[Sharma*, 5(3): March, 2016] ISSN: 2277-9655
(I2OR), Publication Impact Factor: 3.785
http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology
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IJESRT
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH
TECHNOLOGY
RELIABILITY AND PROFIT EVALUATION OF COMPRESSOR SYSTEM
DESCRIBING FAILURES AND DEAL WITH FAILED UNIT ON PRIORITY
Dr. Upasana Sharma
*
, Jaswinder Kaur
*
Associate Professor , Department of Statistics, Punjabi University Patiala, India
Lecturer, Department of Community Medicine,Gian Sagar Medical College,India
DOI: 10.5281/zenodo.48324
ABSTRACT
The paper presents reliability and profit evaluation of compressor standby system comprising of two units.Initially
one unit is operative and the other is in standby state. On failure of any one of the compressor unit, the standby unit
becomes operative to keep the system in operating state. If both the compressor units get failed then system goes to
down state. Here compressor unit can fail due to three types of failure which are serviceable, repairable and
replaceable type. Out of two compressor units, the unit which fail earlier will get facility of service, repair or
replacement. System is analyzed and expressions for various reliability measures such as MTSF, Availability, Busy
periods for varioustypes of failures and profit etc have been computed numerically by using semi-Markov process
and regenerative point technique Graphs for profit are plotted for making the present study more useful.
KEYWORDS: Compressor unit, Standby system ,Regenerative point technique , semi-Markov process .
INTRODUCTION
In milk plants for functioning of refrigeration system compressor standby system act as a vital organ. Upon the
failure of this system , it has been observed that working of refrigeration system get effected seriously. In field of
reliability standby systems have been analyzed by large number of researchers such as [ 1]-[7].Compressor standby
system is still untouched in the field of reliability. The present paper is our genuine effort to study such system and
to fill this research gap .Paper present reliability and profit evaluation of compressor standby system comprising of
two units.Initially one unit is operative and the other is standby state. On failure of any one of the compressor unit,
the standby unit becomes operative to keep the system in operating state. If both the compressor units get failed then
system goes to down state. Here compressor unit can fail due to three types of failure which are serviceable,
repairable and replaceable type. Out of two compressor units, the unit which fail earlier will get facility of service,
repair or replacement. Upon failure of second compressor unit if the first compressor unit is still in service, repair or
replacement then this unit will be kept in waiting state for service, repair or replacement.System is analyzed and
expressions for various reliability measures such as MTSF, Availability, Busy periods for service,Busy period for
repair ,Busy period for replacement and profit etc have been computed numerically by using semi-Markov process
and regenerative point technique Graphs for profit are plotted for making the present study more useful. For profit
purpose the unit real failure as well as repair time data from a milk plant have been collected.
NOTATIONS
O
I
First Compressor is in Operative State
S
II
Second Compressor is in Standby state
F
sI
, F
sII
Failure category of Serviceable type for First, and Second compressor
F
rI
,F
rII
Failure category of Repairable type for First and Second compressor
F
repI
,F
repII
Failure category of Replaceable type for First and Second compressor
F
wrII
, F
wsII
,F
wrepII
Second compressor is waiting for Repair, Service and Replacement respectively
F
usI
,F
urI
,F
urepI
First compressor is under Service, Repair and Replacement respectively