Pumping World News Blog

Is Your Trailer Pump Impeller Installed Correctly?

Posted by Elizabeth Kaiser on Wed, Feb 08, 2012 @ 08:02 AM

By Travis Stroh, SRS Crisafulli Applications Specialist

Over the years trailer pumps get modified, parts get replaced and sometimes one of those parts is a new impeller. Here are some tips for inspection, removal and installation to make sure your impeller gets installed correctly.

IMPELLER ROTATION AND ASSEMBLY INSPECTION
To avoid expensive repairs and downtime, take a minute and verify that your impeller is rotating in the right direction. Problems you might see if your impeller is installed backwards:

  • Pump does not deliver water
  • Insufficient flow delivered
  • Insufficient pressure developed
  • Pump requires excessive power

backwards impeller resized 600An impeller installed backwards

The impeller in this picture was installed backwards. When looking at the impeller from the back of the pump, make sure the blades are backhanding the water and not cupping it.

Operation of the pump with the impeller rotating in the wrong direction will result in greatly reduced performance and increased wear.  Check the impeller assembly to make sure the vanes curve backward from the hub out in direction of rotation as shown in the figure below.  If incorrect, the impeller is installed backwards and must be reversed on the shaft. 

impeller drawing resized 600

Warning: Before performing maintenance, disconnect the power source and take any necessary precautions to assure that power to the pump will not be engaged while work is being done.

Note:  Ridding the shaft of paint with paint remover, cleaning and sanding the shaft with an emery cloth, and oiling the shaft may assist in impeller removal and installation.

IMPELLER REMOVAL

  1. Remove the nuts from the bolts on the casing back door (6-18 nuts depending on pump size).
  2. If water-lubricated bearings are used, no loosening of set screws on the bearing eccentric collar is necessary prior to back door removal.  This type of bearing is assembled to slide over the shaft.  However, if sealed bearings are used, loosening of the set screws on the bearing eccentric collar is necessary to allow the bearing to slide over the shaft.  (See note below.)
  3. Remove the casing back door.  Mark the casing and casing back door so reassembly will be to the same bolt pattern.  Tapping the back door around the bolts may be necessary for removal due to adhesive glue or gasket holding the back door to the casing.
  4. Loosen the impeller hub set screws.
  5. Slide the impeller off of the shaft.
  6. Remove key stock from shaft and inspect for wear or damage.

IMPELLER INSTALLATION

  1. Clean the impeller hub and shaft to assure both surfaces are clean, smooth, and free of paint, burrs, sharp gouges, etc.
  2. Place key stock in the shaft keyway
  3. Apply anti-seize lubricant to shaft and key.
  4. Slide impeller onto the shaft and over the keyway.  Check the impeller for correct vane curvature as discussed above.
  5. Center the impeller in the volute. The impeller is set equally spaced between front and back cases of pump to allow it to spin free.  The tolerance between inside the pump case and impeller is generally about 1/8".
  6. Block the impeller to prevent rotation.
  7. Tighten the impeller set screws which hold the impeller to the shaft.  Do not lubricate the set screws.
  8. Slide the back door and bearing over the shaft.  Align the back door to the proper bolt holes and install two or three nuts.  Turn the shaft and check the
  9. If the impeller is rubbing the casing, remove back door, adjust the impeller, reassemble and recheck for proper clearances.
  10. Once the impeller is centered properly, slide the back door a few inches away from the casing and spread gasket cement around the back door where contact is made with the casing.  This will prevent leakage from the pump and will improve overall performance.
  11. Bolt the back door to the casing.
  12. If water lubricated bearings are used, no set screw adjustment is needed.  Tighten the eccentric lock collar to the bearing by use of a punch and then tightened to the shaft by set screws.
  13. Remove any impeller blocking devices.  Turn the shaft to check alignment; shaft should turn freely by hand.  If binding of the shaft occurs, adjust bearings and recheck alignment.

 

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Topics: crisafulli, srs crisafulli, Product Information, agriculture, pumps and power units, Replacement Part, Spare Parts

Trailer Pump Operation and Performance (Part 3 of 3)

Posted by Elizabeth Kaiser on Wed, Dec 28, 2011 @ 09:12 AM

By Isaiah Helm, SRS Crisafulli Applications Engineer

SYSTEM CURVES

Just as a plot can be made of pump performance, a graph can be made of the resistance to flow of the piping system through which the pump must drive the fluid.  Using the same head-flow coordinates as the pump performance curve, the figures below can be created.  The curve in Figure 1 represents a system in which there is no static head.  The curve in Figure 2 shows the loss curve displaced upward an amount equal to the static head.

System Curve 1Figure 1: a system in which there is no static head

System Curve 2Figure 2:  the loss curve displaced upward an amount equal to the static head

After a pump is installed on the basis of a certain head and capacity requirement, it may be desired to vary the pump's performance.  A controllable restriction such as a valve can be placed in the discharge line to vary the system friction loss (dynamic head).  The operating point of the pump may then be moved along its performance curve by opening or closing the valve.  Figure 3 below demonstrates the response to changes in head.

System Curve 3
Figure 3: the response to changes in head

In most systems, the static head will vary as a pond is drained or a river level rises and falls.  As the vertical distance from intake to discharge increases, the static head also increases, effectively raising the system curve.  The system head is then represented as a pair of parallel curves intercepting the performance curve, as shown in the figure 4 below.  These two curves determine through what range of capacity and total head the pump will be expected to operate.

System Curve 4
Figure 4:  parallel curves intercepting the performance curve

An example system curve is shown below for a 4-inch L-series pump.  The static head (lift) is 7 feet, and it is pumping through 50 feet of rubber discharge tubing.  The TDH increases from the base value of 7 feet as the flow increases and more energy is lost to friction between the water and discharge tubing.  If the impeller is spun at 540 RPM, the intersection of the 540 RPM curve and the system curve designates the expected operating point.  In this example situation, the pump  will produce nearly 600 gallons per minute out the end of the 50 foot discharge hose.

System Curve 5

 

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Topics: crisafulli, srs crisafulli, Product Information, pumps and power units

Trailer Pump Operation and Performance (Part 2 of 3)

Posted by Elizabeth Kaiser on Wed, Dec 21, 2011 @ 11:12 AM

By Isaiah Helm, SRS Crisafulli Applications Engineer

PERFORMANCE CURVES

Performance curves are used to predict a pump's flow as a function of total dynamic head, impeller diameter, and rotational speed.

Total dynamic head (TDH) is measured in feet and equals the total of a system's static and dynamic heads.  Static head is the vertical distance the fluid is lifted, and does not change the flow.  Dynamic head represents the potential head that is lost to friction between the fluid and the piping system, and increases with flow.

pump performance curve

Head is equivalent to pressure, in that head in feet divided by 2.3114 equals the pressure at the pump in pounds per square inch. 

The red lines on the performance curve above show that a 4 inch L-series trailer pump with a 16 inch diameter impeller spinning at 540 RPM will produce 600 GPM at a system TDH of 19 feet.

 

Request a consultation with one of our Applications Engineers/Specialists.

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Topics: crisafulli, Product Information, pumps and power units

Trailer Pump Operation and Performance (Part 1 of 3)

Posted by Elizabeth Kaiser on Thu, Dec 15, 2011 @ 10:12 AM

By Isaiah Helm, SRS Crisafulli Applications Engineer

Crisafulli pumps are naturally robust, and capable of handling a variety of unscreened water-borne debris and slurry mixtures.  The following table lists the maximum sizes of spherical solids each model can pass without clogging.

 

Impeller (in)

Solid Size (in)

4

1-1/4

6

1-3/4

8

2-1/4

10

3

12

3-3/4

16

5-1/4

24

7-1/2

 

Occasionally the pump's speed will have to be changed to get more or less flow and pressure.  A small change in speed can result in a large change in power required.  Increasing the speed by a factor of 2 increases the horsepower requirement by a factor of 8 (2 cubed).  This can be estimated with the Affinity Laws below, taken from the Cameron Hydraulic Data Book (Flowserve Corporation):

Crisafulli Pump Curve 

H = Heads in feet

Q = Capacities in gallons per minute

S = Speeds in revolutions per minute

BHP = Brake Horsepower

Subscript 1 is for original design conditions.

Subscript 2 is for new design conditions.

Note: The Affinity Laws lose accuracy with larger speed variations.  Consult with the factory when considering speed changes of more than 20%.

A pump's impeller may need to be changed in order to get more flow and pressure or to require less horsepower with resulting less flow and pressure.  SRS Crisafulli offers up to three different impeller styles for each pump size.  They are referred to as Regular Lift, Intermediate Lift, and High Lift impellers.  The difference is their diameter.  For a change from a 16 inch Regular Lift impeller to a 21 inch High Lift impeller, the flow would increase by a factor of 1.3, the pressure by a factor of 1.7, and the power by a factor of 2.2.  This effectively doubles the horsepower requirements without changing the pump speed.

While Affinity Laws exist for diameter changes, they are only accurate for small changes of 5%-10%.  The best way to understand this relationship is to view the pump performance curves for the various impellers offered by SRS Crisafulli.

 

Request a consultation with one of our Applications Engineers/Specialists.

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Topics: crisafulli, srs crisafulli, Product Information, agriculture, slurry trailer pumps, Equipment Dealers, pumps and power units, mining, Replacement Part

Lake Dorothy Hydroelectric Dam Completion Benefits Alaska Residents

Posted by Elizabeth Kaiser on Wed, Nov 16, 2011 @ 09:11 AM

The Lake Dorothy Hydroelectric Project, located near Juneau Alaska, was begun in 2006 and completed in 2010.  Karl Vander, of North Pacific Erectors, was the Project Manager.  North Pacific Erectors, a General Contractor for commercial and industrial construction, provided all construction trade labor, materials and expertise in the design-build hydroelectric development.

Lake Dorothy      Photo Credit:  North Pacific Erectors, Inc.

We recently asked Karl to describe the Lake Dorothy hydroelectric dam.  "Lake Dorothy is a 15 megawatt hydro power plant that is at sea level.  The water is brought to the project via a penstock (5' diameter metal pipe) from a lake tap (a tunnel to the bottom of Lake Dorothy.)  That water is controlled by a 5' diameter valve and a 1,100' piece of penstock.  The water is spilled out of the tunnel and down existing creeks through Louie Lake and Bart Lake.  From that point there is an intake structure for the 5' pipe that takes it the rest of the way to the power plant."

Lake Dorothy Photo Credit:  Alaska Electric Light and Power's "Lake Dorothy The Cost of Generation" presentation

Karl added, "The project is complete and has the capability, with another tunnel and two more turbines added, to produce another 15 megawatts in the future.  The power is owned by Alaska Electric Light and Power, the electrical utility in Juneau and sold to Juneau residents.  Lake Dorothy compliments the 70 megawatt hydro plant at Snettisham and three other 3 megawatt plants that supply Juneau."

In a presentation by Tim McLeod, President of Alaska Electric Light and Power, we saw a photo history of the project, including a hair-raising shot of a treacherous road being cut from the mountain side.  This made us question "how the heck did they get all the equipment to such a remote location?"

Lake Dorothy
Photo Credit:  Alaska Electric Light and Power's "Lake Dorothy The Cost of Generation" presentation

Karl explained "All the materials and equipment to build the Lake Dorothy project were barged in and the dirt crew that built the road lived there in a camp.   Our crew took a 40' boat to and from the job 20 miles everyday."

 

Read and see a photo history in Tim McLeod's PDF presentation.

Read Alaska Electric Light and Power Company's description of The Lake Dorothy Project.

Read the North Pacific Erectors, Inc. Lake Dorothy Hydroelectric Project Information.

 

Have a project you are working on that you think our SRS Crisafulli specialists can help you with?  Contact us today! Be one of the first to mention this article and we'll send you an SRS Crisafulli hat.

Topics: crisafulli, pumps and power units, Articles

SRS Crisafulli Saves the Day

Posted by Elizabeth Kaiser on Thu, Sep 08, 2011 @ 08:09 AM

On August 12, 2011 Maureen Lundman, SRS Crisafulli Sales Manager, received an email from SRS Crisafulli customer Mike Henningsen, of Henningsen Construction, Inc. Mike had a dramatic story to tell about how our pump saved his business.  Here are his comments:

Maureen,

Just thought you might like to hear an interesting story about one of your 12" trailer pumps.

We have an asphalt plant north of Council Bluffs, IA that since mid June has been and continues to be surrounded by the Missouri river. We built an 8' to 12' dike around the plant and lined the outside with plastic.

application for SRS Crisafulli trailer pump
Dike lined with plastic

The dike has held out the river for two months, and we expect the 8' to 10' of water surrounding the plant to be there for another month and a half. Oh by the way we are 4 miles from the main river channel. We have seepage around the inside of the milled asphalt dike.


SRS Crisafulli PTO Trailer Pump
SRS Crisafulli trailer pump in action

That water is being pumped out continuously by a tractor turning your (knock on wood) great pump.

We estimate the pump has run 1400 hours straight - the end is not in sight.

tractor for SRS Crisafullitrailer pump
SRS Crisafulli PTO Trailer Pump

We are hopeful tractor and pump keep doing their dutiful job.

 

Dike pumped by SRS Crisafulli trailer pump
Successfully pumped dike

Your pump has worked flawlessly. Thank you!

 

For 5 decades SRS Crisafulli has been an integral part in serving customers whose land, businesses, livestock, and peace of mind have been saved with our flood management pumps throughout U.S. and Canada. 

 

Visit our website to read more testimonials about using SRS Crisafulli Vertical Pumps for flood and stormwater management.

Read how SRS Crisafulli Trailer Pumps were used for flood and stormwater management.

Read how the U.S. Army Corps of Engineers managed flooding in Idaho with an SRS Crisafulli PTO trailer pump.

Read how an SRS Crisafulli Vertical Pumps solved a flooding problem in the Red River Valley of the North.

Do you have a story to tell about one of our products?  Submit your own testimonial.

 

Click the Play icon to watch trailer pump video.

 

 

 

 

Topics: crisafulli, srs crisafulli, pumps and power units, vertical pump

The Importance of Mechanical Seals on Pumps

Posted by Elizabeth Kaiser on Wed, Aug 24, 2011 @ 09:08 AM

Submitted By Dave Stoltenberg, Dredge Rental Specialist with SRS Crisafulli

An in-depth article in the July 2011 issue of WaterWorld describes the wide variety of mechanical seals used for water and wastewater pumps. 

Waterworld
The article "Back to Basics:  Mechanical Seals for Water and Wastewater Pumps", by Allan R. Budris, notes that mechanical seals are the number one cause of pump failures; it discusses the major types of mechanical seals used for water and wastewater pumps and each style's advantages and disadvantages.  Mechanical seal types presented include:  

  • Conventional
  • Pusher
  • Non-Pusher
  • Unbalanced
  • Balanced
  • Cartridge

SRS Crisafulli specializes in pumping slurries, sediments, and sludges - all so-called dirty water.  We continuously strive to ensure our pumps and dredges are equipped with the best and most long-lasting seals available. 

 

Read the full WaterWorld article

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Rancher Darwin Pfaffinger, Smith-Pfaffinger Ranch says ..."Our Crisafulli Pump is probably the most effective and trouble-free piece of equipment we own."

Read SRS Crisafulli pumps and power units case histories and testimonials.

Read SRS Crisafulli vertical pump case histories and testimonials.

Topics: srs crisafulli, pumps and power units, vertical pump