1、Page 1Page:1ReservoirPumpPumpComponents descriptionY1,Y3,Y5,Y7 are called pressure valvesY2,Y4,Y6,Y8 are called pressure relief valvesElectrically actuatedComponents descriptionY1,Y3,Y5,Y7 are called pressure valvesDe-energized,normal openenergized,valves closedComponents descriptionDe-energized,nor
2、mal closedenergized,valves openY2,Y4,Y6,Y8 are called pressure relief valvesComponents descriptionNo-load start up operation When the mill has been at a standstillfor 2 to 4 hours,but just once per 24 hours,the pistons of the hydraulic cylinders are drawn into their end positions(alternately always
3、2 x),in order to ensure an exchange of oil in the area of the seals.In all other cases,the starting procedure begins with pressurizationto the start-up pressure.No-load start up operation and switching on the pump 1.through the non return-valveNo-load start up operation Starting procedure 1Pressuriz
4、ing all the cylinders to the starting pressure.2Balancing of the roller pair units by means of the ultrasonic measuring devices.3After the mill main drive has been running for approx.1 minute(adjustable,one complet table turn)pressurizing to working pressure.Release for starting the mill1Pressurizin
5、g all the cylinders to the starting pressure.Before the main drive starts running,the cylinders must be pressurized to a lower value than the working pressure,in order to reduce the required starting torque.Pressurizing to starting pressure All the pressure valves Y1,Y3,Y5,Y7and the pressure relief
6、valves Y2,Y4,Y6,Y8 are energizedThe pumps are running and.The hydraulic cylinders are pressurizedto the pressure value set at thepressure relief valves Y2,Y4,Y6 and Y82The measured values of the ultrasonic measuring devices are compared.If the difference betweenthe working side and the fixed side of
7、 one roller pair unit is greater than 50 mm,the hydraulic cylinders are balanced.Balancing of the roller pair units by means of the ultrasonic measuring devices.Balancing of the roller pairs units The measured values of the ultrasonicmeasuring devices are comparedIf the measured value at the cylinde
8、r Iis more than 50 mm greater than the measured value at the cylinder II.relief valve Y5 and pressure valve Y2are energizedI I IBalancing of the roller pairs units If the measured value at cylinder IIis more than 50 mm greater thanthe measured value at cylinder I.relief valve Y1 andpressure valve Y6
9、 are energizedThe balancing process is terminatedwhen the differences of the measured valuesbetween the respective ultrasonic measurement devicesare smaller than 50 mm.Balancing of the roller pairs units The rotation of the grinding table determinesthe fixed and the working sidesWorking sideWorking
10、sideFixed sideFixed sideThree limit switches control the working side rods position3The fixed sides will be pressurized to the working pressure.By pressurizing the fixed sides,the piston rods of the working sides are drawn upwards.Then,the working sides will be pressurizedby being drawn downwards ti
11、ll the central limit switches are reached.Pressurizing to the working pressure.Pressurizing to the working pressureAfter the main drive has beenrunning for approx.1 minute.the pump A is switched onand 10 s later,the pressure valvesY1 and Y3 are activatedWorkingpressureWorkingpressureWhen the limit v
12、alues of pressure are reached,the pump is switched off,an the valves are de-energizedABPressurizing to the working pressureBy pressurizing the fixed sidesto the working pressure.the piston rods of the working sidesare drawn towards the limit switchesI“and IV“IIVBAWhen the limit switches I“and IV“are
13、 reached,the pump B“is startedand the valves Y5“and Y7“are energized Pressurizing to the working pressureBAWhen the central limit switchesII“and V“are reached,.IIVand the valves Y5“and Y7“are energized The piston rods are drawntowardsthe limit switches II“and V“.the pump B“is switched offand the pre
14、ssure valves Y5“and Y7“are de-energized Mill in operationIBADuring the mill operation,the roller pair units are continuously balancedand the working pressureat the fixed sides controlledWhen limit switch I“is reached,pump B“is started andY5“energizedWhen limit switch II“is reachedY5“is de-energized
15、and pump B“is switched offIIWhen limit switch III“is reached,pressure relief valve Y6“is energizedIIIand the pressure in the cylinderis reduced until limit switch II“responds againIIMill in operationBAIf the working pressure at the bucket elevator fixed sidedrops below an adjustable MIN valuePump A“is startedand pressure valve Y1“is energizeduntil the MAX valueis reached
