The system in figure 1 schematic of a nomadic incineration unit. The equipment is arranged as a skid mounted bundle, recess and out pipes have been disconnected from unit.for the care purpose unit can be skiding out to open infinite and accessing needed constituents straight, or subsequently taking constituents from the unit in order to derive the entree. All supply and waste connexion are from the unit. Because of cramped conditions. Figure 2 it shows the forepart and side positions of the unit is 2.5m tallness, 5m deep, 2m broad. [ 1 ]
Components:
Heat money changer ( EX )
Rotary kiln ( RK )
Scrubing unit ( SC )
Temperature accountant ( TC )
Fan motor ( FM )
Screw feeder ( SW )
Screw motor ( SM )
Feed hopper ( FH )
The kiln, heat money changer, and scrubber are each secured to border by 6 bolts and there are 4 connexions to each of the motors. The whole unit can be slid out to let care utilizing raising cogwheel and this requires 20 proceedingss to hale out and 40 proceedingss to return. The clip takes to take nuts and bolts 2 proceedingss and the clip takes to replace 5 proceedingss [ 1 ]
MTTR ( Average Time To Repair ) is besides known as Mean Corrective Tim - Mct, or TC. is colored norm of the fix times for the system.
( a ) ( I )
Calculation of MTTR when the unit is slid out for fix:
Here failure constituents are removed from unit and it will be repaired and replaced to unit.
Components:
Heat money changer ( EX )
Rotary kiln ( RK )
Scrubing unit ( SC )
Temperature accountant ( TC )
Fan motor ( FM )
Screw feeder ( SW )
Screw motor ( SM )
Feed hopper ( FH )
Formula for MTTR:
TE†c = [ a?‘ni=1 ( I»i.Tc ( I ) ) ] / a?‘ni=1 ( I»i )
Where:
TE†c ( I ) is the disciplinary clip for the i'th unit.
I»i is the failure rate of the i'th unit.
N is the figure of unit. [ 2 ]
Failure informations ( I» ) :
Heat exchanger failure rate ( I» ) = 40 ( failure per 10^6hours ) or 40A-10^-6hours [ 3 ]
Rotary kiln ( I» ) basic constituents of a rotary kiln are the shell, the furnace lining liner, support tyres, rollers, driven cogwheel and internal heat money changer. So rotary kiln failure rate we may gauge amount of all constituents which are utilizing to do rotary kiln.
Under technology premise rotary kiln failure rate ( I» ) = 30 ( failures per 106hours ) or 30A-10-6 hours
Under technology premise Scrubbing unit failure rate ( I» ) = 45 ( failures per 106hours ) or 45A-10-6hours
Under technology premise fan failure rate ( I» ) = 57 ( failures per 106 hours ) or 57A-10-6
Corrective clip for constituents ( Tc ) :
( Tc ) = Tdet + Tloc + Tpla + Tsel + ( Tpre / Tlog ) + ( [ Trem + Trep ] /Trip ) + Tver + Tstu
Tdet = observing mistake
Tlo = placement failure
Tpla = be aftering the work
Ts = select the failed point
Tpre = shutdown & A ; readying
Tlog = logistics clip
Trem = remotion of failed point
Trep = replacing of failed point
Trip = repair-in-place
Tver = verify the repaired point
Tstu = re-start [ 4 ]
Corrective clip for heat money changer ( Tc )
Heat money changer has four connexions in the unit and heat money changer framed by 6 bolts and nuts so clip to take take that constituent ( heat money changer )
Entire nuts and bolts for the heat money changer in the unit = 6
Time taking to take bolts and nuts at each connexion = 2 proceedingss
So clip taking to take heat exchanger = 6A-2 = 12 proceedingss
Time taking to replace bolts and nuts at each connexion = 5 proceedingss
Time taking to replace heat money changer = 6A-5 = 30 proceedingss
And we have to unplug the connexions here we have entire 4 connexion
Time taking to unplug pipe line the unit line from whole unit
Unpluging pipe line from temperature accountant it will take clip = 20 proceedingss
Unpluging pipe line from fan it will take clip = 25 proceedingss
Unpluging pipe line from rotary kiln it will take clip = 40 proceedingss
Unpluging pipe line from another connexion it will take clip = 20 proceedingss
Connecting pipe line to temperature accountant it will take clip = 25 proceedingss
Connecting pipe line to fan it will take clip = 35 proceedingss
Connecting pipes line to rotary kiln it will take clip = 45 proceedingss
Connecting pipe line to another connexion it will take clip = 30 proceedingss
Corrective clip for heat money changer ( Tc ) = 12+30+20+25+40+20+25+35+45+30 =282 proceedingss or 4.7 hours
Corrective clip for rotary kiln ( Tc )
Rotary kiln has four connexions connexions in the unit and rotary kiln framed by 6 bolts and nuts so clip to take take that constituent ( rotary kiln )
Entire nuts and bolts for the rotary kiln in the unit = 6
Time taking to take bolts and nuts at each connexion = 2 proceedingss
So clip taking to take rotary kiln = 6A-2 = 12 proceedingss
Time taking to replace bolts and nuts at each connexion = 5 proceedingss
Time taking to replace rotary kiln = 6A-5 = 30 proceedingss
And we have to unplug the connexions here we have entire 4 connexion
Time taking to unplug the unit line from whole unit
Unpluging pipe line from prison guard motor it will take clip = 23 proceedingss
Unpluging pipe line from heat money changer it will take clip = 30 proceedingss
Unpluging pipe line from another connexion it will take clip = 25 proceedingss
Unpluging pipe line from another connexion it will take clip = 20 proceedingss
Connecting pipe line to sleep together motor it will take clip = 28 proceedingss
Connecting pipe line to heat exchanger it will take clip = 35 proceedingss
Connecting pipe line to another connexion it will take clip = 25 proceedingss
Connecting pipe line to another connexion it will take clip = 40 proceedingss
Corrective clip for rotary kiln ( Tc ) = 12+30+23+30+25+20+28+35+25+40 = 268 proceedingss or 4.46 hours
Scrubing unit has four connexions in the unit and framed by 6 bolts and nuts so clip to take take that constituent ( scouring unit )
Entire nuts and bolts for the scouring unit in the unit = 6
Time taking to take bolts and nuts at each connexion = 2 proceedingss
So clip taking to take scouring unit = 6A-2 = 12 proceedingss
Time taking to replace bolts and nuts at each connexion = 5 proceedingss
Time taking to replace scouring unit = 6A-5 = 30 proceedingss
And we have to unplug the connexions here we have entire 4 connexion
Time taking to unplug the unit line from whole unit
Unpluging pipe line from fan it will take clip = 25 proceedingss
Unpluging pipe line from another connexion it will take clip = 30
Unpluging pipe line from another connexion it will take clip = 35
Unpluging pipe line from another connexion it will take clip = 25
Connecting pipe line to fan it will take clip = 30 proceedingss
Connecting pipe line to another connexion it will take clip = 33
Connecting pipe line to another connexion it will take clip = 38
Connecting pipe line to another connexion it will take clip = 30
Corrective clip for scouring unit ( Tc ) = 12+30+25+30+35+25+30+33+38+30= 288 proceedingss or 4.80 hours
Fan has besides four connexions with whole unit
Unpluging pipe line from heat money changer it will take clip = 25 proceedingss
Unpluging pipe line from temperature accountant it will take clip = 30
Unpluging pipe line from scouring unit it will take clip = 33
Unpluging pipe line from fan motor it will take clip = 27
Connecting pipe line to heat exchanger it will take clip = 30 proceedingss
Connecting pipe line to temperature accountant it will take clip = 33
Connecting pipe line to scouring unit it will take clip = 38
Connecting pipe line to fan motor it will take clip = 30
Corrective clip for fan unit ( Tc ) = 25+30+33+27+30+33+38+30= 246 proceedingss or 4.10 hours
Table 1: Technetium for the when the unit is slid out for fix
Component
I» ( failures per 106or A-10-6hours )
Tc ( hours )
I» . Tc
Heat money changer
40
4.70
188
Rotary kiln
30
4.46
133.8
Scrubing unit
45
4.80
216
Fan
57
4.10
233.7
a?‘I»=
172
a?‘I»Tc=
771.5
Tc = a?‘I»Tc / a?‘I» = 771.5 /172 = 4.48 hours
The MTTR ( Average Time To Repair ) when the unit is slid out for fix = 4.48 hours
( a ) ( two )
Calculation of MTTR when the unit is repaired in topographic point:
Here we have to cipher MTTR ( Average Time To Repair ) whole unit in topographic point
Components:
Heat money changer ( EX )
Rotary kiln ( RK )
Scrubing unit ( SC )
Temperature accountant ( TC )
Fan motor ( FM )
Screw feeder ( SW )
Screw motor ( SM )
Feed hopper ( FH )
Formula for MTTR:
TE†c = [ a?‘ni=1 ( I»i.Tc ( I ) ) ] / a?‘ni=1 ( I»i )
Where:
TE†c ( I ) is the disciplinary clip for the i'th unit.
I»i is the failure rate of the i'th unit.
N is the figure of unit. [ 5 ]
Failure informations ( I» ) :
Heat exchanger failure rate ( I» ) = 40 ( failure per 10^6hours ) or 40A-10^-6hours [ 6 ]
Rotary kiln ( I» ) basic constituents of a rotary kiln are the shell, the furnace lining liner, support tyres, rollers, driven cogwheel and internal heat money changer. So rotary kiln failure rate we may gauge amount of all constituents which are utilizing to do rotary kiln.
Under technology premise rotary kiln failure rate ( I» ) = 30 ( failures per 106hours ) or 30A-10-6 hours
Under technology premise Scrubbing unit failure rate ( I» ) = 45 ( failures per 106hours ) or 45A-10-6hours
Under technology premise fan failure rate ( I» ) = 57 ( failures per 106 hours ) or 57A-10-6
Corrective clip for constituents ( Tc ) :
( Tc ) = Tdet + Tloc + Tpla + Tsel + ( Tpre / Tlog ) + ( [ Trem + Trep ] /Trip ) + Tver + Tstu
Tdet = observing mistake
Tlo = placement failure
Tpla = be aftering the work
Ts = select the failed point
Tpre = shutdown & A ; readying
Tlog = logistics clip
Trem = remotion of failed point
Trep = replacing of failed point
Trip = repair-in-place
Tver = verify the repaired point
Tstu = re-start [ 7 ]
here we do n't necessitate to take constituents from unit for fix
Corrective clip for heat money changer ( Tc ) :
Heat money changer has four connexion in the whole unit
Time taking to unpluging the unit line from whole unit
Unpluging pipe line from temperature accountant it will take clip = 20 proceedingss
Unpluging pipe line from fan it will take clip = 25 proceedingss
Unpluging pipe line from rotary kiln it will take clip = 40 proceedingss
Unpluging pipe line from another connexion it will take clip = 20 proceedingss
Connecting pipe line to temperature accountant it will take clip = 25 proceedingss
Connecting pipe line to fan it will take clip = 35 proceedingss
Connecting pipes line to rotary kiln it will take clip = 45 proceedingss
Connecting pipe line to another connexion it will take clip = 30 proceedingss
Corrective clip for heat money changer unit ( Tc ) = 20+25+40+20+25+35+45+30 = 240 minute or 4 hours
Corrective clip for rotary kiln ( Tc ) :
Unpluging pipe line from prison guard motor it will take clip = 23 proceedingss
Unpluging pipe line from heat money changer it will take clip = 30 proceedingss
Unpluging pipe line from another connexion it will take clip = 25 proceedingss
Unpluging pipe line from another connexion it will take clip = 20 proceedingss
Connecting pipe line to sleep together motor it will take clip = 28 proceedingss
Connecting pipe line to heat exchanger it will take clip = 35 proceedingss
Connecting pipe line to another connexion it will take clip = 25 proceedingss
Connecting pipe line to another connexion it will take clip = 40 proceedingss
Corrective clip for rotary kiln ( Tc ) = 23+30+25+20+28+35+25+40 = 226 minute or 3.76 hours
Corrective clip for scouring unit ( Tc ) :
Unpluging pipe line from fan it will take clip = 25 proceedingss
Unpluging pipe line from another connexion it will take clip = 30
Unpluging pipe line from another connexion it will take clip = 35
Unpluging pipe line from another connexion it will take clip = 25
Connecting pipe line to fan it will take clip = 30 proceedingss
Connecting pipe line to another connexion it will take clip = 33
Connecting pipe line to another connexion it will take clip = 38
Connecting pipe line to another connexion it will take clip = 30
Corrective clip for scouring unit ( Tc ) = 25+30+35+25+30+33+38+30 = 246 proceedingss or 4.10 hours
Corrective clip for fan ( Tc ) :
Unpluging pipe line from heat money changer it will take clip = 25 proceedingss
Unpluging pipe line from temperature accountant it will take clip = 30
Unpluging pipe line from scouring unit it will take clip = 33
Unpluging pipe line from fan motor it will take clip = 27
Connecting pipe line to heat exchanger it will take clip = 30 proceedingss
Connecting pipe line to temperature accountant it will take clip = 33
Connecting pipe line to scouring unit it will take clip = 38
Connecting pipe line to fan motor it will take clip = 30
Corrective clip for fan unit ( Tc ) = 25+30+33+27+30+33+38+30= 246 proceedingss or 4.10 hours
So based on computations and observation MTTR ( Mean To Time Repair ) for unit is slid out for fix is significantly more than unit is repaired in topographic point.
Table 2: Technetium for the when the unit is repaired in topographic point
Component
I» ( failures per 106or A-10-6hours )
Tc ( hours )
I» . Tc
Heat money changer
40
4.0
160
Rotary kiln
30
3.76
112.8
Scrubing unit
45
4.10
184.5
Fan
57
4.10
233.7
a?‘I»=
172
a?‘I»Tc=
691.0
Tc = a?‘I»Tc / a?‘I» = 691 /172 = 4.01 hours
The MTTR ( Average Time To Repair ) when the unit is slid out for fix = 4.01 hours
Mentions: ( 1 ) ( a ( I ) ) ( a ( two ) )
[ 1 ] Plant dependability and maintainability, assignment inquiry paper, faculty ( CPE6250 ) held on November 30 to December 3 2009.
[ 2 ] [ 4 ] [ 5 ] [ 7 ] Cris Whetton, ility technology. Maintainability. [ Lecture press release ] .from works dependability and maintainability, faculty ( CPE6250 ) held on November 30 to December 3 2009.
[ 3 ] [ 6 ] Frank P. Lees, 1996, Loss bar in the procedure industries, 2nd edition, volume 3.
1b )
Design alterations to cut down Mean Time To Repair ( MTTR ) :
To accomplish optimal MTTR the undermentioned design consideration are recommended:
The heat exchanger stuff must be considered based on the operating temperature of the liquid
More dependable and maintainable stuff used in the rotary kiln
Better we have one more scouring unit to cut down the Mean Time To mend MTTR
Motor capacity must designed based on chilling demands
All the pipe parametric quantities must be based on the operating temperature of the liquid throwing it
Material which is utilizing to do all constituents should be defy all status
The temperature accountant must be calibrated for the liquid temperature
1c )
Instrumentality which has system is utile to find the mistakes.so instrumentality in this system temperature accountant ( TC ) : Here TC maps to modulate the temperature of the liquid come ining the heat money changer that is, it pre-controls the liquid come ining the heat money changer. As shown in the figure, the temperature accountant modulate the temperature of the liquid released from the heat money changer and before being cooled by the fan which is control by fan motor. So temperature accountant is utile to observing the mistake which may happen in the heat money changer.
Based on the given figure it can be likely assume that degree index may be used for the rotary kiln. a flat index is placed at the top of the rotary kiln. This is used is indicate the maximal degree of the mixture that can be accommodated in a rotary kiln. So this may be indicated the mistakes if anything occur. A flow rate valve is placed in the scrubber unit, so as to command the flow rate alkalic solution into the scouring unit. This flow rate valve allows merely the coveted sum of solution in to the scouring unit. Once the coveted degree is reached the valve will automatically close off the flow of liquid into the unit. And we have some detector dismay at the fan and fan motor and screw motor why because if these have any jobs will gives the signals so we can easy find the mistakes.
Due to the incorporation of these instrumentality into the chief system the opportunities of failure is significantly reduced
2 )
Question description:
Procedure works to respond liquid A and liquid B to bring forth merchandise C. liquid A passing into storage A utilizing liquid accountant. From storage it will pump to reactor. Liquid B go throughing into storage B utilizing liquid accountant from storage B to pumping to reactor. From reactor merchandise C coming out. Acid gas from reactor pumping to scouring unit. In scouring unit acid gas is cleaned utilizing alkalic solution which is go throughing into scouring unit. Scrubing unit leaves impersonal waste watercourse. Liquids ever available at the recesss to the procedure. There is at least two scouring units working right for the procedure. Stand-by pumps switch over automatically. Pipe work failures can be ignored. [ 1 ]
Available informations:
The computing machine system has a dependability of 0.9997 over one twelvemonth
The operator dependability over one twelvemonth is 0.85 for indicated mistakes and 0.95 for mistakes which raise an dismay
Scrubber unit has a weilbull failure characteristic with I· = 600 yearss, I? = 60days, and I? = 1.8
Reactor failures can affect the fomenter which has two failure manners.
Shaft break failure rate = 0.1/year
Motor failure rate = 0.3/year [ 1 ]
2 ( a ( I ) )
Fault tree analysis here merchandise fails to run into specification is the top event
Alarm failure
Liquid control
LAL fails
Liquid control
Low degree
High degree
Agitator failure
Coking job
Motor failure
Shaft break
High degree
Low degree
Excess flow of liquid Angstrom
Excess flow of liquid B
Reactor
Pump failure
2 ( a ( two ) )
Fault tree analysis here liquid waste watercourse composing outside bounds is the top event
Low degree
High degree
Internal mal maps failure
Connection fails between scrubbers
Improper cleansing temperature
Improper alkaline solution pumping to scrubber unit
Scrubber unit failure
Improper flow reactor to scrubber
High degree
Low degree
Low degree
High degree
2a ) computation of dependability of parts of the system
Here parts of the system:
Storages
Reactor
Agitator
Pumps
Scrubing unit
Dependability of reactor:
Here reactor failure can affect the fomenter failure. First one is shaft break and 2nd one is motor failure
Failure rate of shaft break = 0.1/year
Failure rate of the motor = 0.3/year
Scrubber unit has a weilbull failure characteristic with I· = 600 yearss, I? = 60days, and I? = 1.8 [ 1 ]
Failure rate of pump ( I» ) = 13A-10-6hours [ 2 ]
Dependability of shaft break:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6 [ 3 ]
Failure rate of shaft break = 0.1/year
So utilizing this we are happening T
Z ( T ) = I?/I·I? ( t-I? ) I?-1
0.1/year = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
Here one twelvemonth = 365 yearss
0.1/365 = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
T = 90.11 yearss
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
= 0.995
So dependability for shaft break = 0.995
Dependability of motor:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
Failure rate of the motor = 0.3/year
So utilizing this we are happening T
Z ( T ) = I?/I·I? ( t-I? ) I?-1
0.3/year = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
Here one twelvemonth = 365 yearss
0.3/365 = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
T = 177.29 yearss
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
= 0.948
So dependability for motor = 0.948
Dependability for scouring unit:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^I?
Here we have the T = 133.6 yearss
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Z ( T ) = ( 1.8/ ( 600 ) 1.8 ) A- ( 133.6-60 ) 1.8-1
Z ( T ) = 0.2/year
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^I?
= 0.996
So dependability for scouring unit R ( T ) = 0.996
Dependability of pump:
Failure rate of pump ( I» ) = 13A-10-6hours
Dependability of pump R ( T ) = e-I»t
Surviving clip t = 70 yearss
One twenty-four hours = 24 hours
Surviving clip T = 1680 hours
Dependability of pump R ( T ) = e-I»t
= vitamin E ( -13A-10^-6A-1680 )
Dependability of pump R ( T ) = 0.978
Mentions:
[ 1 ] Plant dependability and maintainability, assignment inquiry paper, faculty ( CPE6250 ) held on November 30 to December 3 2009.
[ 2 ] Frank P. Lees, 1996, Loss bar in the procedure industries, 2nd edition, volume 3.
[ 3 ] Cris Whetton, ility technology. Failure information analysis. [ Lecture press release ] .from works dependability and maintainability, faculty ( CPE6250 ) held on November 30 to December 3 2009.
2b )
Reliability block diagram for the complete system
Pump 1
Storage A
Pump2
Scrubing unit
Reactor
Pump
Storage B
computation of dependability of the complete system over one twelvemonth:
Here parts of the system:
Storages
Reactor
Agitator
Pumps
Scrubing unit
Dependability of reactor:
Here reactor failure can affect the fomenter failure. First one is shaft break and 2nd one is motor failure
Failure rate of shaft break = 0.1/year
Failure rate of the motor = 0.3/year
Scrubber unit has a weilbull failure characteristic with I· = 600 yearss, I? = 60days, and I? = 1.8 [ 1 ]
Failure rate of pump ( I» ) = 13A-10-6hours
Failure rate of fan ( I» ) = 57A-10-6hours [ 2 ]
Dependability of shaft break:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6 [ 3 ]
Failure rate of shaft break = 0.1/year
So utilizing this we are happening T
Z ( T ) = I?/I·I? ( t-I? ) I?-1
0.1/year = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
Here one twelvemonth = 365 yearss
0.1/365 = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
T = 90.11 yearss
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
= 0.995
So dependability for shaft break = 0.995
Dependability of motor:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
Failure rate of the motor = 0.3/year
So utilizing this we are happening T
Z ( T ) = I?/I·I? ( t-I? ) I?-1
0.3/year = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
Here one twelvemonth = 365 yearss
0.3/365 = ( 1.8/ ( 600 ) 1.8 ) A- ( t-60 ) 1.8-1
T = 177.29 yearss
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^6
= 0.948
So dependability for motor = 0.948
Dependability for scouring unit:
Equation for failure rate:
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Here I? = form factor
I· = characteristic life
I? = location parametric quantity
T = lasting a clip
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^I?
Here we have the T = 133.6 yearss
Z ( T ) = I?/I·I? ( t-I? ) I?-1
Z ( T ) = ( 1.8/ ( 600 ) 1.8 ) A- ( 133.6-60 ) 1.8-1
Z ( T ) = 0.2/year
Equation for the dependability:
R ( T ) = e- ( ( t-I? ) /I· ) ^I?
= 0.996
So dependability for scouring unit R ( T ) = 0.996
Dependability of pump:
Failure rate of pump ( I» ) = 13A-10-6hours
Dependability of pump R ( T ) = e-I»t
Surviving clip t = 70 yearss
One twenty-four hours = 24 hours
Surviving clip T = 1680 hours
Dependability of pump R ( T ) = e-I»t
= vitamin E ( -13A-10^-6A-1680 )
Dependability of pump R ( T ) = 0.978
Dependability of the complete system over twelvemonth R ( T ) = norm of system parts dependability
= ( 0.995+0.948+0.996+0.978 ) /4 = 0.979
Therefore dependability of the complete system over twelvemonth = 0.979
Mentions:
[ 1 ] Plant dependability and maintainability, assignment inquiry paper, faculty ( CPE6250 ) held on November 30 to December 3 2009.
[ 2 ] Frank P. Lees, 1996, Loss bar in the procedure industries, 2nd edition, volume 3.
[ 3 ] Cris Whetton, ility technology. Failure information analysis. [ Lecture press release ] .from works dependability and maintainability, faculty ( CPE6250 ) held on November 30 to December 3 2009.
2c )
To accomplish a mark dependability of 0.90 over one twelvemonth:
Reliability mark is a nothing failure mark. This is an of import mark implied for those low acting workss, such workss does non accomplish certain ends designed by applied scientists. So we have to put appropriate mark to accomplish works design. the dependability of the system must be improved to accomplish the mark. to accomplish the dependability mark or to better dependability three basic ways must be employed.
By system design
By component specification
By preventative care
By system design: -
The basic regulation of our system design is to maintain the design has simple as possible. the system is more dependable if the system is simple. Some of the stairss include,
System simplification:
To cut down the complexnesss in procedure works at the design phase its ego
Decrease in the usage of Complex parts by replacing them with more cardinal parts
The design should be made simple and easy to under base
Decrease in constituent count:
The figure of constituents used in the works must be reduced. complex constituents must be avoided for the simpleness of the design.
Mistake tolerance:
The basic features of mistake tolerance require:
No individual point of failure
No individual point of repair- the system must run without any break during the procedure of fix when the system experiences any jobs.
Mistake isolation to the neglecting component- in instance of failures the failed portion of the system must be isolated from the pained system. This requires necessary failure sensing mechanism.
Fault containment to forestall extension of the failure
Handiness of reversion modes- some failures may do cripples to the full system, to avoid the full procedure system must force to the safe manner
By component specification:
For the dependability of a constituent it must be adequately specified for their full length of service. Extra dependability can be provided by runing the constituents at lower emphasis so their operating emphasiss. By making so early failures of the constituents can be reduced. in a procedure industry it is really hard to better dependability merely by specification. This is attributed to the deficit of necessary informations sing the affect of emphasiss on the constituents. Components of high quality can non be used ever for economic grounds. Normally the parametric quantities required to better dependability frequently contradict with procedure demands. Some of the dependability betterments include:
Use of disciplinary maintenance- it is defined as the care which is required to mend and convey merchandise after the fix is carried out. it is carried out in constituents who is failures does n't impact of the overall working of the procedure system significantly. This activity chiefly involves fix, Restoration or replacing of constituents.
Design improvement-the design of any high quality procedure works is based on the design parametric quantities and proficient specifications. the reactor design must be improved for high rates of efficiency. Temperature, force per unit area and other external considerations must be included in the design of reactor and storage armored combat vehicles.
Quality control-Quality control assures conformity to specifications. quality control checks whether measurings of the constituents like reactors, storage armored combat vehicle, scrub units as in this instance conform to the demands.
Preventive care:
Is defined as a care carried out to forestall failure or warring out of constituents in the procedure works. This is carried out by supplying systematic review, sensing and bar of inchoate failure.
The preventive care attempts are aimed at continuing the utile life of equipment and avoiding premature equipment failures, minimising any impact on operational demands. In add-on to the everyday facets of cleansing, adjusting, lubricating and proving. it is carried out merely on those points where a failure would hold expensive or unacceptable effects e.g. reactors, storage armored combat vehicles, scouring units. Many of these points are besides capable to a statutory demand for review and preventative care. [ 1 ]
