Belt conveyor safety system for rmhs (1) copy

belt conveyor safety system for raw materlial handling substation in industry

1. SAFETY FOR BELT CONVEYORS
Presented By : SatyajitPrusty
Roll No. : 35339

3. Safety Equipments
Pull coRdswitch (PCS)
Belt sway switch (bss)
Zero speed switch (zss)
Belt snap switch (bns)
Chute block switch (cbs)
Safety siren

4. Pull Cord Switch
Pull cord switch (Pull cord PCS): Switch also known as Rope
Operated Emergency switch is used as a safety switch to stop the
conveyor belt in case of an emergency. It is also known as pull
switch cord
Terminal
Box
Pull Cord
Rope
Operating
handle
Indication
Lamp

5. OPERATION:
Pullcordswitchismountedonthewalkwaysideoftheconveyorbelt,preferablyat
aboutevery30meters.Whentheropeispulledfromanyside,Theswitchget
operated.Unlessanduntilthehandleisresettonormalpositionmanually,the
switchremainsinoperatedcondition.PullCordSwitchesinstalledalongan
individualbeltareelectricallywiredinseriesandconnectedtothecontrolstation
bycable.ThereforeactuationofanyoneofthesePullCordSwitcheswillstopthe
concernedconveyoruntiltheparticularswitchismanuallyreset.
Pull Cord Healthy
ON OFF
ON OFF
ON OFF
Pull Cord HealthyOperated Pull Cord
As PCS operates Indication lamp
on & on that condition easy to find
out operated PCS

6. LOCATION: Along the conveyor both side preferably at about every 30
meters.
Advantage:
* It is an emergency switch which saves persons from abnormal
condition.
* Saves the Equipment of Belt Conveyors in emergency cases.
PCS
30M
PCSPCS

8. BELTS SWAY SWITCH
BELTSSWAYSWITCH(BSS):Theswitchallowssmoothrunningofthe
conveyorandprotectsitfromdamagesbyoverswayingwhichcanoccurdue
tomisalignmentofbeltorunevenloadingofmaterial,wornoutidlerroller
bearingsetc.BeltswayswitchisalsoknownasRunOffSwitch.
Operating
Lever
Terminal Box

9. OPERATION:
ForNormalrunningofthebeltwithacceptableswaying,thebeltsway
switchisgenerallymountedonbothsidesandneartheedgeoftheconv-
eyor,belt.Asmallclearanceisallowedbetweencontactrollerandthebelt
withacceptableswaying.Whenswayingexceedsnormallimit,thebelt
edgepushesthecontactroller,whichdrivestheswitchandoperatesthe
contacts.Theswitchresetsautomaticallywhenthebeltresumes,normal
running.
BSS
Normal running of the belt,
BSS is Healthy
Swaying of the belt, BSS is
Operated

10. LOCATION: Along the conveyor both side.
Advantage:
* It saves belts from wear & tear.
* Prevent spillage from conveyor.
* Protects human during swing of belts.
* Saves break down time of system.
BSS
50M
BSSBSS

11. Zero speed SWITCH
ZEROSPEEDSWITCH(ZSS):ElectronicSpeedMonitorisusedtomonitor
runningofconveyors.Thisdeviceactuatesrelaycontactsatpresetspeed.Usingthese
contactsdesiredcontrolactionsuchaszerospeedprotection/underspeed
protection/overspeedprotectioncanbeachieved.
Proximity
Controller
Unit

12. OPERATION:
Thebasicprincipleofspeedmonitoriscomparisonofpulsesreceivedfromsensorwithstandardpulses.Theunit
consistsoftwoparts:CONTROLUNITand“SENSORPROBE”.Thesensoristobeinstalledwithitssensingfacein
closeproximityofrotatingobject.Onthisobject,flagsaretobefixed.Thesensorproductsstrongelectromagnetic
waves,whichgetdisturbedbytheflags,givingrisetocorrespondingpulses.Thesepulsesarefedtothecontrol
unitwheretheyarecomparedwithstandardpulsestosensethespeed.
LOCATION:
At tail pulley of the conveyor belt.
Advantage:
* It Senses speed by non-contact way. Hence no moving parts.
* No wear and tears of rollers or misalignment of couplings.
Head Pulley
Tail Pulley
Proximity
Controller
Unit
10-15 mm
Proximity
Sensing
Plate

13. Testing of PNP & NPN Sensor

14. SAFETY Siren
SafetySiren:Forsafetypurposesconveyorbeltsarenormally
equippedwithsirensorwarningbellssituatedsoastowarnpersonsofthe
subsequentstarting-up.Thesesirensorwarningbellsareconnectedto
operateforasetperiodimmediatelypriortothebeltstart-up.

15. OPERATION:
Before starting the conveyor belt Safety siren is on for 30 sec.
LOCATION:
It depends on the length of conveyor belt.
Advantage:
Increases human safety.

16. Monitoring & Indication Unit
Belt watch system
Belt watch System : It is microprocessor based system for
monitoring the real time condition of PCS/BSS & exact position of
actuated PCS & BSS in numeric form. It also has the capability to
communicate with DCS & send the actuated position of switches to DCS
& that data can be used to show on HMI.
Belt Watch
System

17. OPERATION:
Show the exact position & no of PCS & BSS when they actuated.
LOCATION:
Monitoring unit present in Substation Building & sensor shall be mounted in each
of the PCS/BSS. Termination module shall be mounted in the last PCS/BSS.
Advantage:
*Easy & fast detection of actuated PCS/BSS.
*Saves start time of system as detection is very fat.
*Saves breakdown time which directly reduces production loss.

18. Fail Safe Conveyor safety System
24V DC Loop from
Belt Watch
230V AC loop from
MCC
Potential free contacts to DCS
MODBUS Communication from Belt
Watch to DCS
Local Display in Belt Watch

19. Conveyor Group Starting Logic
Path Ready
All interlocks healthy
Group Start Command
Pre warning Hooter Start
Command for 30 secs.
After stopping feedback of Hooter , Conveyors
are started sequentially from Discharge points

20. Conveyor Group Stopping Logic
Conveyors are running in Group Mode
All interlocks healthy
Group Stop Command
After Group Stop command Conveyors are
stopped sequentially from feeding points

21. Interlocking System

22. Conveyor Emergency Stopping Logic
Conveyors are running in Group Mode
If any Of the following Safety interlocks fails
1)PCS
2)BSS
3)ZSS
4)BNS
5)CBS
6)Emergency Switch
Conveyors will stop immediately towards last
conveyor up to feeding point

23. THANK YOU FOR YOUR KIND ATTENTION