,924. Divided and this application filed November 1,' 1913.

'1 0 all whom it may concern:

Be it 'known that I, PERCY H. THOMAS,

, a citizen of the United States, and resident of UpperMontclair, county of Essex, State of New Jersey, have invented certain new .and useful Improvements in Mercury-Vapor Apparatus, of which the following is a specification.

My invention relates to the operation, of mercury vapor lamps and especially to such lamps when operated at relatively high pressures, from sources supplying alternating current.

' My invention aims to provide means making it possible to operate such a lamp or other apparatus by passing current from the source in opposite directions between the same electrodes. When mercury vapor lamps are operated from alternating means at relatively low pressures it is usually more convenient to provide an extra anode and pass the current alternately-from the two anodes to the same cathode. However, by the method of operation hereset forth it,is possible to operate from analternating supply directly with only two electrodes.

' The mercury vapor lamp has a very high resistance to starting, but when the temperature of the elect odes, assuming these to be of-mercury, is raised sufficiently, this starting resistance is much lowered and a lamp that will not run on a certain voltage cold will operate satisfactorily on this voltage when its temperature is sufiiciently high. I overcome the difiicult'y of getting the lamp heated to the point at which it will operate on normal alternate voltage by various methods, such as raising the alternating voltage at the start, shortening the vapor path at the start, or preheating the mercury before attempting to start the flow of current in the vapor; I donot, however, claim to be the first topreheat the mercury of a vapor lamp broadly. The application of these arrangements will be pointed, out in more detail in connection with the various figures of the drawings.

It may be well to point out that the nor- 51113.1 resistanceto current flow in these mercury vapor dev ces depends as one factoru on the, pressure of the vapor which 1n iturn depends upon the temperature of the mercury inlthe container. The relation be- Serial No. 798,663.

tween the amount of heat generated-in the;

mercury by the operation and the natural rate of heat dissipation of heat from the. mercury is the factor determining the normal temperature of the mercury and the various parts and current strengths may be proportioned in conformity therewith.

It is furthermore well known that such apparatus operates most satisfactorily when there is some voltage absorbing device ini series therewith or when it is fed by.constant currents.

In the drawings, Figure 1 represents a mercury vapor lamp adapted to operate on alternating current and provided with means age during the starting period and a difier-- ent method of overcoming the initial opposition to the flow' of current.

Fig. 6 a modification of the starting circuits.-

Figs. 7 and 8. show two arrangements for obtaining additional starting voltage on constant potential circuits.

In Fig. 1, 1 represents the container of the lamp or other apparatus; 2' and 3 ele'ce' trodes of mercury or other materialyd rep Fig. 5 shows a second view of the lamp of Fig. 4;, and

resents the core of a transformer havinga' primary winding 6 and a secondary wind-"1 ing 5;? and 8 represent starting bands as used in many commercial mercury vapor lamps; 10 is a constant current alternatmg supply and 9 is a shunt cutout for shor circuiting the lamp when not in service. 11, 11 are constrictions in the passages containing the mercury which serve to check the oscillationsor rushes of mercury which tend sometimes to occur in practice. 'This" lamp is, preferably constructed and ex-;--

hausted as is usual for mercury vapor lamps, that is by exhausting all gases from the oontainer and the walls of the chamber. However, it will be found advantageous in some cases to facilitate the initial starting by leaving in a certain amount of residual gases between the electrodes. The presence of such gas serves to lessen considerably the,

resistance of the device to the initiation of current flow. The container is hermetically ,with current in the main circuit, a voltage is impressed on the primary 6 which in turn causes a potential to be impressed upon the secondary 5 and on the lamp terminals 2 and 3 and the starting bands 7 and 8.

The effect of these starting bands is well known; they produce small sparks on the inside of the container at the level of the mercury surface which acts to overcome the initial opposition at the electrode to the starting of current flow. The voltage of the secondary 5 is so chosen as to be considerably higher than the proper operating voltage of the lamp, when in its stable operating condition.-

This extra high voltage serves to greatly facilitate the starting of current flow in the first moments of start ing when the lamp is not very hot. When, however, the'pressure of the mercury vapor has been sufficiently raised by the operations so far described, current flows more freely and assumes its normal value, when the voltage of the secondary 5 drops to normal. As the temperature and pressure of the lamp rise, the mercury in the electrodes 2 and 3 will be forced" down until the chambers 22 and 23 are filled with mercury and then no further elongation of the vapor path can occur. The transformer core 4 can .if desired be made without the provision for magnetic leakage, since it is here taken as in a constant current circuit and the voltage will thus automatically be very high when no current is passing in the lamp and will automatically drop to the minimum value that is sutlicient to maintain the normal curheated up. It will be observed that the lamp and circuit is symmetrical and that when the supply potential is in one direction, one starting band is effective and starts the current flow in that direction and that when the supply potential is in the opposite direction, the other starting band then starts the current in the other direction. The current once established continues freely of course for the remainder of the alternation.

In Fig.2 is shown a somewhat similar set'of circuits except that in this figure two additional electrodes 2land 25 are provided in the lamp and when the pressure has risen in the vapor path the mercury electrodes will be pushed back until they reach-these additional electrodes and connect the main circuitdirectly to the electrodes. In this case while a portion of the current will continue to main portion will pass through these addifiow through the secondary 5,.,the.

tional electrodes, 24 and 25. In the lamp of this figure the chambers 12 and 13 are provided to give a certain flexibility to the operation of the lamp for as the pressure in the vapor path rises, the mercury will recede. from the center portion and rise in the outside portions and if a suitable amount of air be placed in the chambers 12 and 13 they will resist more and more,. vigorously until a very great increase in pressure in the central portion will be required to cause even a small increase in the compression in the chambers. This is often a desirable adjustment, as it tends to prevent one lamp from taking too much voltage I when run in a series since a very long vapor path might be produced were there no gas in the chambers 12 and 13. However, under other conditions the reverse condition may be more desirable. Except in the points already mentioned this system is the same as that of Fig. 1. In either figure the container may be made of any one of many substances, such as ordinary flint glass, German glass, Jena glass, Bohemian glass, quartz or any hard glass containing a large proportion of silica, especially where high temperatures are expected. It is of course necessary to use suitable leading-in wires for each particular container, for example, platinum for flint glass with the usual hermetical seal. A mercury sealed ground joint may, if desired, be employed where quartz is used.

F ig. 3 shows a different form of tube from that shown in Figs. 1 and 2. In the system of Fig. 3 the container 1 consists of an inverted U, and there is consequently no opportunity for the variation of the length of the vapor path. This tube is started by a high voltage obtained from the secondary 16 of the transformer primary 17 connected in shunt to the lamp. The secondary of this transformer is connected to the primary at its middle point so that there will be a high voltage on the particular supplementary electrode, 14 or 15, which is appropriate to start current flow to that particular main electrode 2 or 3 which may be for the moment acting as a cathode for the main cur- 1 rent. The relation of currents is shown for one direction bythe arrows. The voltage on the primary 17 will be very high since it. has the full current .of the main circuit to carry when the lamp is not started, giving a large magnetizing current, for the circuit 10 is taken as a constant current circuit. When, however, the lamp starts, the voltage on the primary 17 falls as the voltage on the ,lamp then falls and the waste of having the 125 transformer fully excited is avoided. The parts 21 are solid bodies, preferably nonconducting, as for example, hollow glass cylinders, introduced to reduce the section of the mercury column below the electrode sur- 130 face and prevent the conduction of heat to\ the seals when a high temperature lamp is used. They also prevent shocks of the mercury in moving the container. The resistance 20 and the inductance 19 are for regulating purposes.

' used as an electrode material for both elec- :tween the electrodes 2 and 3. :Qlhe rod trodes as. shown, there being a sufficient amount in the container for br dging bemarked 38 serves as a shaft or aitis about which the lamp is rotated in the starting position. The starting of lamps of the mercury vapor type for low pressure -or high pressure operation iswell understood. One advantage Which'is of'importance in the presenbcase is the fact that, when the electrodes are relatively cold, the current path in the vapor is relatively short, thus in effect providing excessive voltage to the short are, especiallyif the tilting motion be made sluggish and some measurabletime interval be given for heating the electrodes before the full vapor path is introduced into the circuit. The-circuit 58 in Fig. 4 isa constant current circuit, the in'tluctances27 and 29 and the resistances 28 and 30 being regulating and current remitting mains. T secure in a system as here shown, an added potential between the lampterminals upon the lampin the main circuit by means of the transformer 26, here-shown as an autotransformer, as will be understood from the drawing. In initial position, the revolving arm 33an'd the armature 36 attached thereto, iscarried' downward by the weight 37 until the contact 41 bears on the contact block 34.

- The path of the main current in the circuit 58' isthen through the second and third sections measuring from the left of the transformer-winding and the inductance 29 and the resistance 30, the contact 34, the lever 33 and the line wire 58 giving'relatively high yolt'age on the lamp. When, however, the device has been started,'the current fiow ing'therethrough will energize the coil 31 and raise the armature 36, the contact point 41 will then connect with the contact block and current will flow to only the central portions of the transformer 26 thus reducing the voltage on. the lamp. 3232 are devices similar to that just described located in the maincircuit 58.

Fig. 6 shows an alternative method of operating the contact point 41 of Fig. 4. At

' the startbefore the initial current flo\vthe energizing coil 39 attracts the armature 42for there is a relatively'high potential on $5 the'device whose electrodes are shown at 2 and 3. The resistance 'serves to. control the current through the coil 39 in shunt to the device. Before the weight 37 can move the contact point 41 from the contact block 35 to the contact block 34, below, the voltage in the lamp must be greatly reduced as when the relatively low operatingyoltage is impressed thereon. The transformer ratio is then lowered as-before. In Fig. 6 the potential on the lamp operates the shift mechanism while in Fig. 4 this mechanism is operated'by the current through the device.

Fig. 7 shows a system in which a mercury vapor lamp, more particularly a high pressure vapor lamp is operated from a constant potential source. The voltage is applied to the lam-p through a transformer here shown as a raising auto-transformer; it might equally well of course be made a lowering transformer. Voltage is fed from the circuit 57 to the transformer 47 through the contact block 52 in the starting'position,

and through a high potential for starting but into the block 53 during running conditions. This change of connection is accomplished by means of the contact point 51 which is jointly controlled by the spring and the coil 45, the latter. coil being included in the lamp circuit, and operating upon the armature 55 at one end of the lever 54, the latter turning on the pivot 56. Inductance devices 484848 and 46 as well as resistances 4949-49 and 44 serve a regulating function. These devices may be given any desired relative proportion, one to the other. The operation of this system is clear and is intended to cover the adaption of the prior apparatus for constant potential mains. The device 43 may have its reluctance to the current flow overcome by any of the methods shown in this application or known in the art, for example, by tiltingor by starting bands.

In Fig. 8, I show another system of cir-' cuits adapted for any of the mercury vapor devices so far described. When current is thrown on the constantjpotential mains 57 the transformer primary 58 is energized through the inductance device 62, the resistance 63, the conductor 66 and the cut-out contacts 64-65. This energizes the trans former 59, which in turn-produces the voltage in the secondary link lio, which may be given any desired ratio to the primary 58. \Vhen the lamp starts the coil 61 is energized by the flow of current which opens the cut-out -6465, thus interrupting the current in conductor 66. The current is then forced through the device 43 by waV of the primary 58 and the secondary of the transformer, whose core 59 is provided with a shunt leakage path having an open magnetic circuit. These two coils operating together, produce in effect an inductance de-. vice in series with the circuit which operates as steadying means. Where desired, a very high potential can thus be impressed upon the device 54 during the starting period only, without maintaining such high potential during operation.

While I have described my invention with regard to these specific diagrams and figures illustrated, I do not wish to limit myself to the particular embodiments of my invention but consider any system utilizing the novel features of this disclosure to come within my invention.

Any of the lamp structures shown may, if desired, be made of'quartz or any of the other material described for the device of Figs. 1 and 2, for these devices may be used over a wide range of pressure. Of course,

in each case the pressure of the vapor, the

dimensions of the tube, the voltage impressed and radiating power of the apparatus must be properly correlated to secure the results described.

Many of the lamps shown may be operated to advantage upon direct current, but in this application I have illustrated more particularly alternating current sources. Material other than mercury may be used in these tubes and when run at a high temperature any material, even material solid at the temperature appropriate to low pressure lamps may be used as the electrode material. I

may mention tin, which has a very low vapor pressure; zinc and copper as materials that may become liquid at reasonable 1. A mercury vapor lamp comprising a,

light-giving portion, two receiving chambers, a body of mercury between each of said chambers and said vapor path, thus separating them and two leading-in wires adapted to connect with each of said mercury bodies, one or both leading-in wires connecting according to the pressure in the light-giving portion.

A W-shaped tube with mercury sealing the lower angles thereof, means for applying a high voltage alternating current to the mercury in said lower angles, means for overcoming the electrodes surface resistance of said mercury and means adapted to bypass said first named means, said last named means being responsive to the variations of the pressing back of the mercury in the lower angles, resulting from the increase of vapor pressure from operation.

Signed at New York in the county of New York and State of New York this 30" day of October A. D. 1913.

PERCY H. THOMAS.

Witnesses ISABEL W. BONNER, THOS. H. BROWN.

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