Whitworth Bros Ltd, a UK flour milling company, changed its maintenance strategy from reactive to predictive in order to minimize downtime and ensure customer needs were met. They implemented acoustic emission technology, the MHC-Memo Pro system, to monitor critical equipment across sites. This allowed potential issues to be addressed proactively through scheduled maintenance versus reactively after breakdowns. Since installing the user-friendly system, Whitworth Bros has been able to trend machine data, complete 2,500 monthly monitoring points, and reduce unplanned downtime, saving costs. Moving forward they aim to expand monitoring coverage further.
3. Managing mill
maintenance
Maintenance programmes
by Alice Neal, associate editor, Grain and Feed Milling
Technology, United Kingdom
E
very miller knows the
importance of a comprehensive
maintenance programme. There
are numerous strategies out from the
‘if it ain’t broke don’t fix it’ attitude
of reactive maintenance to monitor-
ing-centered predictive maintenance,
the scheduled approach of preventive
maintenance and the precision of
reliability centred maintenance.
Switching strategies is a big change and
therefore needs careful consideration, not
just in terms of which strategy to use but also
how to make a smooth transition between
systems.
This case study looks at why a flour mill
in the United Kingdom, Whitworth Bros
Ltd, chose to change its maintenance pro-
gramme and the technology it used in its
new strategy.
Maintenance case study
Whitworth Bros Limited
Acoustic emission technology prevents hun-
dreds of hours of downtime for century-old
flour specialists.
Established in 1886, Whitworth Bros Ltd
supplies flour to some of the largest food
manufacturers in the UK. The company
operates from production sites located
in Wellingborough, Northamptonshire and
Peterborough, Cambridgeshire and supplies
flour in bulk loads as well as bag deliveries.
As one of the UK’s largest independent flour
millers, Whitworth Bros prides itself
on its ability to supply (its customers with
high-quality food safe products that fulfil
customer expectations). Whitworth Bros
recognises the importance of monitoring
key elements of plant and equipment to
ensure the company is always able to meet
customer demands.
Maintenance strategy challenges
In 2009, Whitworth Bros took the decision
to move from a reactive to a predictive
maintenance strategy. A Whitworth Bros
technician explains the reasons behind the
switch, “Whitworth Bros had witnessed
several occasions where bearing failure
within key plant drive systems had caused
significant disruption to production,
which in turn affected the
company’s ability to meet customer delivery
deadlines”.
“By getting an early warning of possible bear-
ing / gearbox failures of the key production
plant, the company could organise remedial
action which would allow maintenance to
be undertaken in a planned manner and in
timescales that would not adversely effect
the companies ability to deliver first class
service to its customers.”
The main driver for this initiative was to
ensure Whitworth Bros used the best tech-
nology available to minimise any potential
for unplanned production plant downtime.
The necessity to minimise the risk of equip-
ment failure and resulting impact on produc-
tion, led the company to devise a proactive
condition monitoring (CM) strategy.
Part of the switch in maintenance strategies was
to employ a
Grain&feed millinG technoloGy38 | July - august 2013
FEATURE
4. CM technician to implement the system across
its sites. “Employing a dedicated technician to
roll out and monitor plant across the site using
the technology, allowed a rapid roll out across
all facilities and plant issues to be addressed
accordingly,” says the Whitworth CBM techni-
cian.
In terms of technology, the company
considered various monitoring options -
such as vibration and temperature - and
attended numerous trade shows, eventually
discovering the MHC-Memo Pro Acoustic
Monitoring system from Holroyd, part of
Parker Kittiwake.
“Acoustic emission technology was chosen
as it provided the most suitable solution to
effectively monitor the type and volume of
plant used in the Whitworth Bros facilities.”
Whitworth Bros started collating data cap-
ture routes across all its sites and within a
very short time, commenced data acquisi-
tion and analysis.
Solution
With data acquisition routes established,
condition monitoring of the production
critical plant commenced. This enabled
Whitworth Bros to take a proactive
approach to monitoring and mainte-
nance of the equipment at the company’s
Wellingborough and Peterborough sites.
The MHC-Memo Pro readily identified
machines which were in need of reme-
dial action and appropriate preventative
maintenance was undertaken as required.
Machines thought to be beyond routine
servicing, were withdrawn from service as
part of planned maintenance activity.
Whitworth Bros devised a cost metric
calculation to assess the savings to the com-
pany off the back of the newly implemented
CM activity. This approach was very ben-
eficial in help-
ing justify the
expenditure
and resource
costs allocated to
this particular CM
strategy, as well as
balancing the CM
approach against
that of machinery
failure.
Data collection
now takes place on
a regular basis for
all critical plant and
machinery. This
allows engineering
resources to be direct-
ed to the plant in need of maintenance
and this is organised as part of planned,
proactive activity, rather than as a result of
machinery breakdown.
Whitworth Bros uses a suite of sen-
sors that are compatible with the
MHC-Memo Pro system. The stand-
ard magnetic mounted sensor is used
to collect the vast majority of infor-
mation with the hand-held, extended
probe, allowing data capture in hard
to reach areas. Low profile sensors
have also been installed to allow
critical plant data to be gathered. All
three sensors are readily connected
to the MHC-Memo Pro and data can
be captured almost instantaneously.
“The hardware and software associ-
ated with the Memo Pro system
has been very well designed and
constructed. It is portable, robust and
straightforward to use. This function-
ality is mirrored with the analysis soft-
ware, which allows new data to be
quickly downloaded and compared
against historic data for all machines
detailed for each production area.”
Since the equipment was installed,
Whitworth Bros has recognised that
the MHC-Memo Pro is a robust, user-
friendly and comprehensive tool. The data
reduction and analysis software is well-
written, allowing analysis to be completed
in an effective and timely manner.
“The technology requires minimal training
to use and interpret data captured and can
also be used for spot checks as needed.”
Whitworth Bros’ experience of the MHC-
Memo Pro shows the following key benefits:
• Usability - its data collection method is
straightforward and hardware easy to
operate has excellent ergonomics and
is extremely robust
• Intuitive - it doesn’t require intensive
training, “[it] really is a turn-key
solution. Data routes can be compiled
readily, allowing important data to be
gathered and analysis to be undertaken
and completed promptly,” says a
Whitworh Bros spokesperson
• Multiuser application - it offers good
value as it can be used across different
sites due to the multiuser applications
Results
Whitworth Bros currently carry out rou-
tine monthly data capture, supplemented
with weekly collections for any machines
suspected of having an underlying bear-
ing issue. The Memo Pro is also used to
take one-off readings to help correctly
diagnose individual machine issues as they
arise, thus reducing incorrect diagnosis of
plant issues.
Current coverage at the Wellingborough site
sees the collection of data spanning a staggering
2,500 separate data points. This ensures that
a comprehensive dataset exists which allows
machine condition trending to be completed.
Whitworth Bros has devised a cost metric
calculation to assess the savings to the com-
pany off the back of the newly implemented
CM activity. The company recognises that
the CM approach has significantly reduced
the potential for unplanned production
stoppages.
Future
Existing coverage sees the majority of the
Wellingborough site plant captured using
the range of standard sensor products, so
Whitworth Bros are now looking at the
monitoring challenges they face with oscil-
latory equipment (flour sifters) and will be
investigating technology that allows condi-
tion monitoring of these machines.
In collaboration with Holroyd, part of Parker
Kittiwake, Whitworth Bros will continue to
monitor further advances in condition moni-
toring technology with a view to minimising
future plant breakdown and maximising
production efficiency across all of its sites.
More InforMatIon:
Website: www.kittiwake.com
Grain&feed millinG technoloGy July - august 2013 | 39
FEATURE
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