F O R M - 2
THE PATENTS ACT, 1970 (39 OF 1970)
& The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. Title Of the Invention : AN IMPROVED BEARING HOUSING WITH ENHANCED COOLING
SYSTEM.
2. Applicant(s)
Name, Nationality & Address: KSB Tech Pvt. Ltd.
Godrej Castlemaine, 2nd Floor,
Bund Garden Road,
Pune-411001.
An Indian Company
3. Preamble to the description :
COMPLETE : The following specification particularly describes the
invention and the manner in which it is to be performed.

FIELD OF INVENTION:
The present invention relates to an improved bearing housing with enhanced cooling system.
BACKGROUND OF THE INVENTION:
All rotors are supported on bearings which are located in a bearing housing. Forces seen by a rotor are transmitted through the bearings to the bearing housing, thence to the structure on which the bearing housing is mounted or connected. Bearing are subjected to forces acting in both radial and / or axial direction relative to the axis of rotation.
Bearings are either of antifriction type or of plain bearing type. Anti friction .'
bearing systems are self contained simpler units but they have much reduced load carrying capacity at higher speeds compared to plain bearings. (The term load is used to represent the forces transmitted through a bearing). Plain bearings require external lubricating oil system. While, antifriction bearing can do without such an external lubricating system.
The loading limit at every speed is recommended to realise a high probability of trouble free operation for an acceptable duration of service. Such limitation arises from the maximum permissible temperature within the bearing arising out of friction between parts with relative motion. The lubricant serves to reduce the friction

coefficient and carry away the generated heat. Antifriction bearings are very partially dipped in an oil sump and have limited scope of lubricating oil flow between the bearing elements. Therefore the attempt is to cool the oil in the sump of the bearing housing, and the housing itself as much as possible. Improved cooling of oil and therefore the bearing will be able to carry higher than normal load or enhance its life expectancy under normal load limits. However, it is also necessary to ensure that the effectiveness of cooling leads to cooler oil coming into the bearing. Otherwise, cooler oil will settle at the bottom and warmer oil remains at the top where the bearing is dipping.
OBJECTS OF THE INVENTION:
Therefore, it is an object of the invention to propose an improved bearing housing with enhanced cooling system which is capable of keeping the oil in the sump of the bearing housing cool.
Another object of the invention is to propose an improved bearing housing with enhanced cooling system which is able to carry higher than normal load and enhance its life expectancy.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:
Fig.l : Shows an air cooled existing bearing house.
Fig.2 : Shows a fluid cooled existing bearing housing.

Fig.3 : Shows a cooled bearing housing according to invention.
Fig.4 : Shows a splash ring with scoops as per the invention.
Fig.5 : Shows a view from bottom without cooling chamber cover of a
cooled bearing housing according to the invention.
Fig.6 : Shows new cooling insert, a view from bottom, according to the
invention.
Fig.7 : Shows cooling chamber cover according to the invention.
Fig.8 : Shows complete assembly of shaft and bearing housing according to the
invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF INVENTION:
Usually, bearing housings are of Cast Iron or Cast steel. Heat created in the bearing may be removed externally and/ or internally.
In existing designs, the bearing housings for anti friction bearing are cooled by any combination of:
1. air- natural convection over the bearing housing body;
2. air- forced convection over the bearing housing body;
3. coolant circulated through conduits in the oil sump;
4. shaft mounted splash ring to cause turbulence in oil sump;
This invention is for further enhancement of cooling the bearing through increased rate of heat removal by
1. jacketing the bearing housing and circulating cooling medium in the enclosure, and
2. providing a splash ring with scoops to effect better lubrication and cooling of the bearing.

The bearing housing of the present invention is made of cast steel.
The hot oil exiting from the bearing is directed through a tube (11) to the bottom of the bearing housing (1), on to the fins of new cooling insert (4). The improved splash ring (10) leads to better mixing in the oil sump. The shaft mounted ring (splash ring with scoops) is provided to splash the oil on the bearing and bearing housing interior. When the ring rotates, the oil gets collected in the scoops which are then splashed on the bearing and inside bearing housing. The jacket cooling provides large heat transfer area.(Fig.3). These measures reduce the bearing temperature further than the prior art thus have the advantage of bearings being able to carry higher loads than earlier.
This beaVing housing is an air and coolant cooled bearing housing for a highly loaded antifriction bearing pump application and for any other similar application. It is for use with all types of antifriction bearing such as angular contact, or deep groove ball bearings, taper roller bearings, spherical roller bearings etc. The lubricating medium in these designs is contained in a sump. It is not effective where forced oil cooling system exists like in say journal/tilting pad type bearings. Hence, this bearing housing can be used for any bearing that is lubricated in an oil sump with no externally induced circulation through a heat sink.
The technical improvement of the invented bearing housing over the prior art is because of (a) provision of larger heat transfer area. The external body of the bearing

housing has been jacketed with intermediate baffles for flow guidance, (b) directing the outlet oil from the bearing over a cooled finned surface. Baffles are plate partitions in chambers with openings to guide the flow in the desired path.
Antifriction bearing life is limited to certain values for a given combination of load and operating speed. These limits arise from the maximum temperature attained by the rubbing surface. Since material hardness reduces at higher temperatures it increases wear. Lubricating medium removes the frictional heat generated in the bearing. Increased cooling will enhance the life expectancy of the bearing. This is particularly significant for heavy duty bearings.
The particular application where we intend to use this design employs taper roller bearings that transmit radial and axial thrusts from the shaft to the bearing housing.
The cooled bearing housing (1) is jacketed which means that it is enveloped. The bearing housing (1) is made double walled on its sides creating a gap in between the walls through which coolant is circulated. (Fig.5). The bearing housing (1) is provided with a splash ring (10) with scooper to effect better cooling in the oil sump. The splash ring (10) has grooves on its circumference and axial holes on its surface. When the shaft mounted ring rotates, the grooves scoop the oil from bottom of their dipping point and the oil is then splashed onto the bearing and upper portion of

bearing housing causing better lubrication/cooling of the bearing (2). The axial holes (14) are positioned in such a way that the oil coming out of it is directed onto the bearing and hence enhancing the bearing lubrication, The splash ring with scooper (10) also imparts turbulence in the oil sump thereby increasing the overall heat transfer rate. (Fig.4)
The bearing housing is also provided with new cooling insert (4) disposed in the housing to receive coolant through a slot (13) in the cooling chamber cover (5). The cooled bearing housing (1) and the new cooling insert (4) are so assembled as to allow the coolant to flow in series from one part to the other. This design enables having single inlet and outlet for the coolant and maintaining a flow passage without any dead zone being created. The cooling insert (4) has concentric circular chambers with vertical baffles (12) at regular intervals. It ensures that the entire cavity of the new cooling insert (4) is always filled with coolant. The coolant enters into the new cooling insert (4) from the outside periphery and gradually moves towards the center through concentric circular passages. Fins are provided on the top surface of the new cooling insert which protrudes into the oil sump. This leads to increased heat transfer from the hot oil to the coolant.

TESTING OF THE INVENTED BEARING HOUSING IN COMPARISON WITH EXISTING DESIGN:
Now in order to establish effectiveness and improvement of bearing housing compared to prior art in causing enhanced cooling of sump oil and antifriction bearing, a test was performed.
TEST APPARATUS:
A barrel type multistage pump of present invention was tested at KSB factory's high pressure pump performance test filed. Test was first performed using a bearing housing of the existing design on the Non Drive End (NDE) side. Test was then repeated under identical conditions but with a bearing housing of improved design (using same bearings). The NDE bearing housing was in both instances externally fan cooled. The test pump had 10 stages with all impellers facing the suction side of the pump. A single piston / drum arrangement is used to partially balance the axial thrust (force / load) of the rotor. The Drive End (DE) of the pump is on the suction side. The rotor is supported on a cylindrical roller bearing on the DE side and with a pair of taper roller bearings in face to face i.e. X-arrangement on the NDE side. Whereas the radial forces of the rotor are shared by the bearings on DE and NDE side, the residual axial thrust (load / force) are entirely taken by the NDE bearing. The heat generation is therefore very high on the NDE side. Fig a) is a representative drawing of the typical design of the pump that was used for the test. The improved bearing housing

design is used only in the NDE side. It is not necessary in the DE side because of low heat generation.
TEST PROCEDURE:
The pump, driven directly by a squirrel cage induction motor, was first operated with a bearing housing of existing design. The pump was started with discharge valve closed. The discharge valve was then opened and adjusted to obtain the desired flow. Readings were started to be taken after the flow had stabilized at this set value. The start of reading was considered as instant zero. Instant zero commenced about 10 minutes after the motor had been switched ON. The pressure differential across the pump, operating speed, ambient temperature, pumped medium temperature, bearing housing sump oil temperature, bearing temperature on outer ring, etc. were measured at regular intervals till all measured parameters were stable.
After observing the temperatures to be stable and steady state conditions having been achieved the pump was stopped. The NDE side bearing housing of existing design was removed and replaced with a bearing housing of improved design. Pump was readied and operated once again as described earlier and readings recorded. However, this time the cooling water flow and temperature rise were additionally measured.

TEST OBSERVATIONS:
Pump operating flow = 35 m3/hr
Pump head / differential pressure = 11.9 N/mm2
Pump operating speed = 2960 rpm
Bearing lubricating oil grade = ISO VG 32
For improved bearing housing on NDE side, Cooling water flow = 1.08 m3/hr
Cooling water temperature rise after stabilization = 1.5° C
Temperature measurements recorded on NDE side are tabulated hereunder:

Testing with bearing housing of existing design
Time instant Ambient Temp Sump oil Temp Bearing
Outer ring
temp Sump oil
Temp rise
w.r.to
ambient
(A) (B) (C) (B-A)
min °C °C °C °C
0 24.7 48 43.5 23.30
5 24.8 52 48.6 27.20
10 24.7 56 54.3 31.30
15 24.8 57 56.5 32.20
20 24.9 58 58.7 33.10
25 24.7 59 60.1 34.30
30 24.7 60 61.1 35.30
35 24.8 60 62 35.20
40 24.8 60 62 35.20

Testing with bearing housing of improved design on NDE side

Time instant Ambient Temp Sump oil Temp Bearing
Outer ring
temp Sump oil
Temp rise
w.r.to
ambient
(A) (B) (C) (B-A)
min °C °C °C °C
0 27.6 47 43.1 19.40
10 27.8 48 46.5 20.20
20 27.6 49 47.3 21.40
30 27.7 51 48.9 23.30
40 27.3 52 52.1 24.70
60 26.6 51 52.8 24.40
80 26.3 51 53.1 24.70
100 26.4 51 53.1 24.60
TEST CONCLUSION:
Some standards stipulate the maximum allowable temperature of oil in sump, bearing outer ring temperature, or stipulate the maximum allowable rise in temperature of oil in bearing sump with reference to the ambient. For example the America Petroleum Institute 'API' 610 or ISO 13709 restrict the sump oil temperature rise to 40°C above the ambient.

The differential temperature of oil in sump of the tested pump with respect to ambient was 35.3°C and 24.7°C with existing and improved bearing housing designs respectively. This shows a clear gain of more than 10°C. This is a very significant gain in terms of safety over design limits.
The operating limit of machinery that are otherwise restricted by antifriction bearing load carrying capability, can be much enhanced using improved bearing housing design. For example, pumps using antifriction bearings can be offered for higher differential pressure services than at present.
The effectiveness of the improved bearing housing in achieving enhanced cooling of sump oil and antifriction bearing is thus established.

WE CLAIM
1. An improved bearing housing (1) with enhanced cooling system characterized by comprising;
a jacket with intermediate baffles for flow guidance enveloping a bearing housing (1) for providing large heat transfer area, the said bearing housing (1) made double walled on its sides creating a gap in between the walls for circulation of coolant;
a splash ring (10) with scooper disposed in the bearing housing for effecting better lubrication and cooling of the bearing in the oil sump; wherein grooves are disposed in the circumference of the splash ring and axial holes (14) on its surface for scooping the oil from bottom of their dipping point and for splashing in the upper portion of the bearing housing causing better lubrication and cooling of the bearing when the shaft mounted ring (10) rotates, wherein the new cooling insert (4) having concentric circular chambers with vertical baffles (12) at regular intervals are disposed in the bearing housing (1) for ensuring the entire cavity of the new cooling insert (4) being always filled with coolant and for allowing the said coolant to enter into the new cooling insert (4) from the outside periphery and to move gradually towards the center through concentric circular passages when fins are provided on top surface of the new cooling inserts (4) protruding into the oil sump for causing increased heat transfer from the hot oil to the coolant.

2. The bearing housing (1) as claimed in claim 1, wherein the said housing is made of cast steel.
3. The bearing housing (1) as claimed in claim 1, wherein the said housing (1) is an air and coolant cooled bearing housing.
4. The bearing housing (1) as claimed in claim 1, wherein the splash ring with scooper (10) are disposed for imparting turbulence in the oil sump for increasing the overall heat transfer rate.