Spiral spring design

[SriMat]

Hi all,

I am using this equipment which has a flat horizontal spiral spring, with 0.0673 mN.m torque capacity.

This is used to measure resistance offered by a fluid when a spindle connected to one end of this spring rotates in the fluid at a particular speed (you might know this application - it is for measuring viscosity of liquids using rotational cylnder technique). So, the sensed deflection has to be only in the horizontal direction.

But, in my case, it so happens that the weight of the spindle is stretching the spiral spring in the vertical direction (measured about 0.6mm of vertical deflection for a 0.3 kg weight of spindle)- which i think is what is spoiling my measurements. Ddoes anyone here have any idea if torque measurements in a flat-horizontal spiral springs suffer due to application of a vertical load and if yes, could you please explain?? If no, why do you think so? The manufacturer is refusing to give any other design specifications of the spring. It would be great if you people could help me with this...

Thank you very much in advance.

Warm regards,
Sreekanth.

 

[israelkk]

Can you provide more detailed photos or drawings of the setup. Can you give more info on the spring dimensions, strip width and thickness, number of active coils, material etc.?

 

[SriMat]

Thanks a lot israelkk. Unfortunately, I have not been able to get any of the drawings or specifications about the spring from the company (its their proprietery info, I guess.) But, last Friday, the manufacturer finally got back to me saying that the maximum weight of spindle we could use on this was 219gms. So, now I have to bother more about reducing the weight (from 300 to less than 219) hanging from the spring and less about the spring design itself (atleast for now) )

Anyways,thank you very much for reading on.
Cheers,
Sreekanth.