US1715895A - Control instrument - Google Patents

Description

June 4, 1929. p BROWN ET AL CONTROL I NSTRUMENT Filed Jan. 21, 1926 I lgrfofi/cx 144 5/05 M a M/MMZ ATTORNEY Patented June 4, 1929.

UNITED STATES PATENT OFFICE.

RICHARD P. BROWN AND FREDERICK W. SIDE, OF PHILADELPHIA, PENNSYLVANIA,

ASSIGNORS TO THE BROWN INSTItUINIENT COMPANY, OF PHILADELPHIA, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

CONTROL INSTRUMENT.

. Application filed January 21, 1926. Ser-iaf No. 82,881.

Our present invention relates to instruments such as pyrometer controllers in which a galvanometer or like sensitive control clement exercises a control function through a relay mechanism.

The general ob'ect of the present invention is to provi e improved means characterized by their practical simplicity and effectiveness for making the extent of adjustment of the relay mechanism controlled by a control instrument of the type specified, dependent on the extent of deflect1on of the control element of the instrument. A more specific object of the invention is'to provide an effective control instrument com ris ng a deflecting meter element, and mec anism periodically engaging the deflecting meter element and momentarily restraining its deflection, for selectivel energizing one or another of a plurality 0 control circuits, or other control elements, depending upon the position of the deflecting meter element at the time of each such engagement, and for maintaining the energization of each control element so energized after the deflecting meterelement is released and for a predetermined time interval which is difierent for the different control elements.

The various features of novelty which characterize our invention are pointed out with articularity in the claims annexed to and orming a part of this specification.

For a better understanding of our invention,

however, its specific objects and advantages attained with it, reference should be had to .the accompanying drawings and descri tive matter in which we have illustrated an described a preferred embodiment of our.

invention.

The one figure of the drawing is a diagrammatic representation of an oil still control system.

In the drawing we have diagrammatically illustrated the use of our invention in controlling the rate of combustion in an oil refiningstill in such manner as to maintain an approximately constantntemperature at the oil exit from the still. As shown, the still A comprises a bankof tubes B through which the oil is passed. The tubes B are located above a combustion chamber A to w ich fluid fuel under pressure is supplied a a rate dependent upon the adjustment of a regulating valve C. The regulating valve C' is adjusted by a reversible motor D to increase the amount of fuel suppliedto the burner C when the oil in contact with a theI'mo-couple E in a thermometer well B at the still oil exit falls below a predetermined temperature, and when the oil passing through the well B increases in temperature above the predetermined temperature, the motor D is operated to throttle the flow of oil to the burner C.

The means provided for controlling the motor D in response to the temperature to which the thermo-couple E is subjected includes a controller comprising a voltmeter F to which the terminals of the thermocouple E are connected and having a pointer shown as of the so-called electric clock type,

and having a rotating shaft I. The latter carries a cam I which normally engages a tooth G on a bar G attached to the pivoted depressor G and thereby holds the bar in a lower position in which the depressor G is held out of contact with the pointer F. Once in each rotation of the cam I, the tooth G enters the notch I in the cam I and the depressor G tilts downward under the action of gravity and depresses the pointer F and thereby closes one or another of the pairs of contacts L, Z, L, Z, H, h, and H h, provided the pointer F is above any one of said pairs of contacts when depressed. Whenv either of the contacts H, h, or H, 71;, are closed, the motor D is energized to rotate in the direction required to decrease the oil supply to the burner C, and when either pair of contacts L, Z, L, Z, are closed by the pointer F, the motor D is energized to rotate in the direction required to increase the flow of fuel to the combustion chamber through the burner C. In accordance with the present invention the time during which the motor Dis energized, and consequently the extent of adjustment given by the motor to the valve C is greater when the contacts L, Z','or H, h, are closed by the pointer F, than when the contacts L, Z,or H, h, are closed by the pointer.

The energization of the motor D is effected by means of switches operated by electromagnets M", M", M, and M, which are energized when the pointer depresses the contacts h, 71., Z, Z, respectively, and the period during Which the motor is energizedfollowing each such contact depression is controlled by a timing switch S. 'Whenany one of the electro-magnets M", M, M, and M is energized its energization results in closing an auxiliary holding-in circuit whereby the energization of the electro-magnet is maintained after the contacts H, h, H, k, etc. which were closed to effect such energization have again separated. The timing switch S effects the de-energization of each of the electro-magnets by closing a shunt about the latter.

As shown, the motor D is a three-phase motor having one terminal 15 permanently connected to one of the conductors 3 of a three-phase alternating current supply system. The other two motor terminals 13 and .14 are connected to the supply conductors land 2 respectively, when either of the magnets M and M is energized, and are connected to the supply conductors 2 and 1 respectively, when either of the magnets M and M is energized by circuit connections now to be described.

As shown, each of the contacts Z, Z, k, and h, 'is connected to the supply conductor 2 by a conductor 4. The contact H is connected to one terminal of the magnet M by a conductor 5. Similarly, the contacts H, L, and L, are connected by conductors 6, 7, and 8, respectively, each to one terminal of the corresponding magnet M, M, and M The second terminals of the magnets M and M are connected by a conductor 9, limit switch 0, resistance R, andconductor 11, to the supply conductor 1. The second terminals of the magnets M and M are connected by the conductor 10, limit switch 0, and resistance R to the conductor 11 and thereby to the supply conductor 1. The limit switches O and O are normally closed, but an arm D" is rotated by the motor D into position to open the switch 0 when the valve C is adjusted into its wide open position, and the arm D is rotated into position to open the limit switch 0 when the valve C is adjusted into its fully closed position. The limit switches thus serve the usual function of such switches in control apparatus of limiting the mechanism'movement in each direction.

Each of the magnets M, M", M, and M is provided withan individual armature M pivoted at M. Associated with the magnets M and M is a switch member Q, pivoted at Q, and carrying two contacts 9 and 9. When either of the magnets M and M is energized, the corresponding armature M engages the switch member Q, and depresses the latter into the position in which the contact q connects a branch 13A of the motor terminal 13 to a branch 1A of the supply conductor 1, while at the same time the contact q connects a branch 14A of the motor terminal 14 to a branch 2A of the supply conductor 2. Associated with the magnets M and M is a switch member R similar to the switch member Q. and depressed when either of the magnets M and M is energized. The switch member R carries two contact members 1' and 1". When the switch member R is depressed, by the energization of either magnet M or M, the contact 9 connects a branch 13B of the motor terminal 13 to a branch 2B of the supply conductor 2 and at the'same time the contact r connect-s a branch 14B of the supply conductor 2 to a branch 1B of the supply conductor 1.

The armature M of the electro-magnet- M is provided with a contact M connected to the same terminal of the electro-magnet M as is the conductor 5, and brought into engagement with a co-operating contact connected to'the conductor 40 when the magnet M is energized. The conductor 40 is a branch of the conductor 4 and in consequence when the closure of the contacts H and I1. energizes the winding M and connects the corresponding contact M 'to the conductor 40, the subsequent separation of the contacts H and h does not de-energize the magnet M Similarly, each of the other armatures M is provided with a contact M engaging a contact connected to the conductor 40 and closing a holding-in circuit for the corresponding magnet when the latter is energized.

As already explained. the de-energization of the electro-magnets M, M, M, and M is controlled by the time switch S. The latter, as shown, is a body of conducting material carried by a frame S pivoted at S, and oscillated by a cam I carried by the shaft I of the electric clock or timing motor I. The oscillating switch member S is connected by a conductor 16 to the terminal of the resistance R which the limit switches O and O normally connect to the conductors 10 and 9, respectively. Associated with the movable switch member S are contacts S S, S, and S, which are connected to the conductors 5, 6, 7, and 8 respectively. The contacts S and S are in position to be engaged by the switch member S, a short period after the movement of the motor I into the position in which it depresses the pointer F. The period at which such engagement occurs may be adjusted by adjusting the position of the contact arms S and S relative to the path of oscillation of the switch member S. As

arm S carrying the contacts S and S. Similarly the contacts S and S may be adjusted by adjusting their supporting arm S. S represents clamping screws by which the arms S and S* may be clamped in their different adjustments.

In operation the pointer F is depressed at regular intervals of thirty seconds or so. \Vhen at any depression of the pointer F,

the temperature of the thermo-coup'le Eis slightly above the normal or predetermined temperature the contacts H and h are closed,

while if the thermo-couple E is still hotter the contacts H and h areclosed. sure of either pair of contacts H andh, or H and h, sets the. motor D into rotation in the direction to close the valve C and de crease the'supply of fuel to the combustion chamber A. Conversely, a small or large decrease of the temperature of the thermocouple E below normal closes the contacts L and Z or L" and Z respectively and thereby causes the motor D to rotate in .the direction to increase the fuel supply to the chamberv A. Then either pair of contacts H and h, or L and Z are closed, the resultant energization of the motor D continues for a period of five seconds say, which depends on the adjustment of the arm S untilthe of the statutes, we have illustrated and de-- scribed the best form of embodiment of our invent-ion now known to us, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of our invention as set forth in the appended claims and that in some cases certain features of our invention may be used to advantage without a corresponding use of other features.

Having now described our invention what we claim as new and desire to secure by Letters Patent, is:

1. In a control instrument comprising a deflecting element, a plurality of control circuits each including an electro-magnet,

means operative at regular intervals to energize one or another circuit dependent on the then position of said deflecting element, a holding in circuit .associated with each magnet closed and preserving the energization of the latter when energized by the first mentioned means, and means for deenergizing said magnets each at a prede- The clotermined interval following its energization, I

the last mentioned interval being different for different magnets.

2. In a control instrument, the combination with a deflecting element, of a plurality of control circuits and circuit controlling mechanism including periodically operating means cooperating with said element for a brief period at regularly recurring intervals to selectively energize one or another of said circuits depending on the position, of said element and including means for maintaining the energization of each circuit so energized for a predetermined period which. is different in the case of the different circuits and 'in each case is longer than one of the first mentioned intervals and is independent of the position of the element subsequent to said energiz'ation. v e

3. In a control instrument, the combination with, a deflecting element, of a plurality of controlcircuits, energizing mechanism for said circuits including periodically actuating vmeans momentarily engaging said element and thereby selectively determine which of one or another of said circuits is to be energized dependent upon the position of gsaid element when so engaged, and other means cooperating with the "first mentioned means to energize the circuit selected and to maintain its energization for a predetermined period which is dependent on the position of said element when so engaged,

ut is independent of the eriod of such engagement, and is different or the different circuits and in all cases is longer than each period of engagement of said deflecting element and the first mentioned means. v

4. In a control instrument, the combina-,

tion with a deflecting meter element normally free to deflect, of a plurality of control ele- 'ments,.meehanism including means periodically engaging said meter element and momentarily restraining the latter from deflecting, for selectively energizing one or another of said control elements, depending on the position of said meter element at each such engagement, and means associated with the various control elements for maintaining the energization of each element so energized after the meter element is released for a predetermined time interval which is different for different control elements.

5. In a control instrument, the combination with a deflecting meter element normally free to deflect, of a plurality of control elements, mechanism including means periodically engaging said meter element and momentarily restraining the latter from deflecting, for selectively energizin one or another of said control elements epending on the position of said meter element at each such engagement, and means associated with the various control elements for maintaining the energization of each element so energized after the meter element is released for a predetermined time interval which is different for different control elements, said last mentioned means including a time controller for controlling the time of operation of said mechanism.

6. In a control instrument, the combina tion with a deflecting meter element normally free to deflect, of a plurality of control elements, mechanism including means periodically engaging said meter element and momentarily restraining the latter from deflecting, for selectively energizing one or another of said control means depending on

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