Claims:1. A system (100) for testing the performance of an oil cooler, the system (100) comprising:
an oil circuit (101) including an oil storage tank (102) with a heating element (103), an oil filtration system (104), an oil pumping and re-circulation system (105), a temperature and pressure controlling system (106); and
a water circuit (107) including a water storage tank (108), a water pumping and re-circulation system (109), a water filtration system (110), a temperature and pressure controlling system (111, TG);
wherein, the cooler (200) is having two concentric tubes in contact with each other, separating the two mediums i.e oil on outer side and water on inner side for cooling of the oil;
wherein temperature of hot oil at oil inlet (112) and cold oil at oil outlet (113) is measured and difference between the temperature of hot oil and cold oil determines the performance of the oil cooler (200).
2. The system as claimed in claim 1, the heating system (103) uniformly heats the oil in the range of 85-90oC.
3. The system as claimed in the claims 1-2, wherein a oil filter (104) (duplex tube), pressure control valves (P), flow control valves, flow meter, pressure gauge, throttle valve (T) and temperature digital indicators are provided in the oil circuit.
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4. The system as claimed in the claims 1-3, wherein measurement of temperature is carried out by a Resistance Temperature Detector (RTD) at both oil inlet (112) and oil outlet (113) together with a temperature controller/thermostat.
5. The system as claimed in the claims 1-4, wherein a water filter (110) (duplex type), control valve, flow meter, pressure gauge and temperature gauge are provided in the water circuit.
6. The system as claimed in the claims 1-5, wherein a control panel (P) is provided to control the oil circuit (101) and water circuit (107).
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7. The system as claimed in the claims 1-6, comprises an alarm system (117) to be triggered in case oil temperature exceeds 90°C.
8. The system as claimed in the claims 1-7, wherein the pipeline of oil and water is a combination of rigid and flexible piping. , Description:SYSTEM FOR TESTING PERFORMANCE OF TRANSFORMER COOLERS
FIELD OF THE INVENTION
[001] The present disclosure, in general, relates to a system for testing the performance of transformer oil coolers. More particularly, the present invention relates to a testing system for testing the performance of double tube OFWF coolers used for cooling of oil in transformers.
BACKGROUND OF THE INVENTION
[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] In the usual designs of transformers, oil is cooled by circulating the hot oil at high temperature using Double tube OFWF (oil forced water forced) coolers.
[004] In present times, the available testing technology is limited to testing of mechanical pressure also known as mechanical pressure tests which is carried out during the manufacturing stages and includes testing of pressure on both tube side and shell side during the process of manufacturing. Such type of tests is used to ensure quality of tube expansion joints, welding joints and other manufacturing defects. These tests are conducted using systems which have a limited functionality and can only perform during the stages of manufacturing.
[005] In the current scenario, there is no such testing system available for measuring the cooling performance of coolers before their dispatch due to non-availability of any such testing setup or system. In other words, there is no concept of testing performance of a cooler before its dispatch in the usual procedures.
[006] In the absence of any performance test post manufacturing stage, if any performance related issue is reported on-site, the same has to be addressed on an urgent basis and this involves deployment of man power on site to work in adverse situations where there is lack of resources and space.
[007] Since, there is no provision for checking the performance of a double tube cooler in post manufacturing stage, there is a requirement to test the performance of a double tube OFWF cooler under actual working parameters and further checking the resulting performance.
[008] In the view of the above-cited issues, there is a need for a novel system to check the temperature difference of an inlet and outlet of oil cooler under actual working conditions.
[009] Accordingly, a system has been devised that can overcome one or more limitations stated above or any other limitation associated with the prior arts.
OBJECTS OF THE INVENTION
[010] It is a general object of the present disclosure to develop a testing system or set-up for testing the performance of OFWF coolers, which overcomes disadvantage of the prior art(s).
[011] It is an object of the present disclosure to provide for the testing system to perform the test under actual working conditions during the dispatch stage.
[012] It is an object of the present disclosure to provide for safety, environment friendliness, precise and controlled measurements and minimum space requirements in relation to the present invention.
[013] Another object of the present invention is to provide system for testing performance of transformer coolers which is simple in construction.
[014] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION
[015] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.
[016] According to this invention, there is provided a system for testing the performance of an oil cooler, the system comprising:
an oil circuit including an oil storage tank with a heating element, an oil filtration system, an oil pumping and re-circulation system, a temperature and pressure controlling system; and
a water circuit including a water storage tank, a water pumping and re-circulation system, a water filtration system, a temperature and pressure controlling system;
wherein, the cooler is having two concentric tubes in contact with each other, separating the two mediums i.e oil on outer side and water on inner side for cooling of the oil.
wherein temperature of hot oil at oil inlet and cold oil at oil outlet is measured and difference between the temperature of hot oil and cold oil determines the performance of the oil cooler.
[017] The heating system uniformly heats the oil in the range of 85-90oC.
[018] A oil filter, pressure control valves, flow control valves, flow meter, pressure gauge, throttle valve and temperature digital indicators are provided in the oil circuit.
[019] Measurement of temperature is carried out by a Resistance Temperature Detector (RTD) at both oil inlet and oil outlet together with a temperature controller/thermostat.
[020] A water filter, control valve, flow meter, pressure gauge and temperature gauge are provided in the water circuit.
[021] A control panel is provided to control the oil circuit and water circuit.
[022] An alarm system to be triggered in case oil temperature exceeds 90°C.
[023] The pipeline of oil and water is a combination of rigid and flexible piping.
[024] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
[025] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[026] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[027] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein: -
Fig. 1 illustrates a schematic arrangement of a performance test set-up or system (100) with oil or water storage tanks including control and flow measurement equipment in accordance with an embodiment of the present disclosure.
[028] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF PREFERRED EMBODIMENTS
[029] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[030] Embodiments explained herein pertaining to the present invention are directed towards providing a system for testing the performance of oil coolers i.e. OFWF coolers used in transformers.
[031] In OFWF cooling system of transformer, the hot oil is supplied to an oil to water heat exchanger by means of oil pump and there the oil is cooled by applying sowers of cold water on the heat exchanger’s oil pipes. OFWF refers to “Oil Forced Water Forced” cooling in transformer.
[032] Now, reference may be made to FIG. 1 illustrating a schematic arrangement of a performance test set-up with oil or water storage tanks including control and flow measurement equipment in accordance with an embodiment of the present invention.
[033] Disclosed herein and as shown in Figure 1, the system (100) comprises of an oil circuit (101) comprising an oil storage tank (102) with a heating element (103), an oil filtration system (104), an oil pumping and re-circulation system (105) with flow, a temperature and pressure controlling system (106) and a water circuit (107) comprising a water storage tank (108), a water pumping and re-circulation system (109), a water filtration system (110), a temperature and pressure controlling system (111, TG) wherein temperature of hot oil at oil inlet (112) and cold oil at oil outlet (113) is measured and difference between the temperature of hot oil and cold oil is calculated for determining the performance of an oil cooler.
[034] The oil in the tank (102) is heated electrically or using a suitable heating system (103) up to maximum temperature of 85°C to 90°C. Initially, the oil in tank (102) is at ambient temperature. In an example, the flash point of transformer oil is 140°C.

[035] Suitable Resistance Temperature Detectors (RTDs) for temperature measurement at oil inlet (112) and oil outlet (113) of the tank with a suitable temperature controller (106) or thermostat are integrally provided to control the temperature of oil. A suitable oil filter (104) (duplex type), pressure control valves (P), flow control valves, flow meter, pressure gauge, throttle valve (T) and temperature digital indicators are provided in the oil circuit.
[036] A suitable oil pump (109) is provided with the required pumping pressure. The heated oil enters from the inlet (112) of the cooler (200) and after cooling, the cold oil exits from the outlet (113) of the cooler. The cold oil is then re-circulated into oil tank (102). A reflex & transparent type of low and high level indicator for the oil is provided in the oil tank. The tank capacity is such that it can accommodate the expanded volume of oil and fumes formed during heating. A vent (V) or a chimney on the top of tank is provided for exit of gases and fumes generated during heating of oil. A valve (L) at the bottom of oil tank is provided for oil drainage.
[037] The raw water is stored at ambient temperature in the water tank (108). Suitable water filter (110) (duplex type), control valve, flow meter, pressure gauge and temperature gauge are provided in the water circuit. Further, a suitable water pump (109) is provided. The cold water enters from the water inlet (114) of the cooler and finally hot water comes out through water outlet (115) of cooler to be drained out. A reflex & transparent type of low and high level indicator for water is provided in the water tank.
[038] The oil cooler is double tube cooler, which is having provision for flow of water and oil separately. Here, the cooler is having two concentric tubes, wherein the tubes share a common wall as shown. According to the invention, oil flows through the outer tube and water flows through the inner tube. This flow arrangement causes cooling of hot oil with the help of cold water. However, the water gets heated up gradually with time. Therefore, the hot water is drained out through outlet (115) as per requirement i.e. when it exceeds the allowable temperature, which is indicated in Temperature gauge (TG) provided in proximity to water inlet (114) in the pipeline.
[039] Further, there is provision of control panel (P), which controls the oil circuit as well as water circuit.

[040] Thus the temperature of hot oil at the oil inlet (112) and cold oil at the oil outlet (113) of cooler is measured and the difference between the two temperatures of oil is calculated to check the performance of the oil cooler.
[041] Since the sizes of coolers varies, the Pipeline of oil and water is in a combination of rigid and flexible piping. The flexible piping along with reducers is provided.
[042] The problem of overflow of oil into oil tank (102) and the overflow of water into water tank (108) is overcome by using control valve (116)/ non-returnable valve (116) / suitable arrangements (116).
[043] Further, the heating system (103) is designed in such a way that uniform heating of the oil is achieved and localized heating of oil is prevented. An alarm system (117) is integrated to give an alarm in case heating of oil takes place beyond allowable temperature i.e. 90 °C leading to overheating.
[044] The testing set up or system (100) and circuit (101,107) is designed in such a manner that it occupies minimum space. The complete testing system (100) includes the following main parts: -
Oil Storage Tank
Water Storage Tank
Heating coil (heater)
Temperature control unit and thermostat
Duplex type oil filter
Duplex type water filter
Control valves for oil & water
Oil Transfer pump
Pressure gauges
Pressure relief valve
Temperature gauge
Pipe connection
Oil & Water Flow meter
Control Panel and control desk
Oil Storage Tank (102)
[045] The transformer oil in the tank is heated electrically or using a suitable heating system up to maximum temperature of 80°C to 90°C. Initially, oil in tank is at ambient temperature. The flash point of transformer oil is 140°C. Suitable Resistance Temperature Detectors (RTDs) for temperature measurement at oil inlet (112) and oil outlet (113) of the tank with a suitable temperature controller/ thermostat is integrated to control the temperature of oil.
[046] A suitable oil filter being a duplex type filter, pressure control valves, flow control valves (116), oil flow meter, pressure gauge and temperature digital indicators, etc. is incorporated in the circuit. Agitator facilities is provided in the tank for proper mixing of hot & cold oil. Since the size of oil cooler varies, the discharge of oil pump varies for example: from 255 LPM to 2250 LPM. A heat resistant oil pump having maximum discharge capacity of for example: 2250 LPM is provided with control valve to control the flow rate of oil.
[047] The pump needs to overcome the maximum limit of pressure drop in the oil flow circuit. The heated oil enters from the inlet of the cooler and after cooling the cold oil exits from the outlet of the cooler. The cold oil is then re-circulated into oil tank (102).
[048] A reflex & transparent type of low and high level indicator for oil is provided in the oil tank (102). Tank capacity should be such that it can accommodate the expanded volume of oil and fumes formed during heating. A vent or a chimney on the top of oil tank (102) is provided for exit of gases and fumes generated during heating of oil. A valve at the bottom of oil tank is provided for oil drainage.
Water Storage Tank (108)
[049] The raw water is stored at ambient temperature in the water tank (108). A suitable water Y-Type Strainer, pressure control valves, flow control valves, water flow meter, pressure gauge and temperature digital indicators, etc. are incorporated in the water circuit (107). Since, the size of oil cooler varies, the discharge of water pump varies for example: from 500 LPM to 1000 LPM. A suitable water pump having required discharge capacity of 1000 LPM is provided with suitable control valve to control the flow rate of water. The pump needs to overcome the maximum pressure drop in the water flow circuit (107).
[050] The cold water enters from the water inlet (114) of the cooler and finally hot water comes out through the water outlet (115) of cooler and is drained out. A reflex & transparent type of low and high level indicator for water is provided in the water tank (108). Eventually, the temperature of hot oil at the oil inlet (112) and cold oil at the oil outlet (113) of cooler is measured and the difference between the two temperatures of oil is calculated to check the performance of the oil cooler.
[051] The performance testing of oil cooler is carried out by a system principally claimed in claim 1, wherein subsequent claims depict its subsidiary features.
Reference Numerals
Numeral Description
100 Testing system
101 Oil circuit
102 Oil storage tank
103 heating element
104 oil filtration system
105 oil pumping and re-circulation system
106 temperature and pressure controlling system
107 water circuit
108 water storage tank
109 water pumping and re-circulation system
110 water filtration system
111 Water temperature and pressure controlling system
112 oil inlet
113 oil outlet
114 Water inlet
115 Water outlet
116 Control valve / non-returnable valve
117 alarm
V Vent
T Throttle valve
P Pressure control valves
L Oil drain
200 Oil cooler

[052] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[053] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[054] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[055] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[056] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[057] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[058] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.