Vacuum system

Principal scheme

Vacuum parameters 1 Preliminary vacuum 1*10-2 Pa 2 Melt storage 3 Crystal annealing 5*10-5 Pa

Mechanical pump. Construction and principle of operation.

Two Stage Rotary Vane Vacuum Pump Inlet and outlet Oil level 3 phase engine Oil removal

Gas flow in rotary pump 1, 7 –stages, 2,3 – valve, 4 – gas outlet, 5- gas channel, 6 – gas inlet

Vacuum characteristic

Diffusion pump

Structure of diffusion pump 1 – body; 2, 10 – covers; 3, 11 – washer; 4 – oil reflector; 5 – earth; 6 – vapor path; 7 – spiral way; 8 – heater;

Oil reflector Stage Cooling water

Vacuum characteristic Speed l/sec Input pressure, torr

Electromagnetic valve. Solenoid principle of operation.

Vacuum lock. Construction and principle of operation. Cover Engine Manual close ring

Structure of lock

Vacuum meter APG. Principle of operation. 1- electric cable, 2- socket, 3 – spring ring, 4-vacuum flange, 5-filter

Principle of operation Pirani TO MEASURE VACUUM BY MEASURING HEAT CONDUCTIVITY OF GAS Heater wire Thermocouple

Vacuum meter WRG. Principle of operation. WRG – combination of inverse magnetron sensor and Pirani Way of measuring is chosen automatically

Principle of operation Dependence of ionized gas current on pressure Crossed magnetic field make longer path of ions before reach anode E H - +

Plant assembly

Vacuum line is fixed to the frame by Joining crystallizer with 3 bolts Joining right angle tube with 2 bolts Vacuum devices and parts are mutually fixed with clamps and rings

To set the crystallizer on the frame and to fix it with the bolts

To join the vacuum tube to crystallizer and frame by means of the bolts and the studs

To join the lock and diffusion pump by means of the studs

To set the side shields and to fix them with the screws

To set up vacuum devices

To set up water tube with water collector Pressure meter

Water collector

Water piping 1-Valve 2-Pressure meter 3-12 –Valves of the grower parts 13- Diffusion pump 14-Thyristor 15 – Chamber 16 –Bottom 17- Small cover 18- Big cover 19 -Rod 20-Cutter 21- Current lead 1 22- Current lead 2 23-34 –Thermal sensor of the elements 35- Funnel

To set and fix with the bolts the column to the frame

To set and to fix the computer control board

To set the supports and to adjust them in order to provide for horizontal orientation of the grower

Assembly of hot zone inside the crystallizer Bottom Support Side shield W Tube

Checking the center of W-tube and the gap

Mo shield and W-tube Bottom shield Shield to the current lead

Bottom shield Support Granules Bottom shield

Al2O3 loading

To put on and to fix the big cover with the nuts

Heater

Small cover Window Lobe

To set and to fix bus bars with the bolts

To set and fix the side shields on the frame

To set the transformer unit

To set the mechanical vacuum pump

Maintenance Checking for vacuum seals and junctions Checking of water cooling system Checking for thermal screens and hot zone elements wear Correction of crucible position

Safety measures Electrical safety There are the following sources of electric safety: chains of power supply of the component parts of the grower,panels and blocks with electric apparatus and electric equipment, located on the control panel, crystallizer, power cabinet. Protection of maintenance staff against electrical shock is provided by the doors which can be opened by special key and by protective grounding. There are grounding bolts with special marks on the doors of the power cabinet and control unit.

Danger of thermal burns. There are the following sources of thermal burns: the heater, screens and the melt surface at monitoring of crystallization front through non-protected window, therefore after termination of technological process it is allowed to open the grower only after its complete cooling. To protect the eye of process engineer from thermal irradiation at monitoring of seeding process it is necessary to use the light filter.