Krmiljenje mazalnega sistema vročega ravnalnika

ROŽIČ, MATIC (avtor), Nedeljković, David (mentor)

V diplomskem delu je opisan projekt predelave mazalnega sistema ravnalnega stroja, ki je namenjen ravnanju jeklenih plošč v železarski industriji. Glavne ravnalne valje poganjajo trije električni motorji. Mehanski prenos moči je zaradi predvidenega obsega hitrosti izveden preko reduktorjev. Vsi premikajoči se deli so za učinkovito ter gladko in dolgotrajno delovanje potrebni stalnega mazanja. Mazalni medij, ki kroži po mazalnem sistemu vročega ravnalnika, je olje. Mazanje se izvaja z brizgalnimi šobami, ki so usmerjene v zobniške prenose znotraj reduktorja. Pretoki olja v starem mazalnem sistemu so bili previsoki. Varnostni ventil je posledično zaradi previsokega tlaka delež olja spuščal direktno nazaj v oljni rezervoar. Ta delež pretoka olja ni opravljal koristnega dela in je s tem v sistemu predstavljal čiste izgube. Pretoke olja smo zmanjšali s pomočjo frekvenčnega pretvornika in z njim napajali črpalkin asinhronski motor. Z zmanjšanjem napajalne frekvence motorja smo posledično zmanjšali vrtilno hitrost črpalke in s tem tudi pretoke olja in izgube v mazalnem sistemu. Delovanje mazalnega sistema smo s konstantnega mazanja predelali na različne načine delovanja. Sistem vzdržuje normalno mazanje med samim valjanjem plošče, a ko ravnalnik čaka na ploščo, sistem preide v varčevalni režim. Program smo spisali v programskem orodju Proficy Machine Edition in ga naložili na programirljivi logični krmilnik (PLC) znamke Fanuc. Ta preko obstoječih zunanjih signalov na liniji zaznava morebitno prisotnost plošče v bližini vročega ravnalnika in sproži ukaz za začetek mazanja sistema. Vklope raznih nastavitev ter vpogled v trenutna stanja sistema smo prikazali na uporabniškem vmesniku podjetja – SCADA. Na koncu so vse rešitve pripeljale do zmanjšanja porabe električne energije ter ostalih stroškov vzdrževanja mazalnega sistema vročega ravnalnika. Sistem je tako postal bolj učinkovit ter zaradi manjše porabe električne energije tudi bolj ekonomičen.

• Jezik: Slovenski jezik
• Ključne besede: mazalni sistem, vroči ravnalnik, kavitacija, programirljivi logični krmilnik, frekvenčni pretvornik, uporabniški vmesnik, redundanca
• Vrsta gradiva: Diplomsko delo/naloga
• Organizacija: FE - Fakulteta za elektrotehniko
• Leto izida: 2015
• PID: 20.500.12556/RUL-73451
• Datum objave v RUL: 17.11.2015

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Control of the Hot Leveller Machine's Lubrication System

Izvleček

The following thesis discusses the upgrade project of the lubrication system of the hot leveller machine, designed for levelling steel plates in steel industry. Nine main rolls are driven by three electric motors. Mechanical power transmission is implemented through the reductor and pinion stands due to the desired speed and the required torque. Continuous lubrication is required to obtain efficient, smooth and long-lasting operation of mechanical parts. The used lubricating medium is the oil which circulates through the lubrication system of the hot leveller machine. Lubrication is carried out by spraying nozzles, which are focused on gears within the gearbox. I have discovered that the result of oil flow through the lubrication system was too high. Consequently, the safety valve was passing some oil directly back to the oil tank due to excessive pressure. This part of the oil flow has not carried out work that was useful and resulted in net loss. At that point I reduced the oil flow while using a variable frequency drive to control the rotational speed of the pump's induction motor. By reducing the frequency I consequently reduced the pump speed and hence the flow of oil which caused loss in the lubrication system. Furthermore, I implemented two operational modes of lubrication system. During the rolling of a plate, the system maintains a normal lubrication. However, when the rolling is completed and the hot leveller is waiting for the plate to roll, the lubrication is switched to saving mode. The program was written in the Proficy Machine Edition programming tool and loaded on a Fanuc programmable logic controller (PLC). PLC detects the possible presence of a plate near the hot leveller and triggers the command to start the lubrication system in normal mode. Various settings and current states of the system are displayed on the user interface – SCADA. In conclusion the solution resulted in the reduction of power consumption and other maintenance costs of the lubricating system of hot leveller. The system has become more efficient and more economical due to lower power consumption.

• Ključne besede: lubrication system, hot leveller, cavitation, programmable logic controller, variable frequency drive, human machine interface, redundancy