SUBMERSIBLE PUMPS -MAINTENANCE

As these pumps are submerged all the time, most of us tend to overlook the maintenace of it
Most failures are detected only when the pump stops pumping and by then , maintenace cost will be high as the seal leaked and electric motor got burnt , bearings damaged and motor stator
could also be damaged

It is highly recommended that preventive maintenance be carried out seriously . mechanical seals and bearings replaced as schedule.This will save pump from unnecessary damages

While Submersible pumps are easy to istalled and save space , it is sometime to costly to
maintain compared to end suction or self priming pumps

Verticle sump pump will be another option and very little maintenance are needed
However ,the pump is usually costly

MAXIMUM PRESSURE?

Do Not specify Head as Maximum 16 bar

Specify the Operating Pressure

Pump Manufacturer may specify Maximum Working pressure as 16 bar on the catalogue
but it does not mean that the pump can operate with a discharge pressure of 16 bar

A pump with a discharge pressure of 8 bar and 16 bar .makes a huge difference in term
of Pump Size & the Motor KW

As I had always mentioned if you are not sure of the Discharge Head ,check the Guages of existing unit or Calculate

Also .when you increase flow for the same diameter of pipeline,the discharge head increases as well
For Bulking Installation ,pumping for factories to Ship the pipeline is usually quite long ,
and this is make a huge difference in pumping head

Suction Line is equally important , as pumps are located at Pumping Station a distant away
from the Tank Farm .When level in the tank drop ,the NPSH avialable is the system will also
drop . Cavitation will take place .One way of ditecting is looking at the running ampheres

VELOCITY IN PUMPING

For new pumps and piping projects , especially for high viscous products it is necessary to
working out the velocity of flow before deciding on the pipe size (most will straight away decide on the pipe size )
The ideal velocity for discharge line should be between 1 to 3 meter per second
and suction between 0.5 to 1.5 Meter /sec

Higher velocity means smaller pipe being used ,thus higher head loss and this mean pump
operates at higher pressure , and higher head means higher Kw of drive or bigger size of pump

On the cost factor , the piping cost will be lower but power cost will be higher
Work out total cost of piping for different size and compare with power cost and see the saving achieveable
This is applicable to high capacity pumping rate . small pumps will not affect much

Suction line is usually more critical .There is one bulking plant where suction line diameter
is to small and pump located far away from tankyard , all these resulted in extremley low NPSH
avialable , at 0.20 meter . Any upgrading of pump is not possible to achieve the required capacity as any pump will be operate in cavitating condition . Replacing the suction line system will cost a bomb .

Looking at this comparison , a pump operating at 9 bar and another at 6 bar

model : 200-500 -------------------------200-500
capacity : 450 m3/hr at 9 bar ------------450 m3/hr at 6 bar
motor Kw : 150 Kw ----------------------95 Kw


See the huge difference in motor kw ( 60% )?

Understanding of Sanitary And Stainless Steel Products

Again ,we came across another established Company using Sanitary Pipes ,SS storage tanks
for milk related products as raw material BUT....Cast Iron Gear Pumps and something is really
wrong here

Also .some Ball Valves used non sanitary but Standard industrial valves
Looks like there is a mixed up or ignorant

When we talk about sanitary pumps in food industry , we talk about cleanability which means how thoroughly the pump can be clean manually or CIP.And there are few levels of cleanability
for each requirement.Pharmaceutical will require the highest

And not just the pump being shining or looks clean


Management plays a very important part , as most tend to be overly conscious about cost
and the Engineering department may have difficulty in explaining between the product and
price .The mindset is always " go for the cheapest " in most SMEs and engineering department
is always under pressure to go for the lowest

CENTRIFUGAL AND PD PUMPS FOR MILK AND MILK PRODUCTS

With the China Milk Products contamination, which is extremely serious ,it is high time we look
at Compliance seriously

Contaminations can come from raw material , production and even equipment used in the
production .There are various established International Standard and Guidelines. some of which are as follow

3-A This standard has the purpose of establishing and documenting the material ,
fabrication and installation (where appropriate) requirements for the engineering
design and technical construction files for all porducts ,assemblies and sub-assemblies
supplied by the manufacturer .The manufacturer has to be in compliance with the
sanitary criteria found in 3 -A Sanitary Standards pr 3-A Accepted Practice , which is
for dairy and food processing equipment

ALL ALFA LAVAL PUMPS RANGES CONFORM TO THIS 3-A STANDARD

FDA The Food and Drug Administration(FDA) in the USA is the enforcement agency of the
US Goverment for food ,drug and cosmetics manufacturing
All The manufacturer of food ,drug and cosmetics in the USA are required to that
products are safe

USDA The United States Department of Agriculture (USA ) primarily responsible for
regulating biotechnology in the United States

EHEGDG European Hygenic Equipment Design Group was formed in the European
Community to promote hygiene during processing and packaging of
food products



Hope the Malaysian Food Manufacturers will be more aware of the such requirements
and more importantly the desire to Hygenic Operation
However ,very rarely we find manufacturer mentioning of any compliance requirement
for the intended purchase of the equipments /pumps . Seem that the only concern is
what is the lowest price , compliance disregarded

Upgrading Pumping Capacity with Present Piping System

Today ,there is a customer with pump Model 65/32 at 1450 rpm ,the rating is 42 m3/hr at 35 M head.
He wants a bigger pump of 150 m3/hr at ?(mentioned maybe about 8 bar ).A pump supplier will
surely be safer to offer this rating .right ? After all the pump supplier is not bearing the
energy cost

Again, it is rather difficult to find Engineer that would work out the System Head before
deciding to upgrade

If we estimate at 8 bar ,the pump size will be much bigger and motor probably be 75 Kw
and if we estimate at 5.8 bar ,the motor of 45 Kw is sufficient

In this case ,it may be necessary to upgrade the pipe diameter and operate at about 4 bar
you will enjoy considerable energy cost as 30 kw motor is sufficient with pump of 80/20

The Engineer should work out the Piping Upgrading cost versus Energy consumption

All we need to do is go back to Basic ,that is back to reference book

Many many of us still do not read enough ,agree ?

Pump Pressure Not Enough ( SEREMBAN JOB )

This is another common issue
A contractor called and inform that pressure not enough , when earlier given was

a) Given
Capacity : 20 m3/hr at 42 m Head ( 4.2 Bar )
Pump Speed : approx 2100 rpm( slurry pumps )

b) Offered pump with same operating parameter and
same operating speed

c) later called and say need to operate at 6 bar

d) This is an indication that the user is not aware or not knowing what is his
requirement , which is 6 bar

e) what can be done

1) as pump is belt driven . adjust the pulley diameter to the required speed
and with reference to pump curve , there has been cases of people guessing the
speed and do many changes before arriving at the required speed and head

2) the motor 15 hp was designed for working pressure of 4 .2 bar at 2150 rpm
therefore the motor has to be upgraded to the required BHP ( 18.5 kw ) .Again ,remember
to refer pump curve

Above is a very simple issue , but the first thing that come to the user's mind

" hey . your pump lousy man , can only reach 4 bar "

" your motor too small lah ..that is why cannot reach 6 bar ''

What is being highlighted here is that . if the User knew what he wanted and
size the pump correctly . there is no waste of time doing further modification which
also incur additional cost,,,

Specifying Pump Head or Discharge Pressure

This has always been an issue all the while .Users tend to give pump head without actually determining the correct discharge head .For convenient purpose ,we will assume the head as
correct and this often leads to problems like motor tripping etc

What will happen ?
When the actual system head is 30 M instead of 60 M , the pump will be operating on the
extreme right of the curve ,maximum flow and low head ( 140 m3/hr at 30 m instead of
90 m3/hr at 60 M)

The result
a) 90 m3/hr at 60 M, the BHP is approx 40 Hp
b) 140 m3/hr at 30 M , the BHP is 55 HP

For the case ,you can either trim the impeller to smaller diameter
or Throttle the discharge valve ( never throttle the suction line )

This pump is open Impeller Slurry pump and supplied with 60 Hp motor 2900 rpm
A 40 hp could be used if the head is 30 M ( 90 m3/hr at 30 M

Take note the power difference

It must be emphasize that giving the actual operating head is extremely important
much saving can be made from

a) smaller pump being used
b) Pump can operate at 1450 rpm instead of 2900 rpm if head is low ,lower wear& tear
c) smaller motor Kw and in long run energy saving
d) long term lower maintenance cost for smaller pumps

Pump Certification

There are various certification for pumps and and equipment
As an example

ATEX
a) Some Plant may require ATEX Certification from Europe and these are pumps are not
common .The prices can be extremely high and delivery is also very long period
EBSRAY PD pumps can be supplied with ATEX, details fo Atex can be obtained from the websites


b) Bomba (Malaysia )
For Fire Fighting application ,pumps supplied must be under the BOMBA approved list
and EBSRAY Streamline Series is under Bomba Approved List

c) Lloyd'S REGISTER QUALITY ASSURANCE

Allen Gwyness pumps are certified under Lloyd's Quality Management System

And there are many others Standard of requirement say API for Oil and Gas users

Food or Pharmaceutical Companies may require Traceability Certifcate by manufacturers
Our Alfa Laval Pumps does come with this on request and chargeable

I will continue to update on this Topic

Memahami "Pressure ' dari Segi Halangan

Pressure adakala tidak mudah difahami dari aspek praktical bagi kebanyakan jurutera . Dalam sistem Piping . ia lebih mudah dipandang dari segi Halangan atau"resistance " .Bermakna . piping yang lebih kecil mempunyai halangan(resistance ) yang lebih tinggi iaitu dikenali sebagai ' " higher head loss in piping "

Pressure dalam Pumping , biasa di kenali sebagai " Head "
1 bar =10 M head atau 14,5 psi

Pressure Tidak Mencukupi

Sebelum membuat keputusan untuk mendapatkan pam baru ,kerana pam yang sedia ada tidak dapat memberi pressure yang perlu , apakah sebab sebabnya?
A) WEAR AND TEAR
B ) ATAU SYSTEM PRESSURE TERLALU TINGGI
C) ATAU PAM DI BELI,TIDAK MEMENUH SPECIFIKASI
D) ATAU SYSTEM PROBLEm



Akan bersambung lagi

Treated Effluent Pumping -Land Disposal

Dear Oil Mill Users

Generally this application can be about 60 to 100 m3/hr pumping rate
And pressure will depend on piping distance
If the distance is short , open impeller centrifugal pumps can be used

However is the distance is 1.5 Kilometer .you may need a Two Stage Screw Pump to do the job with operating pressure of about 8 to 10 bar ,depending on the pipe diameter

Again ,I wish to highlight the importance of designing an optimum pipe diameter
A smaller diameter would mean higher operating pressure and on the other hand too big a diameter will incur higher capital cost
Work out cost of pipes over operating cost in term of power cost

Pipes are buried underground and Polypipe are being used .
If pressure is too high ,then breakages are likely to occur often and it is goiung to be very
difficult to trace the leakage
Go for as low as posiible the operating head to minimise this problem

PolyPipe is rated 10 bar and joints may be weak .When there is blockage along the pipe . a two stage pump can develop a pressure of 12 to 15 bar and hence . pipe or joints may burst
Suggest instal a pressure switch which cut off pump when the pressure exceed the limit
to protect the system

Also choose a right pressure switch .Diaphragm seal type designed for cleaning

SLUDGE DESANDING BOOSTER FEED PUMP (PALM OIL MILL)

Dear Azhar

The sludge oil to the desanding system contains high amount of sand /dirt which causes the excessive wear and tear on the pump
You are operating at 3 bar pressure and the existing pump will need about 1600 rpm which is a bit high
to do the job
Ideally ,select a pump at can operate at about 1000 rpm
Material can be Nihard or rubber lined pumps

The system pressure is 3 bar ,the OEM or Supplier of the Equipemet or system could have design the system to
be about 1.5 bar , and this simplify the operation

Initially there was some problem during commissioning stage ,but it was not the pump problem
as reported

a) complaint from mill that if valve is fully opened the Overload Relay tripped
we checked and found that the Ampheres setting was too low .therefore trip
as valve opened fully, the BHP increased .The motor rating is more than sufficient and it is fuuny that
electrical chargeman did not reliase this and ampheres of overload not set correctly

b) when valve is not fully openned .the flow was reduced at feed inlet to Desander .and hence the pressure
of only 1.7 bar

Pressure = Quantity / Area

How to determine if it is pump problem or system problem

Very often ,Engineer's mindset is that .
" NOT PERFORMING .MUST BE THE PUMP SUPPLIER PROBLEM OR OR PUMP NO GOOD "

a) First check the pump condition . If the pump condition is in order ,next
You can do a shut off Test on the pump .if pressure can be achieved at shut off ,then you can
confirm that the pumps 100 % ok

b) Check pump performance curve .see if rating done correctly for pump installed
Example ,for this duty
capacity : 20 m3/hr at 30 M head
pump Model :OB 1 1/4
pump Speed : 1800 rpm

If this is in order ,than move on the system

a) checked inlet . for any obstruction by sand /dirt accumulated at tank bottom or inlet line
b) Checked motor maximum Amps and setting amps ( your initial setting was 18.4 amps for 11 kw motor , Star Delta connection , it was later set to 22 amps )

Job Done

The overload relay resetted and valve can be fully open .pressure achieved and running in
required parameter

The problem now is high  wear & tear , suggest resize a pump to operate at lower rpm and material compatible to this operation
Another pump OB 1 1/4 -33 , can operate same duty point at 1200 rpm ,  lower speed and hence lower
wear and tear

Liquid Ring Vacuum Pump -Cavitation and Excessive Water

CAVITATION

How to Observe

When the pump cavitate ,pump will prme a rattllig noise and in worst case the pump also vibrates
On visual inspection . you will see pittings on the impeller in between the blades and edge of blades .The finger valve will also get pitted and broken

CAUSES
Usually is cuased by
1) big amont of steam being sucked in from the process
2) too high temperature of sucked gas and/or service liquid
3) too high vacuum at suction
4) service liquid with vapour pressure ( eg mixture of solvent)

Remedy

Anti cavitation valve is a good preventive measure ,but it is not a solution when the
cavitation is serious and continous, other alternative could be looked into
One of which if the Guage reading is showing about 35 m bar and below . see if can operate at lower vacuum

EXCESS OF WATER

You will notice cases of impeller blades bent or broken

Causes
1) Water is not drained when the pump stopped .the pump will start with too much water
in the pump(instal an automatic drained valve )
2) too much pressure or head of service liquid feeding(instal regulating valve for this purpose )

3) too much water or condensable steam being sucked from the process
Typical problem , for pumps used in drying process without good condensor /separator
between the pump and the process

In one soap noodle plant, the condenser is feeded water from the cooling tower
.At the water discharge area ,choked by dirt from the water system and the water
flooded the nozzle at vacuum suction line .Big amount of water is being drawn to the vacuum line

Data For Selection of Pumps : S T A M P S

The following data will be required for sizing and selecting a right pump


S > Size of pump , liters per minute or cubic meter hour(m3/hr )

T >Total Head in the system , including NPSH available

A > Application
* feed water, dosing ,transfer, mixing etc

M > Media ~name of fluid or media to be pumped
Viscosity ,SG , Temperature ,solid content ,PH etc
* these will more or less ,help us determine the type of pump to offer
* and also the material of pump construction

P > Power . the driver of pump
* electric motor .air driven or engine driven , maybe steam driven

S > Shaft sealing . mechanical seal or gland packing
* type and material of mechanical seal/packing
* require seal flush or quenching ?

SPECIFYING A REQUIREMENT

There are times where you would need extra features other than the standard features provided
by the manufacturer. It is unfair to supplier, that customer complains that I want this and not that
after the item is delivered ,As an example , we highlight the case of an electric motor

a) Protection : IP 54 or IP 55 is usually the standard protection.
b ) Insulation : Generally Class F .there are special class for furnance application.as working enviroment is of higher temperature

c) terminal box : for bigger motors of 300 kw .you may need bigger termination to suit to your cable size , do check your cable size before ordering
Or you may ask for special terminal box cover
Or location of the terminal box, left ,right or top

d) bearings : for big pulley diameter application and belt driven, and because of the big pulley is used is heavy ,you may need upgraded bearing to handle to overhung load

Or the installation of the motor does not facilitate easy greasing or maintenance work .you may opt for life lubricated bearings

Most of the cases, Engineers do not take note of these details

So far .we only come across one Engineer from the Fibreboard industry who knows exactly
his requirement .

Participation & Informations Sharing

So far,the participation in this forum has been extremely low
Engineers or Maintenance Executives are welcome to post your comments or highlight any technical
subjects on pumps and blowers
Any unusual experience in day to day opeartion of pumps and how you had overcame the problem will serve as useful informations for all of us in the industry


There is case of Vacuum pump failure due to cavitation .The problems was there and has been recurring
for a long time before one of the Experienced Engineer who join the Company decided to take a closer look
at the problem .He has identified the cuases and got it rectified.The equipment is going to perform well
for a long time
And great ,this guy simply do it on his own with some trouble shooting guide from Pump Manufacturer
Others would have been blaming the pump supplier for the failure and wants the pump supplier to
rectify the problem

Engineers should take a pro-active stance in learning.trouble shooting and problem solving
Most of the skills are acquired through practical experience .

JOB OPPORTUNITIES AT CHEMFLUID

We are an established Company and on expasnion mode .There are job opportunities
for people with keen interest to develop career in the pump industry .
The Company will provide training on this field and only those committed to long term
employment shall apply .Benefits are good incentive ,oversea trip and good working enviroment

Position : Product Manager ,Product Executive
Requirement : Diploma /Degree in Engineering
Language : Fluent in English
Working Experience: Preferably those famililar with the Chemical /Oil & Gas /Palm Oil Industry

Send your resume to :teysh@chemfluid.com

Selecting Anti Vibration Mounting Pad

There several types of anti vibrating mounting pad in the market , to suit various
operating condition and types of equipment

Check out the total equipment weight ,and work out the load per cm2
Select type and checking rating of the anti vibration pad you choose
example .it will specify max allowable load is 6 kgs/cm2

Sanitary Products in Food /Pharmaceutical Industry

What is Sanitary to the Food / Pharmaceutical Industry ?

Here are some interesting facts

1) to some . anything that does not rust and looks shiny is sanitary
even Grade 2 B stainless steel pipes used for ornamental purpose are being used in some backyard food
manufacturers

2) there are also SS316 so called sanitary pipes are being used ,without complying to certain manufacturing
requirements

3) There are few standards of piping materials to meet your process need

a) Sanitary Standard
~ surface finish of Ra 1.6 or better

b) High Clean & Tri Clover
~ Surface finish of Ra = 0.80

c) Pharma standard
~ Surface Finish internally Ra =0.4 or better

The level of cleanability in a pump or eqiupment will determine the level of compliance to FDA,and there are few levels to meet each process requirement ( will be published later )

The Health Ministry has announced years ago Certification of High Risk Food to be Mandatory
to come under Hazard Analysis & Critical Control Point

Hope serious enforcement will be carried out , although it is going to be a very
tough job to get the smaller manufacturer to comply and see the benefits

We had been busy trying to educate the our customer on the need of getting right material or pumps
for their application, but not sucessful as cost factor come first and compatibility last

Readers are welcome to contribute your findings and thoughts

Pipe Joint Breakage or Pump Casing Cracked

If you your pipe welded joint broke often or pump casing cracked ,it is likely
due to misalignment between pipe and pump casing
The pipe could be pulling to one side ,and is creating a lot of pressure on the pipework
and casing

Remove the bolts and nuts to check if the pipe flange stays parallel to the pump casing flange
Check both pump and pipe centre line , realign

This also cause vibration to pumpsets


Very often contractor weld the pipe first before alignning to the pumpset
and later will try pulling the pipe to meet the pipe pump inlet/outlet
This is very common and happening all the time here

Plant people will always blame the pumpset supplier or coupling not properly aligned

Motor Kw And Capacity

A customer once asked . with the same pump can I increase the flow with 10 hp instead of 5 hp now ?

Definitely not , but this is quite a common question as people still think bigger motor give more pressure or
capacity
The flow is determined by the pump size at given speed .Increasing the speed will increase the capacity and will required higher motor Kw .Check pump performance curve and determine what is the new duty needed
Also note the maximum speed of that pump

Air Operated Pumps

Dear Basir


Air Operated Pumps certainly have its advantages , and one is dry running capability when transferring chemicals from drum unattended . It limitations are air supply requirement , for standard pumps the maximum is 8.6 bar
You need to make careful selection , ensure material of pump is compatible to your chemical
As for occasional check valve failure , maybe due to the dirt or solids stuck in between the ballcheck
Install Strainer for the purpose

Level Control can be installed by means of float switch and solenoid valve to shut off
The shut off valve can pneumatically or electrically controlled

Pressure -- Pump Pressure or System Pressure

A Senior Engineer asked me sometime ago ,why the pressure gauge only show 3 bar but you said your pump can go maximum 10 Bar ?
The gear pump is was for lubricating bearings with an open end outlet ,check and found the flow is in order .I tried explaining to him the system pressure is 3 bar ,therefore the working pressure is 3 bar unless the discharge line is blocked or there is obstruction . A shut off test was done ,and the pressure gauge registered 10 bar easily .A lot of explaining was done but he did not want to listen as he feel that he knows better . I just took back my pump

After that .I was told he get another 2 or 3 pumps from other suppliers and encountered the same problem .This is one of the common problems we always have to deal with
It is a simple issue ,unless people listen

Pump Selection by Software

There is an increasing use of software to size and select pumps , but user
should verify the pump selected against the operating condition such as media characteristic
An example , a Lobe pump was selected and designed to run at approx 750 rpm for liquid detergent .The pump can perform, but the product is shear sensitive and it is going to create a lot of bubbles at the storage tank

Therefore . the user or engineer should take this into consideration and determine what is the maximum operating speed for the media.Experience plays a part when come to selection of pumps

Motor Overloading

Dear Chong

Motor Overloading when valve fully open
Check the performance curve and see if the Impeller diameter and Motor Kw
is in order .Otherwise trim the impeller to correct diameter ,bearing in mind that it must meet your duty
point required

When replacing a different size of pump, be sure to compare the duty point of both the pumps
Otherwise , you may have an oversized or undersized problem

When Increasing the capacity of pump . re calculate the delivery head
See earlier posting on this matter

Upgrading of Pumps

Very often when upgrading of pump to higher capacity .the piping system is not taken into consideration . Higher capacity for the same piping diameter would mean greater system pressure
If the piping length is very long . the system pressure should be recalculated to determine the new pumping head before selecting the pump .Suction line,the NPSH avialable must also be looked into

Otherwise .the new pump is not likely to perform as rated