Hi!
I have a client for whom I performed a structural/mechanics-of-materials design review for a thickener arm rake mechanism. The rake will operate in an existing thickener tank. The tank has a relatively short wall (~10') and a sloping floor with outside diameter in the range of 40'. The rake mechanism employs four arms, two shorter and two longer. The rake arms "rake" the product that has precipitated from the liquid and deposited onto the sloped floor. The client was intending on making drawings for a replace-in-kind arrangement for the rake. The client issued IFC drawings a few weeks ago. He's since located the drawings showing the original rake arm details. Our latest IFC drawings appear to show two differences compared to the original drawings. The differences are:
1. The rake blades on the original drawings have varying depth. For example, the blades at the tip of the longer arms are ~2" depth compared to the blades near the underflow at ~4" depth. The current IFC drawing set has all blade depth at 3".
2. The blade clearance to the floor varies based on the radial position. For example, the blades at the tip of the longer arms clear by about 2" and the blades near the underflow clear the floor by 3".
We're wondering if we should ask the fabricator to change the rake arm angle and vary the blade depth to make the details the same. If there are any rake arm experts or amateurs out there, please reply with your experiences and advice on whether we should make a change to the IFC drawings we issued recently.
An image attached to help with clarity of the arrangement and specific details I'm asking about.
I have a client for whom I performed a structural/mechanics-of-materials design review for a thickener arm rake mechanism. The rake will operate in an existing thickener tank. The tank has a relatively short wall (~10') and a sloping floor with outside diameter in the range of 40'. The rake mechanism employs four arms, two shorter and two longer. The rake arms "rake" the product that has precipitated from the liquid and deposited onto the sloped floor. The client was intending on making drawings for a replace-in-kind arrangement for the rake. The client issued IFC drawings a few weeks ago. He's since located the drawings showing the original rake arm details. Our latest IFC drawings appear to show two differences compared to the original drawings. The differences are:
1. The rake blades on the original drawings have varying depth. For example, the blades at the tip of the longer arms are ~2" depth compared to the blades near the underflow at ~4" depth. The current IFC drawing set has all blade depth at 3".
2. The blade clearance to the floor varies based on the radial position. For example, the blades at the tip of the longer arms clear by about 2" and the blades near the underflow clear the floor by 3".
We're wondering if we should ask the fabricator to change the rake arm angle and vary the blade depth to make the details the same. If there are any rake arm experts or amateurs out there, please reply with your experiences and advice on whether we should make a change to the IFC drawings we issued recently.
An image attached to help with clarity of the arrangement and specific details I'm asking about.
