Is our interpretation correct? What fits are required between the cylinder and the mating parts? What is the purpose of this cylinder in the floating lateral pads, 440a010? Is the designer confident that the contact loads will seal the oil from reaching the bolt holes without additional seals?
Answer 1. We confirm that each support is tilting enough to compensate the sliding geometrical inaccuracy and deflections. The interpretation is correct: The bending of the cylinder provides the pad rotational freedom of 0,1 mm/1000mm maximum. The fit between the cylinder and the mating parts at both ends must be flat without backlash. (Roughness Ra 1,6 micron, and flatness 0,005 mm is enough.) The purpose of the cylinder is also to center the support in such a way to avoid any contact between the floating part and the fixed part, on the external diameter near the Glydring seal, ( for the floating supports as well ). The backlash on the external diameter can be about 0,1 mm on the radius, enough for the seal at the working pressure.The rotation gives negligible radial movement during the rotation of the support. The cylinder is centered inside the fixed part without backlash, and with a little backlash to permit the little displacements with the floating part. Indeed there is a little leak of oil through the screws, but it is very very small, it doesn't influence the pressure, and goes where there is already a lot of oil. Anyway a seal can be added if desired.
Answer 2. The 4 central pieces are referred to here are the same as the cylinders in question 1. The supplementary 4 cylinders, and 16 bolts, are provided in order to permit the modification of a Fixed Support and make it become a Floating Support. The central cylinders are the only aspect which is different between a Fixed Support and a Floating Support. The reason for this is so that we can change (with some hard work) the amount of kinematic overconstraint which we apply to the elevation structure of the telescope.
We want to have:
Our apologies: The drawing numbers 440a107a and 400a010a are typographical errors. The correct drawing numbers are 440a017a and 440a010a which you already have.
Answer 3. Each hydrostatic support is equipped with four pressure transducers to ensure contact absence during movement. The transducers are indeed pressure transducers.
Answer 4. The units of cooling capacity in Italy are "Frigories/Hour". The correct conversion is:
1.0 F/hour == 0.00116 kW == 3.3e-4 Tons of Refrigeration == 4 BTU/hour
For example 30000 F/h is equal to 35 kW.
Answer 5. The flow is indicated by Nl/h or "normal litres per hour", in other words the air volume at atmospheric pressure per hour.
Answer 6. The drawings don't show the oil outlet connections. These oil outlet connections are two for each support, connected to the groove 10 mm width and 10 mm deep, at two opposite sides of the support. On drawing 440a014a marker (7) is located halfway between (1) and (4).
Answer 7. The "azimuth and elevation encoder hardware" includes all the pieces that support the slider (readout head) for the Farrand strip encoders, between the structures (shown in the lower part of the drawing 440a010b) and the wheel bearing, both included.
Answer 8. Yes, it is correct.
Answer 9. Yes, it is correct. The lever moves the centered joint between the two extreme positions. The ball bearing is necessary because the joint is rotating with the shaft.
Answer 10. The supply is only to include the heat exchangers. LBT will supply the external plumbing, chilled water/glycol from a central source and chiller control.
Answer 11. Be assured that as astronomers we are not interested in obtaining your proprietary technology of fabrication. However, we do have the concern of assembling our large telescope on a remote mountaintop in Arizona, so we want to be sure that all the parts work correctly and are well documented when they arrive. The purpose of the detail drawings is to assure that the fabricated parts meet the requirements of the telescope for both dimensional compatibility and function. We think that the "detailed construction drawings" could be substituted with a set of "detailed interface drawings" and "assembly drawings" which did not reveal proprietary fabrication know-how. These drawings would need to specify the precise dimensions and tolerances of the parts. The same Italian engineers which would examine the construction drawings would also inspect the finished parts before their acceptance by LBT.
Answer 12. Yes, we would accept and alternate proposal for a system of your design. You may submit an alternate proposal without replying to the original proposal. Clearly such an alternate must meet our dimensional and performance requirements as outlined in the Technical Specifications and the design report.
Answer 13. We agree to extend the deadline by two weeks. A longer extension would have a negative impact on our overall bidding schedule. The new deadline is October 17, 1997 at 5:00 p.m..