Machine installation control system

Claim 2

A control arrangement for a machine installation of the type including a drive machine for connection to a load, and particularly but not exclusively to an installation wherein the drive machine is constituted by a steam turbine, the control arrangement comprising in combination: a. primary indicating means for sensing any of the drive speed of the drive machine and other operating condition prevalent within the installation dependent on the drive speed, the primary indicating means generating signals proportional to the sensed condition; b. a signal generating device settable to produce a signal proportional to the desired value for said sensed condition; c. a comparator including an output for a control signal; d. line means delivering the produced signal from the primary indicating means and the desired value signal from the signal generating device to said comparator whereat the signals are compared and an output control signal produced based on the comparison; e. speed regulating apparatus for the drive machine including i. an actuator having a motor operable for adjustment of the drive machine speed; ii. a power supply line connectible to a power source for supplying power to said actuator motor; and iii. a servo-control device for regulating the power supply to said actuator motor and thereby the operation of the actuator for adjustment of the drive machine speed; f. conduit means for delivering the control signal from the comparator output to the servo-control device for setting of the device so that the desired value for the measured operating condition may be maintained; and g. secondary emergency indicating means including: i. sensing means for sensing any of the drive machine speed and other operating condition within the machine installation, ii. a switch in said power supply line to the actuator motor and movable to an open position to cut-off the supply of power to said actuator motor for prompt stoppage of the drive machine, and iii. connecting means operatively connecting the sensing means to said switch whereby when the operating condition sensed by said sensing means reaches an unsatisfactory value the switch is moved to said open position to stop the drive machine.

Claim 3

A control arrangement as claimed in claim 1, wherein the primary indicating means senses the drive speed of the drive machine.

Claim 4

A control arrangement as claimed in claim 1, wherein the drive machine is a fluid machine, and the speed regulating apparatus comprises a throttle valve to control the flow of operating fluid to the drive machine, and the actuator of the throttle valve is operable by electric power, the switch being an electrical switch.

Claim 5

A control arrangement as claimed in claim 1, wherein the primary indicating means, the comparator and the servo-control device are comprised by electronic devices whereby an electric control signal is delivered to said servo-control device to control the movement of the actuator.

Claim 6

A control arrangement as claimed in claim 3, wherein the actuator of the throttle valve includes a hydraulic device for control of the valve opening, and the speed regulating apparatus additionally includes an electric motor driven machine for supply of pressure fluid to the hydraulic device, electric power to the motor being supplied via said power supply line.

Claim 7

A control arrangement as claimed in claim 4, wherein the secondary emergEncy indicating means includes an electronic warning device having an electrical filter having a characteristic such that up to a predetermined electric input to the filter the filter output is of constant value, but when the input increases beyond the predetermined value the filter output falls sharply, the filter input corresponding to the measured condition, and the filter is operatively connected to a trip relay whereby when the filter output falls sharply when the speed of the drive machine increases beyond the predetermined value, the relay is actuated to open the switch.

Claim 8

A control arrangement for a machine installation of the type including a drive machine for connection to a load, and particularly but not exclusively to an installation wherein the drive machine is constituted by a steam turbine, the control arrangement comprising: a. primary indicating means for sensing any of the drive speed of the drive machine and other operating condition prevalent within the installation dependent on the drive speed, the primary indicating means generating signals proportional to the sensed condition; b. a signal generating device settable to produce a signal proportion to the desired value for said sensed condition; c. a comparator including an output for a control signal; d. line means delivering the produced signal from the primary indicating means and the desired value signal from the signal generating device to said comparator whereat the signals are compared and an output control signal produced based on the comparison; e. speed regulating apparatus for the drive machine including: i. an actuator having a motor operable for adjustment of the drive machine speed, ii. a power supply line connectible to a power source for supplying power to said actuator motor; and iii. a servo-control device for regulating the power supply to said actuator motor and thereby the operation of the actuator for adjustment of the drive machine speed; f. conduit means for delivering the control signal from the comparator output to the servo-control device for setting of the device so that the desired value for the measured operating condition may be maintained; g. secondary emergency indicating means including: i. sensing means for sensing any of the drive machine speed and other operating condition within the machine installation, ii. a switch in said power supply line to the actuator motor and movable to an open position to cut-off the supply of power to said actuator motor for prompt stoppage of the drive machine, and iii. connecting means operatively connecting the sensing means to said switch whereby when the operating condition sensed by said sensing means reaches an unsatisfactory value the switch is moved to said open position to stop the drive machine; and h. a switch closing element for said switch of the secondary emergency indicating means; i. a line connecting said switch closing element to said primary indicating means for the delivery of primary signals to said switch closing element, the switch closing element being actuable by said signals generated by said primary indicating means to close the switch; j. a drive machine start-up setting device including an element movable to a first position to permit start-up of the drive machine and adjustable to a further position for normal running of the machine; and k. over-ride means for said switch closing element operatively connected to said drive machine start-up setting device so that an over-ride signal is produced when the setting device element is moved to said first position for machine start-up, which over-ride signal is eliminated when the setting device element is adjusted to said further position for normal running of the drive machine, the over-ride signal serving for switch closure at drive machine start-up in the absence of a primary signal from the primary indicating means.

Claim 9

A control arrangement for a machine installation of the type including a drive machine for connection to a load, and particularly but not exclusively to an installation wherein the drive machine is constituted by a steam turbine, the control arrangement comprising: a. primary indicating means for sensing any of the drive speed of the drive machine and other operating condition prevalent within the installation dependent on the drive speed, the primary indicating means generating signals proportional to the sensed condition; b. a signal generating device settable to produce a signal proportion to the desired value for said sensed condition; c. a comparator including an output for a control signal; d. line means delivering the produced signal from the primary indicating means and the desired value signal from the signal generating device to said comparator whereat the signals are compared and an output control signal produced based on the comparison; e. speed regulating apparatus for the drive machine including: i. an actuator having a motor operable for adjustment of the drive machine speed, ii. a power supply line connectible to a power source for supplying power to said actuator motor; and iii. a servo-control device for regulating the power supply to said actuator motor and thereby the operation of the actuator for adjustment of the drive machine speed; f. conduit means for delivering the control signal from the comparator output to the servo-control device for setting of the device so that the desired value for the measured operating condition may be maintained; g. secondary emergency indicating means including: i. sensing means for sensing any of the drive machine speed and other operating condition within the machine installation, ii. a switch in said power supply line to the actuator motor and movable to an open position to cut-off the supply of power to said actuator motor for prompt stoppage of the drive machine, and iii. connecting means operatively connecting the sensing means to said switch whereby when the operating condition sensed by said sensing means reaches an unsatisfactory value the switch is moved to said open position to stop the drive machine; and h. a switch closing element for said switch of the secondary emergency indicating means; i. a line connecting said switch closing element to said primary indicating means for the delivery of primary signals to said switch closing element, the switch closing element being actuable by said signals generated by said primary indicating means to close the switch; j. a drive machine start-up setting device including an element movable to a first position to permit start-up of the drive machine and adjustable to a further position for normal running of the machine; and k. over-ride means for said switch closing element operatively connected to said drive machine start-up setting device so that an over-ride signal is produced when the setting device element is moved to said first position for machine start-up, which over-ride signal is eliminated when the setting device element is adjusted to said further position for normal running of the drive machine, the over-ride signal serving for switch closure at drive machine start-up in the absence of a primary signal from the primary indicating means.

Claim 10

A control arrangement as claimed in claim 7, wherein the primAry indicating means is constituted by an electronic tachometer producing an electrical signal proportional to the speed of the drive machine and linked to an electric transducer which is operatively associated with a drive shaft of the drive machine to measure the rotational speed of the shaft, the secondary indicating means includes an electronic device measuring an operating condition in the installation and delivering a warning signal when the said condition rises above a predetermined value, the switch being responsive to said warning signal to close the actuator, said electronic device of the secondary indicating means including a relay element operatively connected to both the primary indicating means and the switch of the secondary emergency control whereby in the event of failure of the tachometer the relay element is actuated in the absence of a signal from the tachometer to open the switch and thereby close the actuator, and said over-ride means is comprised by an electrical device operable by said drive machine start-up setting device to pass an electrical signal to said switch to permit an opening movement of the actuator at start-up of the machine installation.

Claim 11

A control arrangement as claimed in claim 8, wherein said signal generating device includes an electronic setting device for producing a signal proportional to the desired value of the sensed condition, and said over-ride means is included in the setting device to operate when the setting device is set at a predetermined value position.

Claim 12

A control arrangement as claimed in claim 7, wherein the primary indicating means includes a speed limiting device operable at start-up of the drive machine, when said over-ride means are operable, to limit the build up of speed by the machine.