System for controlling pump operation

Abstract: Characterised by, preferably in the area of fluid suction towards the pump (1), the presence of a detector device (3) for the pressure of the fluid in said area, which device, in the event of a variation in pressure or vacuum in this area, transmits a signal to the pump (1) which will cause same to shut down. This device (3) comprises a pressure switch-vacuum switch or a pressure gauge which transmits an electrical signal to a relay operating the pump (1). This system comprehends at least one timer which will program pump operation down time. In addition, the system includes at least one signal microprocessing circuit and one system restarting monitoring subsystem.

Description: The invention refers to an apparatus for controlling pump operation. Purpose of the invention This apparatus is intended mainly for controlling and ensuring the safe operation of hydraulic pumps of the type installed in swimming-pools, fountains and other places where water is held, in order to suck it and circulate it through hydraulic circuits, such as filter or pumping circuits in aqua-parks (with slides and other complements) the water subsequently being sent towards the original tank or another. Background to the invention Drains are installed at the bottom of, or next to, swimming-pools, fountains, reservoirs and other water tanks through which the water is sucked using a hydraulic pump in order to subject it to a given process and then send it towards the original tank or another. The electric motor of these pumps is built in such a way that certain parts of it such as the ceramic seal or the electric winding burn out if the motor continues operating without transferring water, such as when a duct is blocked, for example. The most common cause of this blockage is when a foreign object or even a human body obstructs the drain or discharge. These objects or persons causing the obstruction may be seriously harmed or damaged if the pump does not cease operation. In order to prevent such blockage and the subsequent damages, grilles or some other type of architectural barrier is placed over these inlets; due to faults in these barriers or negligent maintenance of the swimming-pool or tank, these damages cannot always be avoided. There are apparatus that shut down the pump operation in the event of blockage, thus eliminating the risk of damage to the pump, or to the object or person causing the blockage. These apparatus are based on the existence of a water pressure detector, preferably located in the suction area, which in the event of any variation in pressure or vacuum present in said area, transmits an electric signal to the pump and causes same to shut down. This detector device may comprise a manometer, which can be adjusted to shut down the pump or reduce its suction power by transmitting an electric signal to a relay operating the pump. Apparatus with this function are known, for example, in patent WO-A-9213195, in patent DE-A-4300560, and in patent US-A-4505643. The objective of patent WO-A-9213195 is a circuit for a pump which employs a safety device to switch off electrical power to the pump in the case where adverse pressure conditions are produced. The pump circuit includes a pump inlet conduit communicating with an inlet of the pump, an outlet conduit communicating with an outlet of the pump, a pump inlet pressure sensing line and a pump outlet pressure sensing line. The sensing lines are coupled to a power shut down control unit which is connected in series with the power supply to the pump through power lines. As long as the pressure upstream or downstream of the pump remains normal, power to the pump will be maintained by the control unit. Should the pressure sensed vary beyond predetermined limits, then power to the pump would be shut down by the control unit. The objective of patent DE-4300560 is a safety device for circulation pumps in boilers for heating water, which consists of temperature and pressure sensors located in the circulation pump suction piping, together with an analogue-digital converter circuit, that is connected to the sensors by conducting wires, with a micro-computer having inputs connected to the sensors, together with an output electrically connected to the analogue-digital converter. In this way, noise produced by cavitation, caused by the partial production of vapour if the water pressure is less than the water vapour pressure and when the pump is operating off-load sufficient feedwater enters the system circuit, is prevented and pump bearing deterioration is avoided. The objective of patent US-A-4505643 is a circulating pump which pumps water between a swimming pool or other reservoir and a filter or other circulated fluid receiving apparatus. A control circuit intermittently operates the circulating pump. The operating circuit includes a first timer and a cycle switch which is cyclically closed to produce a pump signal for a first duration with a first periodicity. The pump signal starts a second timer of a time controlled switch. The second timer holds the time controlled switch conductive for a preselected time period. The pump signal is conducted through a bypass switch, and the time actuated switch. When the pressure monitored by a pressure sensor exceeds a preselected pressure, a low pressure switch closes conducting the pump signal around the bypass and time controlled switches. A high pressure shutoff switch conducts the pump signal to a power relay coil unless a preselected high pressure is monitored. The power relay coil controls relay contacts through which electric power is supplied to a pump motor. Summary of the invention The apparatus described in this invention is equipped with at least one electric signal processing microcircuit, at least one manometer, at least one relay, at least one timer, luminous indicators, acoustic or visual alarms, a selector switch to disconnect and re-connect the apparatus and a subsystem to monitor re-start up. The electric signal processing microcircuit controls the flow of electric signals in accordance with a program designed for the characteristics of the water installation. The manometer is set so that, in the event of any variation in the pressure beyond a certain limit, it will transmit an electric signal to the microcircuit which, in accordance with the program to be executed, sends another signal to a relay to shut down the pump motor and put the timer into operation. The timer is programmable and has two functions. One is to cause the microcircuit to send a signal to the relay, after a programmed interval, to restart the pump. The other function is to disable the option of the microcircuit sending a stop signal to the relay due to low pressure, also during a programmable interval. This function is useful, as during the first moments when starting up the pump, there are short fluctuations in the pressure level in the circuit, due to the inertia of a liquid mass that is put into motion; the aim is to prevent any of these fluctuations beyond the permitted pressure limit, from causing the pump to shutdown. When the pump is restarted, the water pumping process will continue if the cause of the blockage has been removed. If such blockage should continue, the motor will shutdown again, and remain so during the programmed interval until the timer restarts it. If after the second or third interval the blockage persists, the system can be programmed so that the motor does not restart until manual intervention takes place. The luminous indicators will light up during normal operation of the relevant element, and when said element stops, the indicator will go out, and vice versa. The acoustic and/or visual alarms will activate when the pump motor shuts down. The selector switch allows the user to deactivate the system, so as to empty the swimming-pool, for example, and then re-activate it when the pool is full. As a safety measure, to deactivate the system requires holding the selector switch down for no less than three seconds. The restart monitoring subsystem controls all system elements and is intended to restore correct operation of each element before, or after, external anomalies, such as automatically restarting the system after a power-cut or de-blocking a blocked element, during a storm for example. These, and other features will become more apparent from the detailed description below, in addition to two drawings depicting a practical case, given solely as an example of the scope of this invention, not limited to same. Description of the drawings Figure 1 shows a layout of a swimming-pool in which this control apparatus is used, figure 2 shows the electrical diagram of all the safety elements, figure 3 shows a block diagram of the power source for this control apparatus, and figure 4 shows the diagram of the flow of electric signals within the apparatus. Practical case In accordance with the drawings, this control apparatus of pump 1 operation which sucks water A from swimming-pool P and impels it towards filter 2 for cleaning for subsequent return to the swimming-pool when clean, basically comprises the installation of a manometer 3 in water suction tube 4 of the swimming-pool via drain 5 whose mouth is usually protected with a grille. This manometer 3 is responsible for transmitting the electric signal to a safety-cabinet 6 where the first timer 7, a relay 8, a second timer 9 and a switch 10, whose safety-box will be connected to the relevant pump switchgear cabinet (not shown). This apparatus is designed so that in the event the manometer 3 interrupts pump 1 operation, the latter (or the set of pumps) will shut down for the time programmed on the first timer 7, after which time the pump will automatically resume operation for another, shorter time, programmed by the second timer 9. If the initial problem continues to exist, it will again shut down the pump, repeatedly, until the pump is shut down definitively. In said safety-cabinet 6, several luminous, "LED" type indicators in different colours are located, in order to specify the different operating conditions of the apparatus. Thus, for example, green will indicate current and operation; red, the timer action that stops the pump; yellow, second timer operation, and the fourth colour that the pressure switch-vacuum switch is open. Switch 10 will select connection or disconnection of the apparatus, for example for draining the swimming-pool with nobody present. The last component of the apparatus is the installation of independent alarms which will operate acoustic/visual signals to indicate any anomaly in the apparatus operation. Figure 3 shows the electric diagram of the power source represented in blocks, indicating 11, inlet of the 12, the manometer main safety timer, 13, the secondary timer, 14, the operating and signalling relays, 15, the indicator "LED's" and 16, the external connections. Should the hydraulic circuit lack a filter or any another element which could cause a variation in the pressure within said circuit, the manometer may be installed in any part of the circuit. In accordance with figure 4, when manometer records a pressure below the set value, it transmits an electric signal to microcircuit 17. On receiving the signal, the microcircuit sends a signal to relay 18 which cuts off the power supply to motor 19 of pump 1, thus shutting it down, and also sends a signal to timer 20 to commence count down of the time to elapse before the pump restarts. After the set time, timer 20 sends to microcircuit 17 the signal to operate the relay to start up motor 19 of pump 1, while at the same time blocking said microcircuit 17 so that during a time which can be set between 0 and 10 seconds, it should not respond to any low pressure signals received from manometer 3. If the cause of the drop in pressure disappears, the water pumping process continues in normal operation. If the cause should persist, manometer 3 will again record a pressure lower to that programmed, will again transmit a signal to microcircuit 17 which will again operate relay 18, stopping motor 19 of pump 1, and will start timer 21 (which depending on electronic technology could also be timer 20 itself). After another set time, the timer repeats the above function. If the cause of the drop in pressure disappears, the water pumping process continues in normal operation. If the cause should persist, manometer 3 will again record a pressure lower to that programmed, will again transmit a signal to microcircuit 17, and this will cause relay 18 to interrupt pump 1 operation. The timer will not start up the pump again. While the safety apparatus is activated, there will be a green light on 23, on the outside of assembly 22, which may be located inside a safety cabinet. If the apparatus is deactivated, the green light goes out and a red light 23' blinks. A lit yellow.light 23'' indicates that the pump is shut down. A blue light 23''' indicates that the manometer shows a pressure lower than programmed. A continuous red light 23 IV will light during the first few seconds when the pump is started up during which, due to the pressure fluctuation typical of the inertia of the fluid, microcircuit 17 does not send relay 18 the stop signal to the electric motor. Selector switch 24 enables to deactivate the apparatus and re-activate it. The monitoring subsystem 25 is responsible for restoring correct operation after anomalies due to external causes. In places visible from the swimming-pool or from an eventual control center, there shall be visual and/or acoustic alarms 23 V which will energise when the pump stops. In the flow diagram of the electric signals, manometer 3 sends its signal to the microcircuit of electric signals 17, which can send a signal to relay 18 to stop motor 19 of pump 1 and starts timer 20 or timer 21according to what has been envisaged or programmed. Signal leave the timer for microcircuit 17 which cause it to operate relay 18 while at the same time, during 10 seconds, they prevent any signals received from manometer 3 from being transformed in signals to relay 18. The conjunction of these devices is shown in reference 22 whose parts send the signals to pilot lights and alarms 23 to 23 V , or receive it from selector switch 24, or send them and receive them from the monitoring subsystem 25.

Claims: Apparatus for pump operation control which, in the area where the fluid is suctioned towards the pump (1), comprises a manometer (3) which, because of pressure variations or vacuum produced in this same area, transmits an electrical signal to a relay (8,18) controlling the pump (1) and stopping its operation, with the shutdown time programmed by a timer (7,12,20) characterised by the manometer (3), when the measured pressure exceeds a preset value, transmitting a signal to a microprocessor circuit (17), which in turn, produces two signals, one of which operates the relay (18) in order to stop the motor (19) of the hydraulic pump (1), whilst the other starts the programmable timer (12,20) operation which, once the motor (19) for the pump (1) has stopped and the programmed time has elapsed, transmits a signal to the electrical signal microprocessor circuit (17), the programmed time being between one minute and twelve hours. Apparatus, according to claim 1, characterised by the timer (12,20), after a programmed number of re-initialisations, each one of which indicating a period of pump (1) motor (19) operation of less than one minute, enters a phase during which the pump does not reinitialise pump (1) operation. Apparatus, according to claim 1, characterised by the timer (12,20), on re-initialisation of pump (1) operation, preventing during a maximum of ten seconds the microprocessor circuit (17) from transmitting the motor halt signal through relay (18) due to lack of pressure detected by manometer (3). Apparatus, according to claim 1, characterised by consisting in a selector switch (24), which enables or disables apparatus operation when being depressed continuously for a minimum of three seconds. Apparatus, according to claim 1, characterised by including a monitoring system (25) for re-initialisation of the apparatus, which uses the electrical signal microprocessor circuit (17), that receives signals from each apparatus components restarting automatically whatever components which may have been shut down for whatever reason, once this cause has disappeared, except where manual control or a loss of pressure have caused the stop.

Inventors: VILA CORTS FRANCESC XAVIER, VILA CORTS, FRANCESC XAVIER
Applicants: PLASTERAL SA, PLASTERAL, S.A.
Application year: 1998
Main classification: E04H4
IPC codes: E04H4