US1613259A - Railway-track-circuit regulation - Google Patents

Description

1921 2 Sheets-Sheet 1 C.- H. ZIEIRDT M 9 H v r0 RAILWAY TRACK CTRCUIT REGULATION original F'ild Sept 30,

Jan. 4 1927.

. INVENTOR. & F? I (Q Z M 1 ATTORNEY Jan. 4, 1927. ,613,259

, A c. H. ZIERDT;

RAILWAY TRACK CTRCUIT REGULATION Filed se ix so. 1921 2 Sheets-Sheet 2 5 i WY E94.

D 21 I23: I

INVENTOR'. CAN.

A'l 'ToRNEY Patented Jan. 4, 1927.

UNITED STATES PATENT;

CONRAD H. ZIERDT, OF PENN 'IOVVNSHIIP, ALLEGHENY COUNTY, PENNSYLVANIA, AS- SIGNOR TO THE UNION SWITCH 86 SIGNAL COMPANY, OF SWISSVALE, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAOK-CIRCUIT REGULATION.

My invention relates to track circuits for railways, and has for an object the provision of means for stabilizing the voltage across the rails in such circuits.

The present application is a continuation of my co-pending application filed Sept. 30, 1921, Serial No. 504321, for railway track circuit regulation, in so far as the sub ect matter common to the two is concerned.

I will describe several forms of apparatus embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 1s a'diagrammatic view showing one form of apparatus embodying my invention, and Figs. 2, 3, 4t, 5, 6, 7 and 8 are views showing modifications of the apparatus shown in Fig. 1 and also embodyingmy invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the reference character A designates a section of railway track which is electrically separated from the adjoining portions of track by insulated joints 12. The section A is provided with a track circuit comprising the track rails 2 and 2, a transformer secondary 3 connected across the rails at one end of the section, and a relay R having a winding l connected across the rails at the other end of the section. The primary 5 of transformer T is, of course, connected with a suitable source of alternating signaling current which is not shown in the drawing.

In a combination such as that just described, it is desirable that the voltage across the terminals of the relay winding 1 should be as nearly constant as possible, but in actual practice this voltage varies for a number of reasons, one of which is that the electrical resistance of the ballast between the rails 2 and 2 is lower in wet weather than in dry weather, so that the voltage across the relay winding is lower in wet than in dry weather, assuming the voltage at the transformer end of the section to be constant.

In order to stabilize the voltage at the relay R,I provide the track circuit with a reg ulator B comprising a heating element 6 connected across the rails 2 and 2 and a therino sensitive element 7 also connected across This application filed December the rails and exposed to variations in the temperature of the heating element 6. Element 7 is also in electrical contact with element 6. The thermo-sensitive element 7 has the characteristic of decreasing in electrical resistance with increase of temperature, that is, it has a negative temperature coefficient. As here shown, the regulator is located at about the middle of the track circuits, but I. do not desire to be limited to this specific location.

.The parts of the track circuit, including the regulator 3,1 are so adjusted that in wet weather the voltage at relay winding 4 is the desired or normal value. Then as the ballast dries out, the ballast resistance increases so that the voltage across the heating element 6 increases, with the result that the amount of current flowing in this element increases and the temperature of this element rises. This causes the resistance of the thermo-sensitive element to decrease, so that more current flows from rail ,to rail through this element, thereby lowering the voltage across the rails. It follows that the voltage applied to relay R is more nearly constant than it would be without the regulator.

Referring now to Fig. 2, the regulator, which is here designated C, comprises a compression rheostat 8 in the form of a pile of carbon discs connected across the track rails 2 and 2", a magnet 9 also connected across the rails, and an armature 1O controlled by by a rod 11. The electrical resistance of the rheostat decreases with increase. in the pressure exertedthereon iby armature 10, and, of course, this pressure increases with increase of current in the magnet winding, that is, with increase of voltage across the rails. It follows thatas the rail voltage increases, the resistance of the rheostat decreases, and so the regulator tends to stabilize the voltage applied to relay winding 4. As with the apparatus shown in Fig. 1, the parts are so ad justed that normal voltage is applied to relay winding 4 when the rail ballast is wet.

In Fig. 8, the regulatorC is the same as in Fig. 2, but the rheostat and magnet winding are connected in series across the track rails instead of in multiple as shown in Fig. 2.

the magnet and connected with the rheostat The operation is the same as that of the apparatus shown in Fig. 2.

Referring to Fig. 4-, the regulator, here designated by the reference character B, comprises a cylindrical conductor 13. Covering this conductor and attached thereto is a coating of thermo-sensitive material 7. The heating element 6 comprises a coil of wire wound around the outside of this therino-sensitive element and in contact therewith. The rail 2 is connected to one end of the heating element 6 and to the conductor 13 while the other end of the heating element 6 is connected to the rail The operation of this regulator is precisely the same as that of the regulator shown in Fig. 1.

In Fig. the regulator B" comprises two conductors let and 15 of some conducting material such as nickel, plated with copper, which are helically wound or intertwined into a hollow tube in such a manner that the turns of one conductor alternate with the turns of the other. Each conductor is covered with a coating of thermo-sensitive material such as copper oxide, which is thus interposed between one conductor and the other. This coating may be conveniently applied by heating the copper-plated conductors after they have been Wound together. Spaced in the tube formed by these conductors is a heating element 16 having its terminals connected to the conductors 1-61 and 15, respectively. The rail 2 is connected to one conductor 15 and rail 2 is connected to the other conductor 14. Now if the track voltage rises, the amount of current flowing in the heating element 16 increases thus rais ing the temperature of this element. The heat so generated causes the temperature of the thermo-sensitive material on conductors 14.- and 15 to increase, so that more current is allowed to pass from one conductor to the other, that is. from rail to rail through the thern'io-sensitive material, thereby tending tolower the voltage across the rails. The result is a decrease in the voltage fluctuation at the relay R. i

The resistance of thermo-sensitive cells is normally very high except at high temperatures, and so in some cases it is desirable to operate these cells at higher voltages than are available in track circuits. As shown in Fig. 6, I accomplish this by means of a step up transformer T. The primary winding 17 of this transformer is connected across the rails of section A. and the terminals of the secondary winding 18 are connected to two electrodes 21 of a thermo-sensitive cell D. Between these two electrodes is a high resistance element of thermo-sensitive material such as a compressed mixture of pulverized copper oxide and silicate of sodium. hen the voltage on the track increases, the voltage applied to the thermo-sensitive element 20 also increases. This causes an increased current to flow through the element 2 1 which results in a decrease in its resist ance and a still greater increase in the current passing through this element. This results in a greater current from rail to rail through winding 17 and the voltage is consequently more nearly constant at relay R than it would be without the regulator.

The main advantage of the apparatus shown in Fig. 6 is that since the thermosensitive cell is operated at higher voltages than those ordinarily available in track circults, this cell can be made more rugged mechanically than a cell which must ope "ate on ordinary track circuit voltages. Furthermore, owing to the comparatively high voltage applied to the cell the heater coil is probably not necessary, but if found desirable the thermo-sensitive action of the cell may be increased, as shown in F '7, by means of a heater coil 19 connected across the rails and so disposed that the heat generated in it serves to raise the temperature oi the thermosensitive element 20. The structure and operation of the regulator are otherwise the same as o t'thatshown in Fig. 6.

In Fig. 8 the regulator 13 of Fig. 5 is substituted for the regulator D of Fig. 6. Its action is exactly as before but the operating range is increased by the higher voltage supplied by the transformer T.

Apparatus embodying my invention as shown in Figs. 1-5 inclusive may be applied to either direct current or alternating current track circuits, but when applied to an alternating current circuit it should be noted that the regulator B or C does notdisturb the phase relations of the system because the current flowing in the thermo-sensitive element 7 of Fig. l and in the compression rheo-statelement 8 of Figs. 2 and 3 is practically in phase with the leakage current in the rail ballast. Furthermore. inasmuch as these regulators stabilize the leakage current between the rails, they also stabilize the phase of the current delivered to the track relay, that is, theytend to eliminate the va riations in phase due to variations in conductivity of the track ballast.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a track circuit comprising the track rails of a railway and a track relay connected across said rails, a heating element connected across said rails in multiple with said relay, and a thermosensitive element also connected across said rails in multiple with said relay and exposed to variations in the temperature of said heating element.

2. In combination, a track circuit comprising the track rails of a railway and a track relay connected across said rails, and a thermo-sensitive relay comprising a heating element and a thermo-sensitive element both of which are connected across said rails in multiple with said relay.

3. In combination, a track circuit comprising the track rails of a railway and a track relay connected across said rails, and

a thern'io-sensitive relay comprising a heatin;' element and a thermo-sensitive element both of which are connected across said rails in multiple with said relay, said then mo-sensitive element havingthe characteristic ot decreasing in electrical resistance as its temperature increases.

i. In combination, a track circuit conr rising the track rails of a railway and a track relay connected across said rails, a thern'io-sensitive element connected across said ri ils in multiple with said relay, and a heating element also connected across said rails in i'nult-iple with said relay for varying the temperature of said tliermo-sensitive element in response to variations in the voltage across said rails.

5. In combination, a track circuit comprising the track rails of a railway and a relay, a conductor connected across said rails, and means responsive to variations in the current carried by said conductor for stabilizing the voltage across said rails.

6. In combination, a track circuit cornprising the track rails of a railway and a relay, a conductor connected across said rails in multiple with said relay, and a device connected across said rails in multiple with said relay and having the characteristic of varying in electrical resistance in response to variations in the current carried by said conductor.

7. In combination, a section of railway track, a track circuit for said section co1nprising a source of current and a relay both connected across the rails of the section, a thermo-sensitive substance, two conductors in contact with said substance and connected with the two rails respectively of said section, and an element connected across said rails for heating said substance.

8. In combination, a section of railway track, a track circuit for said section comprising a source of current and a relay both connected across the rails of the section, two helical conductors connected with the two rails respectively of said section and so disposed that the turns of one alternate with the turns of the other, a coating of thermosensitive sul'istance on each conductor, and an element connected across said rails for heating said substance.

9; In combination, a track circuitconr prising the rails oi a railway, a conductor connected acros said rails, an electrode connected to one of said rails, a second electrode connected to the other of said rails, and an element of thermo-sensitive material interposed between said electrodes and responsive to variations in the current carried by said onductor.

10. In combination, a track circuit comprising the rails of a railway, a conductor connected across said rails, an electrode connected to one of said rails, a second electrode com'iccted to the other said rails, and an element of tl'iermo-sensitive material interposed between said electrodes and responsive to variations in the temperature of the said conductor.

In testimony whereof I ailix my signature.

CONRAD H. ZIERDT.

Images