Low discharge pressure can be caused only by loss of flow.  Pump discharge pressure is caused ONLY by the system's resistance to the flow provided by the pump.  Either the pump is not providing the flow expected, or the system is not offering expected resistance to that flow.  It is possible that flow into the pump is being restricted (cavitation or suction starvation).  This phenomenon is usually accompanied by noise and vibration.  Or, it could be that the pump is not producing its rated flow (pump worn or damaged), or that the pump flow is bypassing rather than being delivered into the system as intended (open, improperly set, damaged or worn discharge system valve).  If the pump is relatively new and not being used in abrasive service, it is most probable that discharge flow is bypassing.  The most likely paths for such unwanted bypass are the system pressure relief valve (sometimes built into the pump), a bypass pressure regulator leaking (typical of a fuel oil burner system), an inadvertently open bypass valve, or any of these valves having worn valve seats, incompletely closed stems, incorrect signal control or broken springs.

Many pumps can receive a quick, though incomplete, inspection in place without disturbing piping or pump alignment.  If the pump does not turn over by hand or with a little leverage assistance and in a smooth manner, the pump itself may be the problem.  If one or more of the pumping elements can be visually inspected without major tear down or pump removal, do so.  Enough wear to cause a pressure reduction (flow loss) should be readily visible.

It is sometimes difficult to determine if a valve is bypassing when it shouldn't, especially if the valve is built into the pump.  It is probably best to remove the valve, do a partial valve dis-assembly and examine the mating valve seat surfaces or seat seals for wear or damage.  Check any spring to be sure it is not broken.  Work the valve mechanism manually if possibly to detect any binding or galling.

If the problem has still not been identified, be sure the pump river speed is being achieved and that the pump shaft is actually rotating at is correct speed.  These conditions must be met, especially in a new system start up.

There are many factors when choosing a pump - pressure, flow, liquid properties, accuracy, shear and power requirements  to name a few.  Imo pump  recently introduced one of the most complete pump specification sheets  on the market.  If you're not sure which pump type you need, start here and we'll work with you to choose the best product for your application.

Today, I'd like to provide with readers a quick reference guide on when to use the products that Colfax Fluid Handling offers.  This summary is referenced from the 2008 American National Standard for Rotary Pump types and Nomenclature, Hydraulic Institute.  Note, a timed multiple screw pump is also known as a two screw pump and an untimed multiple screw pump is also known as a three screw pump.

As always, a thorough discussion with an application engineer is recommended if your application falls outside of these parameters.

There's a lot more to it then this and we're encouraging readers to contact us and discuss a lunch and learn session.  What's better than a free lunch and a little education?

Why is the right design important or what are some of the hazards users might experience when pumping ammonium nitrate?

• Deadhead pumping which is caused by cooled down emulsion explosive forming a plug or by a foreign object
• Dry pumping which generates excessive heat and may result in ignition of explosive residue

These are just some of the reasons the Allweiler branded pumps are the pump of choice.  Allweiler pumps applied in this application are intrinsically safe and have met (or can meet) the necessary hazard operation reviews required.

Download your copy of our progressing cavity pump brochure,  fill out the application data sheet and get the right pump for your application or contact us to learn how we can help.

Rapid pump wear is caused by either abrasives in the liquid or operation under conditions for which the pump is not suitable, such as excessively low viscosity or excessively higher pressure or temperature.  If abrasives are a normal condition of the pumping application, as in slurry pumping, then pump wear will be a fact of life, and the best that can be done will include pump and drive speed selection that provides the best economic evaluation over the pump life cycle.  While requiring bigger displacement and more expensive pumps, slower operation on abrasive service often pays back far beyond the initial purchase cost differential.

Wear due to abrasives in the liquid is a function of speed raise to a power usually betwen 2 and 3.  If the abrasives are deliberately introduced, as when fuel oil additives intended to reduce boiler corrosion are brought into a system, they should be injected downstream of any liquid recirculation to insure that they do not go through the pump.  Obviously, if abrasive foreign material is not supposed to be present, strainers or filters should be employed wherever possible and practical.

Rapid wear is sometimes not wear in the sense of a non-durable pump, but rather a catastrophic pump failure that occurs very quickly.  Looking at the pump internal parts alone can frequently not provide much help in setting a direction to search.  So, it is important to know what was occurring in the time period immediately preceding the detection problem.

Often, pump manufacturers offer a checklist designed to help you understand potential causes to failure. Contact your supplier today to discuss your issue and what supporting information they have available.

I'm also pleased to announce that our IMO pump brand has an updated Application Data Sheet.   The data included in the online tool enables our engineers to answer your questions and projects request quickly and accurately.  Moreover, you can consider products from the entire Colfax product portfolio.

The quality of leads generated at the show was, however, solid and the Colfax team was fortunate to talk with people who -

• Had problems with water in their lubrication Oil (recommend the ThermoJet or PurLube)
• Was interested in pumping sulfuric acid within the environmental system of his plant (recommended the Zenith metering pump)
• Was interested in using a progressing cavity pump in a vertical configuration to save space in his sump (recommended the Allweiler branded progressing cavity or Emtec pump)
• Needed  to understand how to size three screw pumps for a fuel oil plant that they were building in the Middle East (recommended the IMO or Allweiler branded three screw pump)

These were only some of the applications that we discussed with show attendees.  These leads also show the diversity and flexibility of the Colfax portfolio and the global coverage that we offer our customers.

Finally, we always welcome the opportunity to conduct a lunch and learn seminar for your associates.  We offer topics such as the basics of centrifugal vs. positive displacement pumps, design and considerations for lubrication oil systems and three and two screw pumps benefits and design considerations.  If you're interested, let me know.

Contact us if you're interested in designing a better system.

Baric is well known as a designer and manufacturer of unique packaged units for the rotating machinery industry. The Power Gen industry, however, primarily uses pre-engineered or “build to print” packages. Can you provide some example of your ability to showcase Baric’s design skills in the Power Gen market?

Yes, there are several examples. In fact, we have a design contract to design a skid package for a particular sized turbine for a major global Power Gen supplier.

One of our best examples, however, was a project in which we provided Lube Oil Systems (LOS) for 50Hz and 60Hz turbo-gen sets. It was essentially a “build to print” contract, but we identified a number of improvements that could be made on the systems, which we relayed to the customer.

We’re quite proud of our ability to add value to a customer’s projects by drawing on experience and know-how.

Was the customer interest in finding out about the improvements?

Absolutely. We were invited to participate in a number of seminars – mini-Kaizens, actually, with their design team.

What was the focus of the seminars?

There were essentially three considerations:

• Review and update the global specifications for the lubrication oil system
• A detailed review of main sub-supplied equipment, such as pumps, motors and control valves
• The physical layout of the lubrication oil system

What were the biggest challenges the seminars presented?

The first two were fairly straightforward as the assembled teams worked through the original global specifications. We discussed each element in detail – from material selections of reservoirs and piping to potential suppliers for the main buy outs. We then created a revised final version based on a combination of best practices, shared field experiences and sub-supplier evaluation.

The real challenge came in the design of the LOS itself. Both the 50Hz and 60Hz Turbo-Gen sets had to have the same physical footprint. Site interface points had to be located in the same places. Multiple Lube Oil Cooler options had to be designed without changing the footprint. This included the remote air cooled heat exchanger, plus a single plate & frame water cooled heat exchanger LOS and a dual (duty and standby) plate & frame water cooled heat exchanger, both mounted on the LOS. Both required European (CE) and North American instrumentation installation, as well as AC and DC motor installation. Working together, the customer’s team and the Baric team were able to solve these issues.

Do you think the exercise was a success?

Most definitely. By achieving the design brief as describe above, it gave the customer the option to provide the LOS as a stock order item, based on local requirements, for any area of the world in which they marketed. But for us, the biggest validation was the number of contracts we received by using this design, supplying machinery in Asia, the Americas and Europe.

Excessive noise and/or vibration is typically a symptom of cavitation, suction starvation or excessive gas in the liquid.  This is especially true if the discharge pressure is fluctuating or pulsating.  Mechanical causes of noise and vibration include shaft misalignment, loose couplings, loose pump and /or driver mounting hardware, and worn or damaged driver or pump bearings.

Also, pump valves can also vibrate noisily.  Especially on the discharge side of the pump, valves can sometimes go into a hydraulic vibration mode caused by operating pressure, flow rate and the valve design.  Resetting or a  change in an internal valve component is usually sufficient to solve the problem, but we recommend that you consult your valve supplier to determine the best course of action.

Check out the Colfax SMART Sense Pulse for a quick, efficient monitoring device for your screw or rotary pump system(s).

If you are able to visit, let us know what you think.  We look forward to hearing from you.

Excessive power consumption can be caused by either mechanical or hydraulic problems.  For rotary pumps, the pump power requirements are directly proportional to pressure and speed.  If either has increased, the required input power will increase.  Power required will also increase if the fluid viscosity has increased.  This can happen if the liquid has been changed to something new or the liquid operating temperature has been reduced.  Some liquids (grease, for example) are shear sensitive and can become more or less viscous with shear (pumping action) as well as undergo permanent viscosity change from shear over time.

Mechanical causes of high power usage include bearing wear out, pumping elements rubbing (a situation that can lead to pump failure), very bad shaft alignments and poor pulley alignments for belt drive arrangements.