We’ve all had our share of maintenance costs, downtime, and performance issues with our pumps in the past and no doubt we expect them to occur again tomorrow.
It’s a symptom of a larger problem. The idea that you can just put a set of parts together and hope that they will deliver the outcome you need.
However, that doesn’t need to be the case.
A different way of looking at the purchase of pumps and their accessories as well as how the system is designed, constructed and integrated offers a way to break through the old model of buying and assembling your own pump systems and have them built in a way that provides the performance required with a lower cost of ownership and more up time.
With many capital investments the impact of an oversight or poor choice can be felt for years to come. Not too many organizations have the discretionary budget to reinstall a pumping station in order to bring down the total cost of ownership by a few percentage points after it is discovered that the pumps they installed were cheaper to purchase but more expensive to run compared to the alternative.
In the end it is a failure to look at the system as a whole rather than by assessing the purchase as a set of independent parts.
Operating Costs. Between 40% and 60% of the total cost of ownership of a pump will be maintenance and power costs. The ongoing operating and maintenance costs can be even higher if the system isn’t built to keep operating costs to a minimum.
Many construction contractors might use cheaper components in order to maximize their profits, but that will leave the owner with a higher than necessary operating costs.
For the client, this means their interests are in direct opposition to the contractors and leaving them to design and commission the pump system can leave them footing a larger bill over the life of the pump.
Many of the supporting technologies such as ‘smart’ controls and variable frequency drives require some knowhow to integrate all components to ensure the most efficient system design. The integration is often easy when you the builder is experienced with the components and knows how to get them to work together – which comes from the experience of assembling many pump systems.
When you are only assembling a few pump systems a year this experience can be hard to come by – which might result in short cuts, scope changes or the project being abandoned and reverting to a less efficient build because something similar worked in the past.
Purchasing an integrated system gives the end user the peace of mind that they are buying a guaranteed result and not just a pile of parts that they need to assemble before they can get any mileage from their investment.
This will save time at installation testing and commissioning.
Warranty Concerns When you assemble a system yourself, there is only a warranty on then individual parts. When you get a custom built, tested and commissioned pump skid there is a warranty on the whole unit.
In scenario one your maintenance team might have to make multiple calls in order to get the ownership of the fault and a replacement part arranged. In the second, they make one phone call to the package builder and the builder will diagnose the problem and then fix it.
Piping design and layout can affect fluid flow. Assessing the piping system for blockages and choke points and rectifying any major obstructions can Increase friction losses and result in additional work that will pump will need to do.
As part of any specification it is extremely important that your systems designer create a performance curve for your system and inspect the piping after installation.
These can be simple and low-cost fixes that reduce the amount of capital that needs to be ‘sunk’ into your pump system.
A systems approach to pumps simply means looking at your pumps as an integrated system rather than a series of parts that happen to be connected to each other.
It means making sure that each component in the system is working to achieve an optimal result. Identifying any bottlenecks and working with them or working to eliminate them.
Many pump suppliers don’t take the time to be sure that you’ll get the performance you need with the lowest possible investment.
Care needs to be taken to understand a client’s needs and then design solutions that meet those specific needs rather than taking a one size fits all approach or just recommending the cheapest pump units that will get the job done.
Sometimes buying a cheap unit is the best bet – for example in low margin industries where the wear and tear on the pump is extreme – running the cheapest possible pump can make sense.
Pump systems should be in effect, reverse engineered out of the needs of the particular site and the client. What flow? How much redundancy? How do we best match supply and demand? What do we need to do about noise?
By switching to a supplier who can design, specify and build your pump systems for you, the end client can streamline their construction process while guaranteeing they will get the performance that they need for the application.
The process for specifying a pump system always follows a process like this.
Before worrying about the specific flow or the pressure. the following general design considerations need to be assessed.
Details of the Application: Does the application require constant flow and pressure or do you have variable flow or pressure? Is it a continuous or intermittent service? Is it mission critical? Do you need 99% uptime or better? What redundancy exists? What redundancy do we need to meet your required uptime?
What are the Space Requirements? How much space do you have in the mechanical room? When space is tight, it will force the selection of smaller pumps or a vertical mount pump.
What is the Quality of Your Power Source? In many parts of Georgia at the end of the grid, you may not get 460V, or may have voltage that fluctuates all the time. Depending on how “clean” your power is, certain devices will need to be used in the control panel to stabilize the power feeding the motor.
What is Your Life Expectancy for the Pump? Is this a temporary service? A critical service? What is the life that you expect to get out of this pump? The pump we’d recommend if you need a pump for a service lasting 3 months is different to the pump we’d recommend if you want it to run for 20 plus years.
Energy Efficiency: When motor size exceeds 50hp reducing electricity consumption by 5-15% can save you thousands of dollars a year, slashing total cost of ownership. Remember your affinity laws: The break horsepower increases to the cube of the speed. With management often having a ‘green vision,’ energy efficiency always needs to be discussed on even the smallest pumps.
Pipes and Fittings: A detailed discussion on pipe sizing selection will require a lot more coverage than possible in this article. In brief, the pump material will need to be determined based on the fluid being pumped, the flow and pressure requirement.
Usually, the pipe is sized so that the velocity does not exceed 10FPS. Otherwise, you will have excessive losses in the pipe that will result in higher pump BHP and perhaps a larger motor.
At a minimum, the following information is required in order to get a proper pump selection:
Flow (GPM or L/S, M3/Hr)
Specific Gravity and viscosity
TDH (FT, M, KPa)
Horizontal or vertical installation
Fluid name and temperature
Materials of construction
Pump speed
Motor data
This will allow your pump systems builder to assess your options and select a pump or pumps that best meet your design criteria. A good design specification will
• Select the pump duty point to be closest to the best efficiency point on the curve.
• Not select a pump to operate continuously below the minimum flow design of the pump.
• Not select a pump to operate at more than 120% of best efficiency point on the curve. In both cases, the pump will be operating outside its design hydraulics and doing so will cause the pump to cavitate and ultimately fail.
• Add 10% to the pump head when selecting the pump size. This is to allow for motor speed variances, excessive valve losses, old pump patterns and inaccurate curves. If this forces a larger motor size, increase the impeller diameter as much as possible to stay with the selected motor hp.
• Determine the maximum BHP based on non-overloading requirements over the entire range of the curve.
• If you have an application where the pump can possibly run dry for an extended period of time, use a dry run protection device. This device will automatically shut down the pump before any severe damage occurs.
Motors should be sized based on the pump brake horsepower (BHP). Once the pump BHP is determined for the entire range over the pump curve, the next larger size motor should be selected.
For example, if the maximum BHP is 17.5, then a 20HP should be selected.
There are other factors that should be taken into consideration when selecting a motor. These include:
• Type of motor
• Application
• HP and RPM
• Enclosure
• Class of insulation
• Voltage, phase and frequency
• Starting method
• Ambient temperature
• Altitude (site location)
• Any special accessories for special conditions, like space heaters, thermistors, RTD’s,
etc.
The following accessories will not necessarily be specified as part of every system but most of them will be on most well-designed systems so it is important to understand how they can help improve performance and reliability.
Check Valves
In almost all applications, a check valve (or non-return) valve must be used on the pump discharge.
This will protect the pump against backflow from the system. They can be either fast acting or slow acting depending on what the application requires. They are specified based on the pressure, temperature and flow requirement of the application.
Pressure Reducing Valves
If you do have such an application where the pump is operating at 100% and there is no way to change the flow/head of the pump then the use of a pressure reducing valve is recommended.
This will allow you to set the discharge pressure to a specific point no matter what the pump discharge pressure is. They are available in both globe and angle configurations, with flanged connections in size 1.5” and larger.
Isolating Valves
Isolating valves must be used upstream and downstream of the pump in order to isolate the pump when maintenance is required. The three most commonly used isolating valves are Gate, Butterfly and Ball valves.
Ball valves are most commonly used with small piping, 2” or smaller. Gate valves are mostly used on water application or process where simple open/closed operation is required.
The butterfly valve is the most common isolating valve used on water and process applications as they offer a 100% shutoff feature, are good in throttling applications and have the ability to be controlled by pneumatic or electric controllers for automated service.
Instrumentation and Controls
The type and sophistication of the controls installed, and the monitoring needs of the client will influence what is specified for a pump monitoring systems and controls.
Pressure: Every pump system needs to measure pressure on both the suction side and the discharge side. Without a pressure gauge, there is no way to determine what pressure the pump is delivering.
Temperature: If the application is a temperature sensitive or temperature dependent application, then a temperature gauge must be used on the pump or on the discharge pipe very close to the pump.
Pressure Control: If the application is a simple on-off operation, then a pressure switch can be used. The pressure switch can be set with a “low” set point and a “high” set point that will allow it to activate and deactivate. However, if a more accurate reading is required a pressure transducer can be used that can send a signal to the controller for various process changes based on the pressure.
Flow Control: If the application requires a precise flow control or has a variable flow demand, then a flow meter can be used to send constant data to the controller that will allow the user to change the pump setting accordingly.
Control Panel: A control panel will house all the electrical components and sometimes other instruments like the variable frequency drives and pressure transducers.
They can be as simple as an on-off starter panel or a very complex panel that houses VFD’s and communication modules to communicate with the building management system. Usually the electrical engineer will design the controller based on the equipment that it is controlling and how it will integrate with the overall system process.
Moving to a systems approach for your pumps will help you and your plant to achieve the following:
Drive Down Operating Costs
Around 30% of a centrifugal pump’s TCO is energy consumption (purchase is about 10%). Repairs and maintenance runs at about 20%. Minimizing power consumption should be a chief goal in your purchasing process. It will pay off over the life of the pump.
A systems approach to purchasing will be your best bet for getting the lowest possible power consumption because as the pump system is designed, choices about pump model and accessories can be made that will help to keep the power consumption as low as possible given your current situation.
Meeting Application Performance Goals
When you are making an investment in a pump, it’s worth remembering that you don’t want a pump exactly. You want a flow rate of liquid at a specified pressure.
A key to success is being sure that the pump selected can actually meet the performance through a system wide analysis.
Pipe material and layout need to be analyzed before a pump system can be specified.
Delivering the specified output can mean productivity gains in a production setting which turns into increased profit. A pre-built pump system can be tested before shipment which will guarantee the specified criteria is met.
Managing Downtime AND Preventing Breakdowns
When purchasing pumps, you have two main ways to prevent breakdowns. The first is select the best pump for the job which will minimize frequency of breakdowns and outages.
The second way is to make sure that adequate redundancy is available so that when a breakdown does occur then it doesn’t cause the operation to grind to a complete halt.
Taking time to understand your goals and what is acceptable allows the best decision to be made to create redundancy. This might range from having redundant capacity installed, to having a replacement pump on the shelf ready to go, to having a replacement pump at your supplier warehouse a, to just accepting the lead time to order a new one from a supplier when it does break down.
That way the purchaser knows what they are in for in advance and to plan accordingly.
Plug and Play Pump Assemblies Ordering Capability
It takes specialized knowledge to build fully integrated pump assemblies. There is a lot involved: getting components to integrate and work together, testing to make sure they are working as specified – it can be hard work for an overwhelmed maintenance team who are not ‘elbows deep’ in this work every day.
The overall objective is to minimize the friction losses to ensure the lowest possible energy consumption and maximize the system life by sizing and selecting the best materials and pipe layout possible for the application and the location.
This is not always as simple as it sounds. Then, there is the task of getting the monitoring equipment integrate with the control panel. Then programming the control panel so that the pump assembly so that the client can just connect the supply and discharge pipes and press ‘on.’
In the end this investment can help to keep construction on schedule, avoid late payments to the builder and seeing that the project is delivered on schedule which in turn means production which starts or resumes on time.
Based on 150 years of engineering experience at Pye-Barker, here are some of the top considerations for selecting a pump systems provider – they should help you evaluate your vendor and get you’re the best possible result:
1. Who is going to be designing the system for us?
2. How much experience do they have designing similar systems?
3. What will my projected total cost of ownership be?
4. Can it be made better?
5. In situations where space is at a premium: Is the system occupying the smallest footprint possible?
6. Who is going to be building this system for us?
7. How much experience do they have building, testing and commissioning systems like this?
8. What are our costs if the project is delayed?
9. What is the cost of lost production if the project is delayed?
10. Who is going to do the maintenance in the long term?
11. Who is responsible for the system long term?
12. Who will I be dealing with if there are warranty problems? (Do I want to have a single contact for the whole system or will I be chasing component manufacturers?)
Pye-Barker can advise you on the design, specification, provide all the parts for your pump system, install them and maintain them for you. With 150 years of fluid handling and compressed air engineering experience. There isn’t an application we haven’t had direct experience with already and worked out how to custom design and build a system for it.
Pye Barker specializes in managing the entire process of designing, building and repairing pump systems so that their clients never have to worry about them during any part of their lifecycle.
All Pye-Barker designs that are built and installed by Pye-Barker are guaranteed to get the specified performance, otherwise Pye-Barker will guarantee to keep working with you until your pump system works as specified even if it means installing a whole new pump.
If you are planning to build, upgrade or add a pump system, the first step to getting the right performance is a no-cost, no-obligation “Design Needs Assessment.” To schedule your “Design Needs Assessment” call 404-363-6000, or send an email to sales@pyebarker.com or go to https://pyebarker.com/contact/#quote
This post was brought to you by Pye-Barker Engineered Solutions in partnership with IndustryNet.
Have industry knowledge like this to share? IndustryNet can help you reach the right audience. Learn more about our marketing solutions.
Follow IndustryNet on Google News