1. BeginningNext SlideBack End Program AVADAL 1 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE

2. BeginningNext SlideBack End Program AVADAL 2 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE The function of this module is to provide the correct fluid pressure to all nine roller apron segments depending upon demands and conditions prevalent at the time. All roller apron movements are made using only LP system. High pressure movements of a jammed machine can cause damage. High pressure system 0 is used during casting and performs a holding action, provides make up fluid and prevents great losses of fluid should a line rupture. The LP system is also used on segments when dummy bar is inserted to prevent damage.

3. BeginningNext SlideBack End Program AVADAL 3 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE The module consists of a directional valve, two check valves, a flow control valve and a pressure switch. 1.) The 4 way, 2 position, detented, double solenoid valve is used to induce or block high pressure into the roller apron segments. When solenoid RA-MHO is momentarily energized the valve spool shifts allowing high pressure to all nine roller segments.

4. BeginningNext SlideBack End Program AVADAL 4 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE DIRECTIONAL FLOW CONTROL VALVE (High Pressure Mode)

5. BeginningNext SlideBack End Program AVADAL 5 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE When solenoid RA-MLP is energized the valve spool shifts, stopping all high pressure to roller segments and vents fluid between check valve and operating valve back to tank. Due to the detent feature this valve once shifted will maintain its position until opposite solenoid is energized, thus during a power failure, the pressure condition will not change.

6. BeginningNext SlideBack End Program AVADAL 6 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE DIRECTIONAL FLOW CONTROL VALVE (Low Pressure Mode)

7. BeginningNext SlideBack End Program AVADAL 7 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE 2.) The variable flow control valve is used to prevent large fluid loses if a line ruptures while casting operation is in progress. 3.) The two check valves inhibit all reverse flows. The valve prevents pressure from venting back through directional valve to tank or system O (power failure of main HP system could cause pressure drop). The check valve prevents the high pressure system 0 from entering the LP system.

8. BeginningNext SlideBack End Program AVADAL 8 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE 4.) The function of pressure switch PKSW-RA is to signal high pressure on roller apron segments. The signal is transmitted along with SK-1 limit switch signal to the Ready to Cast check system and also High Pressure indicator on operator stations.

9. BeginningNext SlideBack End Program AVADAL 9 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE DIRECTIONAL FLOW CONTROL VALVE (High Pressure Mode) CHECK VALVE PRESSURE SWITCH (High Pressure) RETURN SYSTEM CHECK VALVE

10. BeginningNext SlideBack End Program AVADAL 10 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE The pressure switch SAF (C) on the main accumulator valve and pressure switch module provide permissive to energize either solenoid MHO or MLP on high pressure valve only if main valve is open. Solenoid MLP is energized permanently as long as anyone of the seven limit switches in SK-1are actuated. The indicator lights on operator station High Pressure On and High Pressure Off may be both lit in the on position since pressure is not able to bleed off pressure switch until one of the valves in SK-1 is operated. This condition will not indicate a malfunction of equipment, only a inherent design peculiarity.

11. BeginningNext SlideBack End Program AVADAL 11 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE System changeover to high pressure by remote control will be locked out electrically until all limit switches at manual valves in SK-1 Indicate regular valve protection. Pressure condition, low or high, must be maintained in case of power failure,

12. BeginningNext SlideBack End Program AVADAL 12 of 12 SK-2 ROLLER APRON SEGMENTS HIGH PRESSURE MODULE Since low pressure only moves cylinders, high pressure flow is to be limited to maintain make-up fluid and prevent great losses of fluid should a line break. Factory set pressure switch, furnished by others and shop mounted by hydraulic vendor, indicates high pressure presence. Movement is controlled only by manual valves at SK-1.