LBT PROJECT 2x8.4m TELESCOPE
	TECHNICAL SPECIFICATION AZIMUTH RING STRUCTURE
	Doc. 401E018/E Date: August 4th, 1997 Prepared and approved by: Gianpietro Marchiori/EIE

INDEX

1.0 SCOPE OF WORK
2.0 APPLICABLE DOCUMENTS
3.0 ITEM DESCRIPTION
4.0 INTERFACE DEFINITIONS
5.0 PERFORMANCE CHARACTERISTICS
6.0 RELIABILITY, MAINTAINABILITY REQUIREMENTS
7.0 ENVIRONMENTAL CONDITIONS
8.0 DESIGN AND CONSTRUCTION REQUIREMENTS
8.1 General Dimensions and Mass
8.2 Materials
8.3 Class of Welding
8.4 General Tolerances
8.5 Thermal Treatments
8.6 Tightening Torque of Bolts and Screws
8.7 Surface Treatments
8.8 Special Manufacturing Instructions
9.0 PRE-ASSEMBLY
10.0 PACKING AND TRANSPORT
11.0 ACCEPTANCE TESTS
12.0 SPARE PARTS
ANNEX A

1.0 SCOPE OF WORK

The AZIMUTH RING STRUCTURE is one of the elements which constitute the LBT Project.

The aim of the LBT (Large Binocular Telescope) Project is to realise a telescope having two mirrors of 8.4 m diameter, to be installed at Mount Graham in Arizona (ref. dwg. No. 407e001).

The AZIMUTH RING STRUCTURE represents the sliding track of the telescope's hydrostatic bearing system, the support for the AZIMUTH RIM GEAR WHEEL and the encoder system.

It is made up of eight sectors in machined steel structure, assembled each other by means of bolts.

The supply of the AZIMUTH RING STRUCTURE and AZIMUTH RIM GEAR WHEEL includes:

• execution of all workshop drawings and Part Lists, based upon the design drawings included in the Request for Proposal;

• preparation of the Manufacturing Plan;

• selection and purchase of all materials, components, etc.

• preparation of all procedures and methods to execute the critical operations of the manufacturing;

• fabrication of all components;

• fabrication and/or purchase of all tools, necessary for the manufacturing and/or assembly;

• painting or surface treatment;

• performance of checks and tests;

• drawing up of the inspection and check documentation.

2.0 APPLICABLE DOCUMENTS

• Drawings:

Title	Document
Pier/Pier Construction Drawings/Upper Ring/General Assembly Pier/Construction Drawings/Concrete Structure/General Assembly Azimuth Ring Structure/General Assembly Azimuth Ring Structure/Ring Sector 1-3-5-7 sheet 1/3 Azimuth Ring Structure/Ring Sector 1-3-5-7 sheet 2/3 Azimuth Ring Structure/Ring Sector 1-3-5-7 sheet 3/3 Azimuth Ring Structure/Ring Sector 2-4-6-8 sheet 1/3 Azimuth Ring Structure/Ring Sector 2-4-6-8 sheet 2/3 Azimuth Ring Structure/Ring Sector 2-4-6-8 sheet 3/3 Azimuth Ring Structure/Upper Surface Drilling - Rim Gear Azimuth Ring Structure/Upper Surface Drilling - Encoder Azimuth Rim Gear Wheel Azimuth Drive Application/Ring Section	Dwg. 421e037 Dwg. 421e024 Dwg. 410e014 Dwg. 410e015 Dwg. 410e016 Dwg. 410e017 Dwg. 410e018 Dwg. 410e019 Dwg. 410e020 Dwg. 410e021 Dwg. 410e022 Dwg. 460a011 Dwg. 462a010

• Interface Drawings:

Title	Document
Azimuth Ring Structure/Adjusting System Azimuth Measuring System Azimuth Measuring/Lay-out Hydrostatic Pad System	Dwg. 410e023 Dwg. 470a010 Dwg. 470a011 Dwg. 430a010/ 440a014

3.0 ITEM DESCRIPTION

The AZIMUTH RING STRUCTURE (see dwg. 410e014) is made up of the following elements:

• NO.8 SECTORS AT 45°

• NO.32 AZIMUTH RIM GEAR WHEEL ELEMENTS

• VARIOUS BOLTS AND ACCESSORIES (SHIMS, ETC.)

Each sector of the AZIMUTH RING STRUCTURE Is composed by a steel structural work made up of plates with different thickness, cut, finished and assembled by means of weldings.

After pre-machining, each one of those sectors shall be assembled to the other elements forming the ring and machined on an apposite support structure, in order to obtain the tolerances indicated on drawings and at paragraph 8.0.

The main function of the AZIMUTH RING STRUCTURE is to distribute the axial loads of the HYDROSTATIC PADS of the AZIMUTH AXIS, on the telescope's foundations.

The external side of the upper track is interfaced with the AZIMUTH RIM GEAR WHEEL, which is bolted to it, relative to the Azimuth axis' motorization (see dwg. No. 460a011). The directions given on drawings and technical documents with regard to the AZIMUTH RIM GEAR WHEEL represent a construction hypothesis for the obtainment of the requested requirements. The contractor shall submit any other alternative production system that gives guarantee of obtaining the demanded final accuracy with more economical procedures.

The vertical plate, welded on the internal side of the upper track, is interfaced with the ENCODER SYSTEM (strip)(see dwgs. No. 470a010/470a011).

The upper track presents a series of holes for the drainage of the pads' oil through a recovery system (see dwg. No. 462a010). The anchoring to the pier's concrete and the adjustment of the AZIMUTH RING STRUCTURE are performed by the MECHANICAL JACKS, located under the track in two concentric rows (see dwg. No. 421e037).

4.0 INTERFACE DEFINITIONS

The AZIMUTH RING STRUCTURE (see dwg. No. 421e037) is interfaced with the following elements:

• TELESCOPE CONCRETE PIER (dwg. No. 421e024)

• AZIMUTH RIM GEAR WHEELS (dwg. No. 460a011)

• HYDROSTATIC PADS SYSTEM (dwg. No. 430a010/440a014)

• ENCODER SYSTEM (dwg. No. 470a010/470a011)

The interface with the CONCRETE PIER, indicated on the relative drawings, is made up by No. 180 mechanical jacks for the axial fixing of the track and the adjustment of the upper track's planarity, and by means of No. 48 mechanical jacks to contain radial forces and adjust the circularity/concentricity of the upper track.

The interface with the RIM GEAR WHEELS for the motorization of the Azimuth axis, indicated on the pertinent drawings, is realised by a machined mechanical coupling. The fixing to the rack is guaranteed by bolts and consequent broaching.

The upper track represents the interface with the HYDROSTATIC PADS. Particular care and attention should be paid during the machining of the track, in order to obtain the tolerances indicated on drawings, necessary for a correct functioning of the HYDROSTATIC PADS and for the alignment of the telescope's Azimuth axis.

The two rows of holes (concentric) made on track's side, constitute the interface with the pads' oil recovery system. On those holes it shall be fixed some connections for pipes, which conduct oil through the connectors, to the hydraulic box.

The interface with the encoder system is made by a levelled plate, fixed to the upper flange of the internal side's track. Particular care shall be taken to the mechanical machining of the internal surface in contact with the strip.

5.0 PERFORMANCE CHARACTERISTICS

The main performance characteristics of the AZIMUTH RING STRUCTURE are the following:

• sustain the axial loads produced by pads, determined by the functioning of the telescope (No. 4 prints of 0,6 m2 each);

• contain the deformation of the upper track, submitted to the above mentioned loads (measured under pad's print);

• sustain loads introduced by Azimuth axis motorizations;

• sustain vertical seismic loads.

The main performance characteristics of the AZIMUTH RIM GEAR WHEEL are:

Mechanical characteristics of Azimuth axis:

• Torque with wind at 24 km/h: 7317 Nm

• Torque with wind at 80 km/h: 81473 Nm

Driving system characteristics:

• No.4 motors QT-13701 for each axis

• Peak motor torque: 795 Nm

6.0 RELIABILITY, MAINTAINABILITY REQUIREMENTS

The useful lifetime of the telescope is expected to exceed 25 years.

The contractor shall take into account of all aspects which could limit the lifetime of the supply.

He shall also contain the number of maintenance interventions, supply adequate access for maintenance operations and minimise risks of damage, loss and injury to personnel and the telescope from telescope maintenance operations.

7.0 ENVIRONMENTAL CONDITIONS

This chapter defines the natural and induced environmental conditions the telescope and subassemblies will encounter during its lifetime.

• Storage temperature: -30 to +50°C

• Operating temperature: -20 to +25°C

• Storage pressure: 500 to 750 Torr

• Operating pressure: 500 to 600 Torr

• Storage humidity: 5 to 80%

• Operating humidity: 5 to 95%

• Maximum operating windspeed: 80 km/h

• Maximum observing windspeed: 120 km/h

• Survival windspeed: 150 km/h

8.0 DESIGN AND CONSTRUCTION REQUIREMENTS

The scope of the present chapter is to introduce the main characteristics of the supply from a manufacturing point of view.

The contractor shall take care of confirming the adopted criteria, or may propose alternative solutions, in order to obtain the requested performance.

The contractor shall fabricate all parts, equipment, components and materials of the AZIMUTH RING STRUCTURE and AZIMUTH RIM GEAR WHEEL in accordance with the requirements indicated in the present Technical Specification and the applicable drawings.

Subsequent to fabrication, but prior to packaging the materials, the contractor shall store, at its sole expenses, all components, materials and equipment in manner that will reasonably protect such components, materials and equipment against loss or damage.

Suitable allowances for contractor and expansion during welding shall be made in the lengths of the steel parts prior to welding, so that final machined lengths are correct within the acceptance tolerances specified in this Technical Specification and relative drawings. Welding procedures shall be such that distortion and lock-up stresses are minimised. Tack welds, temporary stiffeners, tie bars, controlled peening, pre-heating and stress relieving during welding may be used for this purpose, as approved by P.O..

Surface to be welded shall be dry, clean and free for loose scale, grease, or unsuitable protective paints or coatings.

All welded parts and assemblies, unless specified or approved otherwise by P.O., shall be fully stress relieved prior to final machining operations. Stress relieving shall be accomplished by the heat treatment method in a chamber with sufficient volume and temperature capacity to fully stress-relieve the welded parts and subassemblies.

8.1 General Dimensions and Mass

The general dimensions of the AZIMUTH RING are shown in dwg. No 410e014.

1. Maximum dimensions: 5500mm x 1500mm x 929mm (each sector)

Total dimensions: diameter 15000mm (without rim gear wheel)

1. height 929mm (without rim gear wheel)

2. diameter 15138mm (with rim gear wheel)

Total weight: 9400 kg (each sector without rim gear wheel)

Total weight: 75200 kg

Lifting points: t.b.d. with the contractor

The specific technical data of the RIM GEAR WHEEL are the following:

Azimuth axis:

Outside diameter: 15180 mm

Primitive diameter: 15168 mm

Module: 6 mm

Teeth number of every element: 79

Reference profile: DIN 867

Quality: 6 f 22

Max. error on a tooth: 0.02 mm

Max. error on the joint: 0.03 mm

Max. cumulative error: 0.5 mm

Steel: C 40 UNI 7845

Primitive circumference concentricity: 0.2 mm

8.2 Materials

All materials are indicated on the drawings and relevant Part Lists.

AZIMUTH RING: Fe 510C UNI EN 10025

GEAR WHEEL: C40

Steel plates relevant to surfaces to be further machined shall be supplied with complete Ultrasonic Examination Certificates, according to UNI EU 160/87 or ASME SA-578, acceptance standard level I.

8.3 Class of Welding

All welding operation shall conform to the standards set forth in American Welding Society Specification AWS D1.1 or equivalent approved by P.O..

Welding operations shall be performed in such a way as to guarantee the following mechanical machinings in terms of tolerances, as indicated on drawings. For this purposes, welding procedures shall consider possible shrinkages or expansions during welding operation and minimise the distortion and lock-up stresses.

The contractor shall perform and provide trial welds to demonstrate the soundness of any proposed welding method, and the competence of any person performing welding work, as required by P.O. at any time.

(Butt Joints Complete Penetration:

Class I according to UNI 10011, UNI 11001 and UNI 1307/2.

NDT: X-ray or Ultrasonic examination; acceptance criteria as required for above mentioned class of welding, according to UNI 7278, or welding procedures tests according to EN 288-3.

Welding material	electrode:	according to UNI 5132: Class IVB or according to AWS A5.1: E 7018-1
	wire:	according to AWS A5.20: E 80T5/G

(Corner or T Joints Complete Penetration:

Class II according to UNI 10011, UNI 11001 and UNI 1307/2.

NDT: X-ray or Ultrasonic examination; acceptance criteria as required for above mentioned class of welding, according to UNI 7278, or welding procedures tests according to EN 288-3.

Welding material	electrode:	according to UNI 5132: Class IVB or according to AWS A5.1: E 7018-1
	wire:	according to AWS A5.20: E 80T5/G

(Corner or T Joints Partial Penetration:

Construction: according to UNI 10011, UNI 11001 and UNI 1307/2.

NDT: Magnaflux 60% examination, acceptance criteria category II as per UNI 7278 par.A.4.3.

Welding material	electrode:	according to UNI 5132: Class IVB or according to AWS A5.1: E 7018-1
	wire:	according to AWS A5.20: E 80T5/G

8.4 General Tolerances

For welded parts: CNR-UNI 10011 and UNI 11001.

Tolerances for linear and angular dimensions are specified on relevant drawings. These tolerances are mandatory, for structure acceptance. Where not specified, ISO 2768 part 1/m and 2/k shall be applied.

Particular attention should be paid to obtain the tolerances requested by the AZIMUTH RIM GEAR WHEEL after its assembling on the ring:

Max. height difference between two teeth: < 0.02 mm

Max. height difference between the junction: < 0.03 mm

Max. cumulative error of height: < 0.5 mm

Note: the overmetal indicated on the fabrication of the steel works requires an accurate fabrication (carpentry dimensional tolerances 5÷8 mm). It is up to the contractor to maintain them or to modify them, in order to ensure the successive mechanical machining and relative tolerances. Any modification must be approved by the P.O.

8.5 Thermal Treatments

Complete stress relieving.

Parameters: t.b.d. with the contractor.

8.6 Tightening Torque of Bolts and Screws

According to the following table:

	M48x500
Class	10.9
Force [kN]	805

Note: it is important to grease the screws before tightening them.

Clamping shall be performed with hydraulic bolt tensioner

Grease advised: type OKS 200

Denomination: MoS2 grease or equivalent.

8.7 Surface Treatments

All metallic surfaces, other than rating machining surfaces shall be painted, coated or otherwise permanently protected against atmospheric corrosion.

At a minimum all paints and coatings shall provide for the following functional requirements:

• 25 years service life (with maintenance)

• (two months continuous salt exposure during shipping)

The contractors shall utilise the following paint system in performance of the work.

• sand blasting SA2.5 ISO 8501-1:1988/SS055900:1988

• 1 coat (oil resistant) epoxy polyamide corrosion resistant primer (80 microns)

• 1 coat (oil resistant) vinyl high-build mastic (80 microns)

• 1 coat (oil resistant) vinyl chloride enamel (50 microns)

The supplier can propose an alternative painting cycle; in any case this shall be able to guarantee the above mentioned requirements.

The RIM GEAR WHEELS must be protected with grease SKF LGMT 2/5 or other equivalent product. The surfaces which are machined and not painted shall be protected with protection material of "peeling" type.

8.8 Special Manufacturing Instructions

The contractor will present, in a detailed way, the following documents:

• Weldings specifications and procedures: these have to be approved by the Project Office (P.O.) prior starting the work.

• Fabrication plan and control: these have to be approved by the P.O. prior starting the work.

The directions given on drawings and technical documents with regard to the AZIMUTH RIM GEAR WHEEL represent a construction hypothesis for the obtainment of the requested requirements. The contractor shall submit any other alternative production system that gives guarantee of obtaining the demanded final accuracy with more economical procedures.

Note: the overmetal indicated on the fabrication of the steel works requires an accurate fabrication (carpentry dimensional tolerances 5÷8 mm). It is up to the contractor to maintain them or to modify them, in order to ensure the successive mechanical machining and relative tolerances. Any modification must be approved by the P.O.

9.0 PRE-ASSEMBLY

The AZIMUTH RING STRUCTURE and the AZIMUTH RIM GEAR WHEEL shall be pre-assembled for the completion of the machining, to verify the total dimensions and pertinent tolerances indicated on the drawings (dwg. No. 410e014, 460a011 and 401e004).

Before disassembling for shipment, all couplings shall be opportunely locked by a pin. The eventually required special tooling to perform the assembly and the alignment is part of this Contract supply.

10.0 PACKING AND TRANSPORT

All steel structure shall be packed in such a way as to guarantee:

• the degree of the physical-chemical protections against weather conditions during holding and transportations of goods;

• the degree of mechanical protection for the preservation of the goods during handling and transportation to destination;

• the determination of volume and weight in relation to the transportation means.

11.0 ACCEPTANCE TESTS

The contractor shall prepare and submit to the P.O. the Acceptance Test Plan.

The following tests and inspections shall be performed prior to Plant Acceptance, and shall be included in the Acceptance Test Plan:

• certificate of raw material and fasteners;

• certification of welding procedure and welding control;

• stress relieve certification;

• dimensional control, machining tolerances, roughness test;

• mass check;

• certificate of surface treatment;

• certificate of assembly tolerances.

12.0 SPARE PARTS

If it is adopted a solution of RIM GEAR WHEEL with sectors, the contractor shall supply No. 2 sectors completed with bolts.

ANNEX A

Doc_info_start
Title: AZIMUTH RING STRUCTURE
Document Type: TECHNICAL SPECIFICATION
Source: EIE
Issued by: G.MARCHIORI
Date_of_Issue: 04/08/97
Revised by:
Date_of_Revision:
Checked by:
Date_of_Check:
Accepted by:
Date_of_Acceptance:
Released by:
Date_of_Release:
File Type:MS-WORD 6
Local Name: C0301/DOC/401e018e.doc
Category: TELESCOPE AZIMUTH PLATFORM
Sub-Category: GENERAL TELESCOPE
Assembly: TELESCOPE TECHNICAL DOCUMENTS
Sub-Assembly: AZIMUTH RING STRUCTURE
Part Name:
CAN designation: 401e018
Revision: e
Doc_info_end