# Thread: Selection of Coil Spring

1. Registered User
Join Date
Oct 05
Posts
23

## selection of coil spring

Please suggest that is there any temperatures factor consider while selecting the spring for vibrating screen.

2. ## springs

and you have to understand that unless you are willing to give us this information we probably wont help with your problem. If you are just looking for information on springs and types it is available at any library.

3. Registered User
Join Date
Oct 05
Posts
23

## Selection of coil spring

Hello Sir,
I used the spring for the vibrating screen,
Size of screen-2.4MX4.8M
Mass of screen-6 Ton
for above screen I select the helical coil spring
Wire dia-26mm, Nos of coils-8.9 and free length-350
Nos of springs-8nos
pl suggest the my selection is correct or not

(1) What is the spring outside diameter?
(2) Are the 8.9 coils the total number of coils - or the number of active coils?
(3) What speed is your screen operating at?

5. Registered User
Join Date
Oct 05
Posts
23
Dear ,
Mr.John Mckenzie,
I mention below the deatails of spring
Total No of coil-8.938
No of active coil-7.43
Outer Dia of coil -242( Privously i mention this is the inner dia but 242 is the outer dia of spring)
Screen RPM-850
Total No. of spring-o8 Nos

I have done a very quick review of your spring selection, which I understand to be:

26mm wire dia
242mm outside spring dia
350mm free spring height
7.43 number of active coils
8.94 total number of coils

Total screen mass = 6,000 kg supported on 8 springs
Vibrating frequency = 850 rpm

By calculation I figure the solid height of the spring would be 232mm, and the spring rate would be approx 6.22 kg/mm.

Assuming that the screen mass (6,000 kg) is equally distributed between the 8 support springs, then each spring will carry 750 kg.

Therefore under the static load of the screen, each spring will compress (750kg / 6.22 kg/mm) = 121 mm, and the compressed height of the spring would be (350mm – 121mm) = 229 mm.

Compare this compressed height (229mm) with the solid spring height at 232mm,and you can see that you have compressed the spring solid just by resting the screen on it !!!

I would be selecting a spring with about 65mm compression under static load, and at least 30mm difference between compressed height and solid height to accommodate the increase bounce at stop/start, and also any heavy material loadings, surges, or material build up around the coils.

As to your original question regarding temperature limitations. Talk to your spring supplier, but I would think that spring steel should be OK up to about 220 degrees centigrade.

7. Registered User
Join Date
Oct 05
Posts
23
Dear Sir,
but same coil can be used by reduced the spring rate 4.0 kg/mm

From my understanding of your problem you need to increase the spring rate (make the spring stiffer), not decrease.

9. Registered User
Join Date
Oct 05
Posts
23

## Spring selection

As per VSMA the screen frequency range can be applied for the horizontal screen.

Some spring steels have better temperature ratings than others. What sort of temperature range do you want to operate at?

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