FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“SYSTEM AND METHOD TO AVOID DRY RUNNING OF
SUBMERSIBLE PUMP”
We, Bajaj Electricals Limited, an Indian National, of 45/47, Veer Nariman Road, Fort, Mumbai- 400001, Maharashtra, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention generally relates to the field of submersible pumps. In particular, the present invention relates to a system for safe operation of submersible pumps.
BACKGROUND OF THE INVENTION
This section is intended to provide information relating to the field of disclosure and thus, any approach or functionality described herein should not be assumed to qualify as prior art merely by its inclusion in this section.
Air coolers generally include a blower assembly including a set of blades disposed within an enclosure. The set of blades rotate to generate an air flow in a direction coaxial with the fan blades. Water cooled air coolers further include a water reservoir disposed within the enclosure or outside the enclosure. Tubes or pipes carry water from the water tank and through the enclosure. Water in the tubes exchange heat with air present within the enclosure, thereby cooling the air. The cooled air is pushed out by the set of blades to generate a cool draft of air.
Generally, water is pumped through the tubes or pipes using submersible pumps disposed in the water reservoirs. Conventional water-cooled air coolers do not possess a means to monitor a water level in the water reservoir in order to determine if the submersible pump may be safely operated. In instances where the water level is inadequate, operating the submersible pump may cause excessive heating of components of the submersible pump, potentially leading to their early failure.
There is, therefore, a requirement in the art, for an automatic means to determine if it is safe to operate the submersible pump in the water reservoir.
SUMMARY OF THE INVENTION
This section is intended to introduce one or more aspects and/or embodiments of the present disclosure in a simplified form and is not intended to identify any key advantages or features of the present disclosure.

In an aspect, the present invention provides a system to avoid dry running of a submersible pump, the system comprising: a control module comprising a continuity sensor disposed in a water reservoir, the continuity sensor comprising at least a first electrode, and at least a second electrode; a relay adapted to selectively electrically couple an external electric power source with the submersible pump; and a controller communicably coupled with the continuity sensor and the relay, wherein the controller is configured to: receive from the continuity sensor an electrical signal when at least a part of first electrode and at least a part of second electrode are in contact with water; and operate the relay in response to the received signal to selectively allow electrical power from the external electric power source to be supplied to the submersible pump.
In an aspect, at least a part of first electrode, and at least a part of second electrode, independently, is at a pre-determined height from a water-intake of the submersible pump.
In an aspect, the system further comprises at least an indicator configured to indicate a state of operation of the submersible pump, wherein the indicator is coupled to the controller.
In an aspect, the controller is configured on a printed circuit board (PCB).
In an aspect, the submersible pump is electrically coupled with the external electric power source via the relay when at least a part of first electrode and at least a part of second electrode are submerged in water.
In an aspect, the submersible pump is electrically de-coupled from the external electric power source via the relay when first electrode or second electrode is not in contact with water.
In an aspect, the operational range of the relay with regard to total dissolved solids (TDS) in the water is up to 3000.
In an aspect, the present invention provides a method to avoid dry running of a submersible pump, the method comprising: providing a system to avoid dry running of the submersible pump, the system comprising: a control module comprising a continuity sensor disposed in a water reservoir, the continuity sensor

comprising at least a first electrode, and at least a second electrode; a relay adapted to selectively electrically couple an external electric power source with the submersible pump; and a controller communicably coupled with the continuity sensor and the relay, wherein the controller is configured to: receive from the continuity sensor an electrical signal when at least a part of first electrode and at least a part of second electrode are in contact with water; and operate the relay in response to the received signal to selectively allow electrical power from the external electric power source to be supplied to the submersible pump; wherein when at least a part of first electrode and at least a part of second electrode are in contact with water, the submersible pump is electrically coupled with the external electric power source via the relay; or wherein when any of first electrode, second electrode or both is not in contact with water, the submersible pump is electrically decoupled with the external electric power source via the relay to avoid dry running of the submersible pump.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The present disclosure, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the description, taken in connection with the accompanying drawings. These and other details of the present invention will be described in connection with the accompanying drawings, which are furnished only by way of illustration and not in limitation of the scope of the present disclosure.
FIG. 1A illustrates a schematic block diagram of a system to avoid dry running a submersible pump, according to an embodiment of the present invention;
FIG. 1B illustrates a schematic perspective view of an integrated unit of a control module, a relay, and a controller of the system of FIG. 1A, according to an embodiment of the present invention; and
FIG. 2 illustrates a schematic flow diagram for a method to avoid dry running a submersible pump, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of one or more embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter may each be used independently of one another or in any combination with other features. An individual feature may not address any of the problems discussed above or may address only some of the problems discussed above. Some of the problems discussed above may not be fully addressed by any of the features described herein. Example embodiments of the present disclosure are described below, as illustrated in various drawings, in which same reference numerals refer to the same parts throughout the different drawings.
The present invention provides a system to avoid dry running of a submersible pump. In an embodiment, the submersible pump is immersed in a water reservoir of an air cooler. However, in other embodiments, the water reservoir may be part of any other apparatus. The system is configured to provide a limit to functioning of the submersible pump. Specifically, the system is configured to prevent operation of the submersible pump when the water level in the water reservoir is below a threshold level. Generally, when a submersible pump is operated at low water levels, components of the submersible pump may overheat, potentially leading to failure of the submersible pump. Therefore, by providing a restriction that the submersible pump may not operate when the water level in the reservoir is less than the threshold value, the system facilitates safe operation of the submersible pump, and potentially increases the operational lifetime of the submersible pump.
The system includes a control module including a continuity sensor disposed in the water reservoir. The continuity sensor includes at least a first electrode, and at least a second electrode. In an embodiment, At least the first and at least the second electrode are adapted to be electrochemically coupled when immersed in water. In an embodiment, at least a part of the first electrode, and at least a part of the second electrode, independently, is at a pre-determined height

from a water-intake of the submersible pump. The predetermined height may be indicative of a minimum height of water in the water reservoir that is required for the submersible pump to operate safely.
In an embodiment, the continuity sensor includes at least the first electrode and a plurality of second electrodes. In another embodiment, the continuity sensor includes a plurality of first sensors and at least the second electrode. In an embodiment, the continuity sensor includes a plurality of first and second electrodes. In a preferred embodiment, the continuity sensor is disposed proximate the water-intake of the submersible pump. In other words, the at least first electrode and the at least second electrode are disposed proximate the water-intake of the submersible pump.
In an embodiment, the first and second electrodes are made of materials selected from a group consisting of carbon, graphite, silver, gold, platinum, salts of silver, gold, platinum, and combinations thereof. In a preferred embodiment, the first and second electrodes may be made of materials that are cost-effective and have suitable chemical resistance to be used in water with high levels of dissolved salts so that the electrodes have a long operational lifetime. In an embodiment, the first and second electrodes are used in water with a total dissolved solids (TDS) value of up to 3000.
The system further includes a relay adapted to selectively electrically couple an external electric power source with the submersible pump. In an embodiment, the external electric power source is any one of an alternating current (AC) and a direct current (DC) source. In an embodiment, the external electric power source is a battery bank. In an embodiment, due to the use of high durability electrodes, the operational range of the relay with regard to TDS in the water is up to 3000.
The system further includes a controller communicably coupled with the continuity sensor and the relay. In a preferred embodiment, the controller is configured on a printed circuit board (PCB). In an embodiment, the controller is integrated with the relay, for example, to provision a smart relay. The controller may include a processor, and a memory communicably coupled to the processor. The memory may store instructions executable by the processor to cause the

processor to operate the relay. The controller is configured to receive, from the continuity sensor, an electrical signal when at least a part of first electrode and at least a part of second electrode are in contact with water. In other words, the electrical signal is indicative of the at least first and at least second electrodes being at least partially immersed in water in the water reservoir, thereby completing an electrochemical circuit with the water. The electrical signal is further indicative that there is sufficient water in the water reservoir for safe operation of the submersible pump.
The controller is further configured to operate the relay in response to the received signal to selectively allow electrical power from the external electric power source to be supplied to the submersible pump.
In an embodiment, the submersible pump is electrically coupled with the external electric power source via the relay when at least a part of first electrode and at least a part of second electrode are submerged in water. In other words, the submersible pump is electrically coupled with the external electric power source via the relay when the water in the water reservoir is at least at the pre-determined height.
In an embodiment, the submersible pump is electrically de-coupled from the external electric power source via the relay when first electrode or second electrode is not in contact with water. In other words, the submersible pump is electrically de¬coupled from the external electric power source via the relay when the water in the water reservoir is below the pre-determined height.
In an embodiment, the system further includes at least an indicator communicably coupled to the controller and configured to indicate a state of operation of the submersible pump. In an embodiment, the indicator is any one or a combination of a visual indicator, an audio indicator and a haptic indicator. In a preferred embodiment, the indicator is a combination of light emitting diodes (LEDs). The LEDs may be of different colours to indicate the different states of operation of the submersible pump. The LEDs may further indicate other information, such as availability of electrical current from the external electrical power supply and/or the state of the continuity sensor in the water reservoir.

FIG. 1A illustrates a schematic block diagram of a system 100 to avoid dry running a submersible pump 102, according to an embodiment of the present invention. The system 100 includes a control module 104. The control module 104 includes a continuity sensor 106 disposed in a water reservoir 108. In an embodiment, the water reservoir 108 is part of an air cooler (not shown in figure). The continuity sensor 106 includes first and second electrodes 110, 112. The continuity sensor 106 is positioned in the water reservoir 108 at a pre-determined height from a water-intake (not shown in figure) of the submersible pump 102. Specifically, the continuity sensor 106 is positioned, such that at least part of the first electrode 110, and at least part of the second electrode 112, independently, is at the pre-determined height from the water-intake of the submersible pump 102.
The system 100 includes a relay 114 adapted to selectively electrically couple an external electric power source 116 with the submersible pump 102. The system 100 further includes a controller 118 communicably coupled with the continuity sensor 106 and the relay 114.
In some embodiments, the control module 104, the relay 114, and the controller 118 is an integrated unit.
FIG. 1B illustrates a schematic perspective view of an integrated unit of the control module 104, the relay 114, and the controller 118, according to an embodiment of the present invention. The controller 118 is configured on a printed circuit board (PCB). In an embodiment, the integrated unit is potted. In other words, the integrated unit is made water resistant, such that the integrated unit can be immersed in the water reservoir. As a consequence, the integrated unit is adapted to function in water with high quantity of total dissolved solids (TDS). Specifically, the relay 114 is configured to operate in water having TDS of up to 3000.
Referring to FIGs. 1A and 1B, the controller 118 is configured to receive, from the continuity sensor 106, an electrical signal when at least a part of the first electrode 110 and at least a part of the second electrode 112 are in contact with water. The controller 118 is further configured to operate the relay 114 in response to the received signal to selectively allow electrical power from the external electric power source 116 to be supplied to the submersible pump 102. Specifically, wherein

the submersible pump 102 is electrically coupled with the external electric power source 116 via the relay 114 when at least a part of first electrode 110 and at least a part of second electrode 112 are submerged in water. Further, the submersible pump 102 is electrically de-coupled from the external electric power source 116 via the relay 114 when first electrode 110 or second electrode 112 is not in contact with water.
Further, the system 100 includes an indicator 120 communicably coupled to the controller 118. The indicator 120 is configured to indicate a state of operation of the submersible pump 102.
FIG. 2 illustrates a schematic flow diagram for a method 200 to avoid dry running the submersible pump 102, according to an embodiment of the present invention. Referring to FIGs. 1A to 2, at step 202, the method 200 includes providing the system 100 to avoid dry running of the submersible pump 102. At step 204, the method 200 includes electrically coupling the submersible pump 102 with the external electric power source 116 via the relay 114 when at least a part of first electrode 110 and at least a part of second electrode 112 are submerged in water. Alternately, at step 206, the method 200 includes electrically de-coupling the submersible pump 102 from the external electric power source 116 via the relay 114 when first electrode 110 or second electrode 112 is not in contact with water.
Thus, the system 100 and method 200 of the present invention provide for prevention of dry running of the submersible pump 102. The control module 104 is configured to detect, based on immersion of first and second electrodes 110, 112 in water at the pre-determined height in the water reservoir 108, presence of water at the pre-determined height in the water reservoir 108. In the presence of adequate quantity of water, the relay 114 is configured to allow supply of electric power to the submersible pump 102 to operate the submersible pump 102. In the absence of adequate quantity of water in the water reservoir 108, the relay 114 is configured to disallow supply of electric power to the submersible pump 102. As a result, operation of the submersible pump 102 at low water quantity, or dry running of the submersible pump 102 is prevented, thereby improving health of the submersible pump 102 and maintaining its operating lifetime. Furthermore, the control module

104 along with the relay 114 and controller 118 are configured in an integrated unit that is configured to be submersible and is suitably chemically resistant to water having TDS of up to 3000.
While the preferred embodiments of the present disclosure have been described hereinabove, it may be appreciated that various changes, adaptations, and modifications may be made therein without departing from the spirit of the disclosure and the scope of the appended claims. It will be obvious to a person skilled in the art that the present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments may to be considered in all respects only as illustrative and not restrictive.
LIST OF REFERENCE NUMERALS
100 System
102 Submersible Pump
104 Control Module
106 Continuity Sensor
108 Water Reservoir
110 First Electrode
112 Second Electrode
114 Relay
116 External Electric Power Source
118 Controller
120 Indicator
200 Method
202 Step
204 Step
206 Step

I/We Claim:
1. A system (100) to avoid dry running of a submersible pump (102), the
system (100) comprising:
a control module (104) comprising a continuity sensor (106) disposed in a water reservoir (108), the continuity sensor (106) comprising at least a first electrode (110), and at least a second electrode (112);
a relay (114) adapted to selectively electrically couple an external electric power source (116) with the submersible pump (102); and
a controller (118) communicably coupled with the continuity sensor (106) and the relay (114), wherein the controller (118) is configured to:
receive from the continuity sensor (106) an electrical signal when
at least a part of first electrode (110) and at least a part of second
electrode (112) are in contact with water; and
operate the relay (114) in response to the received signal to
selectively allow electrical power from the external electric power
source (116) to be supplied to the submersible pump (102).
2. The system (100) as claimed in claim 1, wherein at least a part of first electrode (110), and at least a part of second electrode (112), independently, is at a pre-determined height from a water-intake of the submersible pump (102).
3. The system (100) as claimed in claim 1, further comprising at least an indicator (120) configured to indicate a state of operation of the submersible pump (102), wherein the indicator (120) is coupled to the controller (118).
4. The system (100) as claimed in claim 1, wherein the controller (118) is configured on a printed circuit board (PCB).

5. The system (100) as claimed in claim 1, wherein the submersible pump (102) is electrically coupled with the external electric power source (116) via the relay (114) when at least a part of first electrode (110) and at least a part of second electrode (112) are submerged in water.
6. The system (100) as claimed in claim 1, wherein the submersible pump (102) is electrically de-coupled from the external electric power source (116) via the relay (114) when first electrode (110) or second electrode (112) is not in contact with water.
7. The system (100) as claimed in claim 1, wherein the operational range of the relay (114) with regard to total dissolved solids (TDS)in the water is up to 3000.
8. A method (200) to avoid dry running of a submersible pump (102), the method (200) comprising:
providing a system (100) to avoid dry running of the submersible pump (102) as claimed in claim 1,
wherein when at least a part of first electrode (110) and at least a part of second electrode (112) are in contact with water, the submersible pump (102) is electrically coupled with the external electric power source (116) via the relay (114); or wherein when any of first electrode (110), second electrode (112) or both is not in contact with water, the submersible pump (102) is electrically decoupled with the external electric power source (116) via the relay (114) to avoid dry running of the submersible pump (102).