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Introduction :
Bearings are needed to transfer the vertical forces from one structural member to another. They are also required to restrict or permit linear movement. Where horizontal movement is restricted, the horizontal force will be transferred through bearing to the lower structure.
Application :
SNEHA make PTFE and SS Bearings have wide applications in the field of :
Bridges : Plate grinder, Truss, Arch, Suspension Cable Stayed, Movable
Structural : Building, Sports Complex, Auditoriums, Pipe Supports, Vessel Supports, Gantry Supports.
Pollution Control : Precipitators, Bag houses, valves, Ducts.
Off Shore : Platforms, Turn Tables, Crain Pivot.
Oil & Chemical Refinery Equipments : Heat Exchangers, Pipe lines, Hanger Bearings.
Click Images for Details:- |
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Rocker Bearings (NTF) |
Rocker Bearings (NTF1) |
Rocker Bearings |
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Model EDF |
Pot Bearings |
Pot Bearings |
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Spherical Bearings |
Spherical Bearings |
Plain Sliding Bearings |
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Duct Support |
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Properties of PTFE :
The wonder material PTFE (Polytetrafluroethylene) possesses following properties
Application :
Chemically inert
Low coefficient of friction
High wear resistance
Immune to almost all known solvents
Can operate over wide range of temperature.
Friction :
The exact value of coefficient of friction can not be quoted, since it depends on many factors, some of the major governing factors are :
Unit Loading.
Surface finish of mating parts.
Temperature.
Speed of movement.
Period under load without movement.
The dynamic coefficient of friction can be as low as 0.005, but for design considerations the coefficient of friction is taken as 0.05.
Advantages of PTFE / S.S. Bearings :
Low coefficient of friction.
No maintenance required.
No lubrication required.
Life Long.
High Load carrying capacity.
Compact in size.
Testing :
The wonder material PTFE ( Polytetrafluroethylene ) possesses following properties
Sample bearings are tested for 1.25 times design load capacity
A pair of bearings, selected at random is tested for coefficient of friction.
Sample bearings also tested for permissible rotation.
All the tests are carried out on finished products in house on sophisticated test rig. |
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1.0 |
Design |
As per BS : 5400Sec.9,1., IS 800, IRC, MOST Specification and Standard Practice. |
2.0 |
Raw Material |
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2.1 |
Mild Steel |
M. S. Plates shall confirm to IS 2062 Grade 'B'. Necessary physical and chemical Test Certificates shall be
furnished by manufacturer. |
2.2 |
Cast Steel |
If Cast steel is used, it will confirm to IS 1030 Gr. 30-57 W. Rectification of casting shall be done as per IS 1030 and 5530. Necessary physical chemical and ultrasonic test. Certificates will be submitted by the manufacturer. |
2.3 |
Stainless Steel |
Stainless steel shall confirm to AISI 304 (ASTM A - 167). Chemical Test Report will be submitted by the manufacturer. Stainless surface is polished to better than 0.15 micron CLA. Surface Finish Test Certificate will be furnished by manufacturer. |
2.4 |
PTFE |
Is pure virgin and pure quality, which confirms to BS 5400 Sec. 9.2 and BS will be > 3784. Thickness 4.5m.m. Manufacturer Certificate will be furnished. |
3.0 |
Fixing |
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3.1 |
Welding |
Welding will be done as per process confirming to IS 9595 with electrodes of suitable grade as per IS 814. Pre-heating and post weld stress relieving will be done as per IS 9595. Welding is tested by dye penetrant, Soundness of welding
will be certified by the manufacturer. |
3.2 |
Bonding |
PTFE Sheet and S. S. Sheet will be vacuum bonded with the help of epoxy resin to the backing plates. |
4.0 |
Corrosion Protection and Painting |
Two Coats of epoxy primer and one coat of each of epoxy intermediate and finish paint with total dry film thickness not less than 150 Microns Silicon grease will be applied to mating parts such as PTFE and Stainless Steel. |
5.0 |
Dimensional Inspection |
All bearings will be checked for overall dimensions and sample Inspection Report will be furnished by the manufacturer. |
6.0 |
Acceptance Test on Bearings |
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6.1 |
Friction Test |
One pair of bearings will undergo for friction test. Coefficient of friction will be less than 0.05 at the design load. |
6.2 |
Load Test |
All bearings will be tested for load at 1.1 times design load. |
6.3 |
Rotation Test |
Two bearings selected at random will be tested for rotation. |
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