US1738072A - Means for controlling the supply of a driving fluid, the pressure of a fluid, and similar purposes - Google Patents

Description

Dec. 3, 1929. T, KALLE 1,738,072

MEANS FoR CONTROLLING THE SUPPLY OF A DRIVING FLUID, THE PRESSURE OF A FLUID, AND SIMILAR PURPOSES Filed D60. 28, 1923 13109112721 T Kalle lit Patented Dec. 3, 1929 UNITED STATES TORSTEN KALLE, OF SAFELE, SWEDEN MEANS FOR CONTROLLING THE SUPPLY OF A DRIVING FLUID, THE PRESSURE A FLUID, AND SIMILAR PURPOSES Application filed December 28, 1923, Serial No. 683,261, and in Sweden January 2, 1928.

.the carrier, the parts at each side being connected with a mounting common to the same, the said mountings preferably comprising a stationary support and a movable member to which, 'lor example, a valve or the like to be controlled is connected. Dwing to this arrangement the conductor will have a tensile strength equal to the sum of the tensile strengths of all the parts thereof, so that the device may directly operate even a heavy valve or the like to be controlled.

ln the accompanying drawing Figure 1 shows one example of the electro-thermic device combined with a servo-motor for controlling the pressure in a steam conduit. Figure 2 shows a side view of the electro-thermic device together with a Bourdon-tube and a contact device for effecting the control. Figure 3 is a plan view of the electro-thermic device.

The electro-thermic device comprises a bare conductor 41, which for the necessary turns is wound round a plate 42 and insulated from the same, the plate being provided with notches for supporting the conductor. The top parts of the conductor 41 are connected with an insulating member 43, fixed to a casing 40 of inverted L-shape (Fig. 1) enclosing the controlling device, while the lower parts of the conductor are fixed to another insulating member 44. By a .spring device acting upon the-member 44, the parts of the wire 41 are subjected to a straining action, so that the upper set of parts and the lower set of parts of the conductor form preferably acute angles with each other as shown in Figure 2. As an electric current of varying strength or elec tric impulses passes through the conductor 41, the temperature of the latter varies, which results in the length of the conductor being changed, so that the member 44 is moved towards the member 43 or from the same. In the controlling device shown in the drawing the movement of the member 44 is used for operating a valve 9, which controls the discharging ot the pressure liquid from a servomotor 1. The servo-motor comprises a cylinder provided with a supply pipe for pres" sure-liquid and a piston, the rod out which by a wire 2, chain or the like is connected with the valve oi a steam conduit 50. A counter-weight 7' tends to move the valve towards its closed position. Member 44 car ries a bolt 45 in screw-threaded engagement with a nut 46. Between the nut 46 and the bottom wall of the casing 40 a coil spring '47 is provided. By means of the nut 46 the tension of the spring 47 and thus the tension of the parts oi the conductor 41 may be adjusted. Nut 46 has a pin 46 bearing against the spindle of the valve 9. The latter is so arranged, that it may be opened to a greater or less extent by the pressure liquid of the servo-motor it against the action of the spring 47. The distance for which the valve is opened is determined by the electro-thermic device, as will be explained hereinafter.

A Bourdon-tube 48 communicates through a pipe 49 with the steam-pipe 50. A twoarmed lever 51 is pivoted to the free end of the tube 48 and carries at its one end an arm 52 provided with a contact 58 for instance of copper, which co-operates with a contact 54 for instance of carbon. Contact 54 is fixed to the carrier 42 and connected with one of the ends of the conductor 41. The other end of the conductor 41 is connected with the socket 57 of a plug, connected for instance with the positive lead of a source of current, while the negative lead is connected with the casing 40 or the arm 52. To the other end oi the arm 51 a spring is connected, which may be adjusted by a screw 56. By changing the tension of the spring 55 the steam-pressure is adjusted, for which the device ought to eilect its controlling action. The distance between the contacts 53, 54 is adjusted by means of a screw 58, provided on the arm 52 and bearin against the tube 48.

The evice operates in the following manner. If the steam-pressure in the pipe 50 increases, the Bourdon-tube 48 moves the contact 53 from the contact 54. Conductor 41, previously heated by the current, then becomes cooler and conse uently shorter, which results in the pin 46* eing raised and the valve 9, acted upon by the pressure liquid in the servo-motor, being moved into a more open position against the tension of the spring 47. The liquid below the piston of t e servo-motor then escapes for a greater quantity, thus permitting the said piston to move downwards and the weight 7 to move the valve 35 towards its closed osition, so that the pressure of the steam ehind the valve is reduced. By the contraction of the conductor 41 also the plate 42 is raised, which results in the contact device 53, 54 being again closed, provided that the increasing 0 the steam-pressure and thus the raising of the contact 53 was within certain limits. As the contact device is closed, the temperature and the length of the conductor 41 are increased, so that the valve 9 is moved towards its closed position by the spring 47. The pressure liquld then raises the piston of the servo-motor, so that the valve 35 is moved towards its open position and the steamsressure behind the valve and in the Bouron-tube is somewhat increased. This results in a new breaking of the contact-device 53, 54, a new cooling and contraction of the conductor 41, the moving of the valve 9 to a more opened position and so on. The described operations are repeated until a state Y of equilibrium of the members belonging to the controlling device is created and the valve 35 is brought into a position in which the steam-pressure in the tube 50 has been adjusted to the desired amount. The said state of equilibrium will be maintained while the distance between the contacts 53, 54 is increased and decreased alternately. The controlling device operates in an exactly analogous manner if the pressure in the pipe 50 alls below the normal. Valve 9 is then successively moved towards its closed position, so that the servo-motor successively brings the valve 35 into a more open position.

Owing to the fact that the conductor 41 is wound round the carrier 42 for a number of turns, the conductor is so long that it may be connected directly with a network of high tension circuits without a series resistance. At the same time the tensile stren th of the wire is increased, as it is equal to t e sum of the tensile strengths of all the coils, the force exerted by the conductor, when cooled, being thus sufiicient for operating, for instance, the throttling device of a steam conduit directly, without the aid of a servo-motor. Preferably the conductor 41 is so thin, that the changin of its temperature and thus of its length ta es place as nearly momentarily as possible at the changing of the intensity of the current or at the passing of the currentim ulses.

claim:

In an electro-thermic controlling device adapted especially for shifting heavy members such as valves and eflecting great movement of the same the combination of a movable plate-shaped carrier, a conductor wound round the said carrier, a stationary mountin to which the Karts of the conductor locate at the one si e of the carrier are fixed, a movable mounting to which the parts of the conductor located at the other side of the carrier are fixed, and means provided on the mounting last mentioned for the connection of the member to be controlled.

In testimony whereof I have hereunto affixed my signature.

TORSTEN KALLE.

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