Control system

Claim 2

In a machine installation comprising a rotodynamic pump, a steam prime mover having a drive shaft drivingly connected to the pump, a fluid inlet to the pump and a fluid discharge from the pump supplying pressurised fluid to a receiver, and a steam supply line to the prime mover: a control arrangement for the prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including an actuator for regulating the opening of the steam valve; a power line supplying power to said actuator; a control relay in said power line settable to control the power supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure, and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions, and a comparator for comparing a sensed fluid condition value with a desired value and connected to said control relay by a primary conduit whereby a control signal based on the comparison is delivered from the comparator to the control relay for setting of the relay to control the speed of the prime mover and consequently the fluid pressure in said fluid discharge; and secondary control apparatus including a circuit having switch devices arranged in series and connected to sensors sensing further operating conditions in the machine installation, a power source connected to said circuit for energisation of the circuit when the switch devices are in a closed position, an on-off switch in said primary conduit operatively connected to said circuit whereby if a switch device is moved to an open position due to one of said further operating conditions being unsatisfactory the circuit is automatically deenergised and the on-off switch in the primary conduit consequently actuated to interrupt the transmission of the control signal to the control relay and thereby cause stoppage of the prime mover.

Claim 3

In a machine installation comprising a rotodynamic pump, a steam prime mover having a drive shaft drivingly connected to the pump, a fluid inlet to the pump, and a fluid discharge from the pump supplying pressurised fluid to a receiver, and a steam supply to the prime mover: a control arrangement for the prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including a pneumatic actuator for regulating the opening of the steam valve; a power line supplying compressed air to said pneumatic actuator; a control relay in said power line settable to control the air supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions; a comparator for comparing a sensed fluid condition value with a desired value and producing a control signal Based on the comparison; and a primary conduit for delivering the control signal from the comparator to the control relay to set the relay and to control the speed of the prime mover; secondary control apparatus including sensors sensing further operating conditions in the machine installation, an on-off switch in said primary conduit operatively connected to said sensors of the secondary control apparatus to interrupt the transmission of the control signal to the control relay when any of said further operating conditions are unsatisfactory, and a pneumatic discharge valve is provided in said power supply line and is operatively connected to a sensor sensing the speed of the prime mover drive shaft for rapid closure of the steam valve when the speed of said drive shaft increases above a predetermined value.

Claim 4

In a machine installation comprising a rotodynamic pump, a steam prime mover having a drive shaft drivingly connected to the pump, a fluid inlet to the pump, and a fluid discharge from the pump supplying pressurised fluid to a receiver, and a steam supply to the prime mover: a control arrangement for the prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including a pneumatic actuator for regulating the opening of the steam valve; a power line supplying compressed air to said pneumatic actuator; a control relay in said power line settable to control the air supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions; a comparator for comparing a sensed fluid condition value with a desired value and producing a control signal Based on the comparison; and a primary conduit for delivering the control signal from the comparator to the control relay to set the relay and to control the speed of the prime mover; secondary control apparatus including sensors sensing further operating conditions in the machine installation, an on-off switch in said primary conduit operatively connected to said sensors of the secondary control apparatus to interrupt the transmission of the control signal to the control relay when any of said further operating conditions are unsatisfactory, and a pneumatic discharge valve is provided in said power supply line and is operatively connected to a sensor sensing the speed of the prime mover drive shaft for rapid closure of the steam valve when the speed of said drive shaft increases above a predetermined value.

Claim 5

In a machine installation comprising a rotodynamic pump, a steam prime mover having a drive shaft drivingly connected to the pump, a fluid inlet to the pump and a fluid discharge from the pump supplying pressurised fluid to a receiver, and a steam supply line to the prime mover: a control arrangement for the prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including an actuator for regulating the opening of the steam valve; a power line supplying power to said actuator; a control relay in said power line settable to control the power supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure, and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions, and a comparator for comparing a sensed fluid condition value with a desired value and connected to said control relay by a primary conduit whereby a control signal based on the comparison is delivered from the comparator to the control relay for setting of the relay to control the speed of the prime mover and consequently the fluid pressure in said fluid discharge; and secondary control apparatus including switching devices operatively coupled to sensors sensing further operating conditions in the machine installation, an on-off switch in said primary conduit operatively connected to said switching devices whereby if any of said further operating conditions are unsatisfactory the on-off switch is actuated to interrupt the transmission of the control signal to the control relay and thereby cause closure of the steam valve and stoppage of the steam prime mover.

Claim 6

In a machine installation comprising a rotodynamic pump, a steam prime mover having a drive shaft drivingly connected to the pump, a fluid inlet to the pump and a fluid discharge from the pump supplying pressurised fluid to a receiver, and a steam supply line to the prime mover: a control arrangement for the prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including an actuator for regulating the opening of the steam valve; a power line supplying power to said actuator; a control relay in said power line settable to control the power supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure, and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions, and a comparator for comparing a sensed fluid condition value with a desired value and connected to said control relay by a primary conduit whereby a control signal based on the comparison is delivered from the comparator to the control relay for setting of the relay to control the speed of the prime mover and consequently the fluid pressure in said fluid discharge; and secondary control apparatus including switching devices operatively coupled to sensors sensing further operating conditions in the machine installation, an on-off switch in said primary conduit operatively connected to said switching devices whereby if any of said further operating conditions are unsatisfactory the on-off switch is actuated to interrupt the transmission of the control signal to the control relay and thereby cause closure of the steam valve and stoppage of the steam prime mover.

Claim 7

A control arrangement as claimed in claim 3, in which one of the sensors of the secondary control apparatus is additionally coupled to a further switch in the power supply line whereby in the event of the sensed condition rising above a predetermined value, said further switch is actuated to cut-off the power supply to the actuator and thereby effect prompt stopping of the prime mover.

Claim 8

A control arrangement as claimed in claim 4, in which said one sensor is a sensor sensing the shaft speed of the prime mover.

Claim 9

A control arrangement as claimed in claim 3, wherein the actuator of the steam valve controller is a pneumatic actuator and a source of pressurised operating air is connected by a conduit to said pneumatic actuator, the control relay regulating the flow of operating air to the actuator, and the primary control apparatus is comprised by pneumatic devices whereby the control signal is constituted by an air pressure signal, said on-off switch in the primary conduit being comprised by a fluid switch.

Claim 10

A control arrangement as claimed in claim 6, wherein the secondary control apparatus is comprised by a pneumatic circuit including a plurality of fluid switching devices arranged in series in the circuit, each sensor being operatively connected to a respective fluid switching device, said pneumatic circuit being connected to the fluid switch In the primary conduit, whereby on actuation of any of said fluid switching devices the air pressure signal to the control relay is interrupted.

Claim 11

In a machine installation comprising main and standby rotodynamic pumps, steam prime movers each having a drive shaft drivingly connected to a respective pump, a fluid inlet to each pump and a fluid discharge from each pump supplying pressurised fluid to a receiver, and steam supply lines to each prime mover: a control arrangement for each prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including an actuator for regulating the opening of the steam valve; a power line supplying power to said actuator; a control relay in said power line settable to control the power supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure, and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions, and a comparator for comparing a sensed fluid condition value with a desired value and connected to said control relay by a primary conduit whereby a control signal based on the comparison is delivered from the comparator to the control relay for setting of the relay to control the speed of the prime mover and consequently the fluid pressure in said fluid discharge, secondary control apparatus including a circuit having switch devices arranged in series and connected to sensors sensing further operating conditions in the machine installation, a power source connected to said circuit for energisation of the circuit when the switch devices are in a closed position, an on-off switch in said primary conduit operatively connected to said circuit whereby if a switch device is moved to an open position due to one of said further operating conditions being unsatisfactory the circuit is automatically deenergised and the on-off switch in the primary conduit consequently actuated to interrupt the transmission of the control signal to the control relay and thereby cause stoppage of the turbine; and control means in the circuit of the secondary control apparatus of each of the main and standby pumps operatively connected to the secondary control circuit of the other of the pumps, each control means being selectively settable to energise the secondary control circuit of the standby pump on shut-down of the main pump, thereby permitting the standby pump to be started.

Claim 12

In a machine installation comprising main and standby rotodynamic pumps, steam prime movers each having a drive shaft drivingly connected to a respective pump, a fluid inlet to each pump and a fluid discharge from each pump supplying pressurised fluid to a receiver, and steam supply lines to each prime mover: a control arrangement for each prime mover including a steam valve in said steam supply line controlling the steam flow to the prime mover; a controller including an actuator for regulating the opening of the steam valve; a power line supplying power to said actuator; a control relay in said power line settable to control the power supply to the actuator; primary control apparatus serving to ensure that fluid is supplied from the pump to the receiver at a required pressure, and including indicating means sensing any of the pressure and flow rate conditions of the fluid in said fluid discharge, the indicating means generating signals proportional to the sensed fluid conditions, and a comparator for comparing a sensed fluid condition value with a desired value and connected to said control relay by a primary conduit whereby a control signal based on the comparison is delivered from the comparator to the control relay for setting of the relay to control the speed of the prime mover and consequently the fluid pressure in said fluid discharge, secondary control apparatus including a circuit having switch devices arranged in series and connected to sensors sensing further operating conditions in the machine installation, a power source connected to said circuit for energisation of the circuit when the switch devices are in a closed position, an on-off switch in said primary conduit operatively connected to said circuit whereby if a switch device is moved to an open position due to one of said further operating conditions being unsatisfactory the circuit is automatically deenergised and the on-off switch in the primary conduit consequently actuated to interrupt the transmission of the control signal to the control relay and thereby cause stoppage of the turbine; and control means in the circuit of the secondary control apparatus of each of the main and standby pumps operatively connected to the secondary control circuit of the other of the pumps, each control means being selectively settable to energise the secondary control circuit of the standby pump on shut-down of the main pump, thereby permitting the standby pump to be started.

Claim 13

A control arrangement as claimed in claim 8, wherein the actuator of the steam valve controller is a pneumatic actuator and a source of pressurised operating air is connected by a conduit to said pneumatic actuator, the control relay regulating the flow of operating air to the actuator, and the primary control apparatus is comprised by pneumatic devices whereby the control signal is constituted by an air pressure signal, said on-off switch in the primary conduit being comprised by a fluid switch.

Claim 14

A control arrangement as claimed in claim 9, wherein the secondary control apparatus is comprised by a pneumatic circuit including a plurality of fluid switching devices arranged in series in the circuit, each sensor being operatively connected to a respective fluid switching device, said pneumatic circuit being connected to the fluid switch in the primary conduit whereby on actuation any of said fluid switching devices the air pressure signal to the control relay is interrupted.

Claim 15

A control arrangement as claimed in claim 10, wherein said control means is a pneumatic control selectively settable to pass a pneumatic signal from the secondary control apparatus of the main pump to the secondary control circuit of the standby pump for pressurisation of the circuit on shut-down of the main pump, whereby the prime mover of the standby pump may be started.