FORM 2THE PATENT ACT 1970(39 OF 1970)&The Patent Rules, 2003
COMPLETE SPECIFICATION (See Section 10 and Rule 13)
1 TITLE OF THE INVENTION :
SYSTEM FOR COOLING HYDRAULIC OIL IN EXCAVATORS
2 APPLICANT (S)
Name : STEEL AUTHORITY OF INDIA LIMITED
Nationality : A Govt, of India Enterprise
Address : Bhilai Steel Plant, Bhilai, State of Chattisgarh, India
3 PREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is tobe performed.

FIELD OF THE INVENTION:
The present invention is directed to a system for cooling hydraulic oil in an
excavator to .achieve improved performance and reliability by means of improving cooling efficiency with enhanced life of the hydraulic system avoiding overheating of oil. The system of the invention would favor eliminating some typical problems experienced in the operation/maintenance and performance of the excavator equipment due to overheating of oil. The hydraulic excavator is extensively used as earth moving equipment in various industrial applications including material handling/excavating/cleaning or loading/unloading in its day to day operation in heavy endustries/constructions such as in large steel plants where it is widely used for cleaning of pit in SMS, handling of slag or coal etc in respective plants. The present system of the invention is directed to the advantageous selective vertical disposition of mounting of the oil cooler of excavator and the connecting inlet and outlet pipe lines to suit such modification and the selective disposition of cooling fan adapted for better cooler orientation such that the problem of overheating of oil caused due to chocking of ventilating passages of the air cooled equipment in dusty work atmosphere because of its existing horizontal position leading to dust and foreign particle accumulation on cooling/heat exchange surfaces, is eliminated. Moreover, the problems associated with malfunctioning/failure of auxiliary equipments like hydraulic cylinders, pumps, motors in the conventional system with hydraulic oil being used at high temperature due to low oil viscosity have also been eliminated in the oil cooler system of the present invention. The efficient cooling effect of the hydraulic oil was also achieved by directing the unobstructed flow of cooling air from fan through the oil cooler, horizontally into the atmosphere. The vertical mounting of cooler also facilitate the visual check for cooling fan operation and easier access to the oil cooling system for regular maintenance/cleaning work. Thus the present invention is having immense importance in operating and
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maintaining hydraulic oil cooling systems for essential earth moving equipments like the excavators in vital industry segments with improved efficiency and economy.
BACKGROUND AND PRIOR ART:
Hydraulically operated excavators are essential equipments for excavation, material handling of different nature in wide range of heavy industry segments, including the steel plants. Particularly, in steel plants the excavators are essential earth moving equipment used with advantage in bulk material handling, cleaning, loading/unloading of coal or slag in various sections like SMS, MRD, MCHP or CPP (kindly give the full forms of abbreviations used with details of use of excavator handling capacity/volume in a shift/day) to lay importance etc. to facilitate smooth plant operations without any bottleneck. The excavators are thus important supporting equipments in the steel plant operations. The actuation of various functional movements of the excavators are achieved by hydraulic oil systems by means of pumps, motors, hydraulic cylinders and their interconnections etc and the effective functioning of such elements in combination ensure reliable performance of the excavator. The hydraulic oil being used to activate the functions of the excavator at the shop floor/site is therefore subjected to rise in temperature in normal operations and need to be cleaned and cooled or maintained at safe temperature limits to ensure reliable performance of the system. In the conventional application, the hydraulic oil used in the excavator is cooled by air cooling by means of air flow created by a fan in vertical direction through said cooler placed horizontally. But due to the presence of dust, dry leaves or other flying foreign materials, usually prevailing at shopfloor/work sites' atmosphere, deposit on the said horizontal oil cooler in the existing set up having large exposed horizontal surface area and the passages for air flow provided in the cooler for effective heat exchange gets chocked and hinder to achieve desired cooling effect of the hydraulic oil. As a result of this the oil at higher than normal temperature is being used in the system affecting the performance of the control valves, hydraulic pump and
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motor, hydraulic cylinders due to worm oil with low viscosity. Thus the performance of excavator is also affected needing frequent cleaning of cooler located at inconvenient place and difficult maintenance activity. It was therefore the persistent need in the use of excavators in shop floor particularly in hot and dusty environment such as in different sections of large steel plants, that the hydraulic oil cooler be provided to cool the oil to desired temperature to ensure efficient performance of the hydraulic system and its auxiliaries so that the excavator may be operated reliably without or reduced failure/break down and with easier maintainability, in adverse work environment.
OBJECTS OF THE INVENTION:
It is therefore the basic object of the present invention to provide a system for cooling of hydraulic oil in excavators and the like so as to avoid problems of chocking and pollution and achieve desired cooling of the oil at desired temperature avoiding overheating, with better efficiency in performance, reliability and ease of maintenance.
A further object of the present invention is directed to reorient the conventional horizontal position of the oil cooler in excavators into vertical position, for improved heat exchange efficiency in order to avoid choking of the cooler due to dust/foreign particle deposition on the horizontal cooler/heat exchange surface.
A further object of the present invention is directed to orient the fan cooler of said air cooled oil cooler such that the air is discharged horizontally to atmosphere, favouring visual checking of fan operation and easy access for routine maintenance/cleaning.
A still further object of the present invention is to achieve the effective functioning of hydraulic oil systems of the excavators comprising of pumps, motors, hydraulic cylinders and their interconnections etc., by maintaining
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proper operating temperature of hydraulic oil and such elements in combination ensure reliable performance of the excavator.
A further object of the present invention is directed to facilitate cleaning of the cooler in case of choking of cooler when working in dusty shop floor atmosphere due to deposition of dust and other foreign materials.
SUMMARY OF THE INVENTION:
Thus according to the basic aspect of the present invention there is provided a system for cooling hydraulic oil in excavators comprising:
hydraulic oil cooler disposed vertically with the fan selectively positioned and adapted such that the air used for cooling of the hydraulic oil comes out through the cowling to the atmosphere free of any problems of chocking of the cooler.
Importantly, in the above system for cooling hydraulic oil in excavators of the invention the system comprises selectively positioning the oil supply and return line with respect to the cooler fan disposed vertically.
The system for cooling hydraulic oil in excavators is further directed to adapting the selective disposition with respect to the oil line to eliminate oil cooler chocking problem and over heating of the oil.
The cooling fan is also selectively disposed such that the operative status of the fan can be easily viewed from outside.
In particular, the system involves selectively disposing the cooler fan vertically and providing corresponding directional supply and return path for the oil pipeline for the choke and dust free operation of the cooler unit.
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In accordance with another aspect of the invention there is thus disclosed an excavator incorporating the system for cooling hydraulic oil as above.
In keeping with the above basic aspect the present invention is therefore directed to provide an efficient hydraulic oil cooling system to avoid overheating of oil maintaining desired operating temperature, for excavators used in dusty shop floor/work sites, such as in different sections of steel plants*
Importantly, the air cooled oil cooler for the hydraulic system is placed in preferred vertical position to ensure proper heat-exchange to maintain desired temperature and viscosity of hydraulic oil used in said system. The system would favour maintaining the temperature of hydraulic oil in allowable ranges and facilitate proper functioning of the hydraulic cylinders, pump, motor, control valves used in the system, to achieve efficient performance of said oil cooler.
The fan cooler providing air cooling means of said hydraulic oil cooler is also located in preferred vertical orientation to favour horizontal uninterrupted air discharge in atmosphere from said oil cooler through ventilation provided on the cowling, avoiding choking by dust/foreign materials;
A further aspect of the present invention is to maintain orientation of inlet and outlet oil pipe line connection to suit said preferred vertical position of oil cooler.
A further aspect of the present invention is to facilitate easier and faster maintenance/cleaning of the cooler in case of choking of cooler when working in dusty shop floor atmosphere due to deposition of dust and other foreign materials.
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A further aspect of the present invention is directed to advantageous structural modification to facilitate said vertical mounting of the air cooled oil cooler and its fan and incoming and outlet oil pipe line connections with said cooler and the oil reservoir through the hydraulic system of the excavator, by application of cutting and welding means for the required supporting members.
The present invention and its objects and advantages are described in greater details with reference to the following accompanying figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES:
Figure 1: is an illustration of the conventional horizontal type oil cooler of the
excavator causing overheating of oil.
Figure 2: is the illustration of an improved hydraulic oil cooling system according
to present invention for use in excavators avoiding overheating of oil.
Figure 3: is the illustration of the side ventilation (V) on the cowling of the
excavators.
DETAILED DESCRIPTION WITH REFERENCE TO ACCOMPANYING
FIGURES:
Reference is first invited to the accompanying Figure 1 which illustrates the oil cooler in a conventional hydraulic oil cooling system in excavators. The oil cooler is having a horizontal position with outlet and inlet pipe connections for supply and incoming oil from the hydraulic system of the excavator to the cooler and cooled oil to the oil reservoir, respectively. The conventional oil coolers make use of air cooling by providing air flow from a fan driven by a motor mounted at the bottom side of the horizontally placed oil cooler such that the air flows out of the cooler in upward direction. Due to such position of the oil cooler, the dust , dry leaves or other foreign materials in the shop/site environment are free to deposit on the large horizontal surface of the cooler. As a result of this the passage of air through the oil cooler gets choked causing rise in temperature of oil at outlet of cooler is above the permissible limit that adversely affect the operation of the various elements of the cooler e.g. hydraulic cylinders, motor,
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pump, control valves and the interconnections. Such conventional hydraulic system operating with overheated/worm oil having lower viscosity at such elevated temperature subjects the elements of the system to frequent breakdown and due to the location disadvantage of the horizontal cooler inspection of fan operation or routine maintenance/cleaning of the oil cooler is difficult, inconvenient to access and also time consuming. The excavators being the important mode of material handling, for loading/unloading and also as heavy earth moving equipment in various industries and more particularly various sections of large integrated steel plantse.g. pit cleaning in SMS, loading of slag in MRD and coal handling in MCHP and CPP etc. Thus the down time experienced for such vital equipment due to overheating of oil may jeopardize the operations and/or production loss. Thus the hydraulic oil cooling system is required to provide reliability in performance of excavators avoiding overheating of oil and ensure ease of maintenance of oil coolers.
Figure 2 illustrates the improved hydraulic oil cooling system of the excavators according to the present invention. The oil cooler of the present system is advantageously mounted in vertical position (VNP) by incorporating some structural modifications deploying gas cutting and welding of the supports for the cooler and accessories. The inlet (INC) and outlet (OTC) connection pipes for conveying the hydraulic oil (OL) is modified in the present cooling system to favor matching with the vertical orientation of the oil cooler and necessary structural supports are provided for such modification.
The air cooling fan with motor is mounted to favor horizontal flow of air at the back side of the cooler; thus avoiding choking due to dust or foreign materials deposition on the heat exchanging surface of the oil cooler while working in open adverse environment and blocking air passage through the cooler and thereby facilitating effective desired cooling of the hydraulic oil during sustained use of excavators.
Figure 3 is the illustration of the oil cooler according to the present invention wherein the view of the side ventilation (V) on the cowling of the excavator
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enabling smooth flow of air from cooling fan through the passages in between the heat exchanging surfaces of said oil cooler. Also the position of fan in the air cooled oil cooler of the present invention provides means for sucking in cold air from free space as compared to the position in conventionally at the bottom of the oil cooler. Moreover, the said location of the fan also facilitate visual checking of its functioning/running without any difficulty.
The present system of hydraulic oil cooling in the excavator is thus able to provide cooling means for the hydraulic oil at an operatively safe temperature limit by way of avoiding problems of chocking of coolers and resultant rise in oil temperature beyond desired ranges in a reliable manner such that the all the elements of the oil cooler function efficiently minimizing breakdown of the excavator due to overheating of oil and its consequent effect on the vital components.
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WE CLAIM:
1. A system for cooling hydraulic oil in excavators comprising:
hydraulic oil cooler disposed vertically with the fan selectively positioned and adapted such that the air used for cooling of the hydraulic oil comes out through the cowling to the atmosphere free of any problems of chocking of the cooler.
2. A system for cooling hydraulic oil in excavators as claimed in claim 1
comprising selectively positioning the oil supply and return line with respect to
the cooler fan disposed vertically.
3. A system for cooling hydraulic oil in excavators as claimed in anyone of claims 1 or 2 comprising adapting the selective disposition with respect to the oil line to eliminate oil cooler chocking problem and over heating of the oil.
4. A system for cooling hydraulic oil in excavators as claimed in anyone of claims 1 to 3 selectively disposing the cooling fan such that the operative status of the fan can be easily viewed from outside.
5. A system for cooling hydraulic oil in excavators as claimed in anyone of claims 1 to 4 comprising selectively disposing the cooler fan vertically and providing corresponding directional supply and return path for the oil pipeline for the choke and dust free operation of the cooler unit.
6.An excavator incorporating the system for cooling hydraulic oil as claimed in anyone of claims 1 to 5.
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7. A system for cooling hydraulic oil in excavators and an excavator incorporating such system substantially as herein described and illustrated with reference to the accompanying figures.

Dated this 8th day of February, 2007. Anjan Sen
Of Anjan Sen & Associates (Applicants Agent)
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ABSTRACT
SYSTEM FOR COOLING HYDRAULIC OIL IN EXCAVATORS.
A system for cooling hydraulic oil in excavators to achieve improved performance and reliability by improving cooling efficiency of the hydraulic system avoiding overheating of oil. The present invention is directed to the advantageous selective vertical disposition of the oil cooler of excavator and the connecting inlet and outlet pipe lines to suit such modification and the selective disposition of cooling fan adapted for better cooler orientation avoiding overheating of oil caused due to chocking of ventilating passages. The oil cooler in dusty work atmosphere, work satisfactorily avoiding dust and foreign particle accumulation on cooling/heat exchange surfaces. The problems of malfunctioning/failure of auxiliary equipments like hydraulic cylinders, pumps, motors etc with hydraulic oil being used at high temperature and low oil viscosity have also been eliminated. The unobstructed flow of cooling air from fan through the oil cooler, thrown horizontally into the atmosphere through cowling. The vertical mounting of cooler also facilitate the visual check for cooling fan operation and regular maintenance/cleaning.
Figure 2.
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