Tag Archives: tech tip

Tech Tip: Pump Cavitation

Posted by J.R. Banks  –  Processing & Flow Control
February 12, 2014

Centrifugal pump cavitation can be described as the formation and eventual collapse or implosion of vapor bubbles inside a pump.

A primary cause for cavitation is inadequate net positive suction head available (NPSHa). Poor NPSH leads to lower liquid pressure in the pump and if pressure in the eye of the impeller falls below the vapor pressure of the fluid, then cavitation can begin. When this takes place, the following can occur:

  • Pitting on impeller blades
  • Bearing failure
  • Mechanical seal failure
  • Shaft breakage
  • Poor efficiency

Preventing this type of pump cavitation may require several changes in system design or operations. Increasing pressure at the suction of the pump, decreasing the temperature of the liquid being pumped, and reducing head losses in the pump suction piping can increase the NPSH.

Implosion of vapor bubbles that form within the liquid inside a pump is what causes cavitation. Determining if this abnormal condition is taking place and how to correct will be vital to the longevity of your pump.

Sources: Engineers Edge, Enggcyclopedia

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Tech Tip: Hose Maintenance

Posted by Nelson-Jameson, Inc.  –  General, Processing & Flow Control
October 16, 2013

Prevent premature washdown hose wear and failure. Washdown hoses are often subjected to physical abuse while in service. Select a hose that meets or exceeds the application it is intended for. Consider temperature, pressure, and environmental concerns such as abrasion and chemical resistance. Every plant should have a maintenance/inspection plan in place to ensure the longest possible life of the hose.

Be sure to consider these steps in your plan:

  • Store hose properly when not in use.  Hose racks or reels are highly recommended to keep hoses off the floor and out of harms way. Pay attention to humidity, temperature, ozone and sunlight. Storing out of direct sunlight, in a room with moderate humidity and a temperature range of 50 to 75°F is recommended.
  • Always shut off the water supply to the hose when not in use and open the nozzle to relieve the pressure before storing.  Leaving water in the hose subjects it to constant pressure and will shorten the life of the hose.
  • Don’t pull the hose by the nozzle – this puts undo stress on the connection point.
  • Avoid exceeding the hose’s rated bend radius. Kinking of the hose can create weak spots in the hose wall. Consider using hoses with internal springs or kink guards to prevent kinking directly behind the coupler.
  • Never exceed the rated temperature and working pressure of a hose assembly.
  • Routinely inspect hose for wear and damage. Look for external damage – stiffness, discoloration, cuts, cracks, kinks, blisters, excessive abrasion and exposed or broken wires.
  • Regularly inspect fittings.  A hose should be removed from service if any fitting movement or damage is found that could prevent it from operating as intended.

Giving careful consideration to hose selection, care, maintenance and storage can provide optimum return on your investment. For more information contact our Process & Flow Control department at 800-826-8302.

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Tech Tip: Pump Maintenance

Posted by Nelson-Jameson, Inc.  –  Processing & Flow Control
August 21, 2013

Time is critical when equipment goes down. When a pump seal breaks, the pump is frequently opened on the floor and the parts are replaced. Although this practice can work when combined with thorough, regularly scheduled full maintenance programs, the workload can get so large that regular maintenance can slide. And then there are always fires to put out to add to the distractions.

When maintaining a pump, it is critical to remove it from the line and fully disassemble. Check parts for excessive wear and replace all of the parts in the kits. Not only on the wet end, but inspect the motor shaft and motor as well. If the bearings and shaft are not checked, the runout could be out of spec and the hundreds of dollars of new parts that are put in the wet end can be ruined within minutes – not to mention that those parts could end up in the product!

Also be sure to remove all rust from cast iron or carbon steel backplates and pump adapters. The rusting/oxidation process creates swelling that can impact the runout and create the same issues.

We recommend stainless steel pump adapters, as they are available for many pumps and motors, and will not rust.

Call our technical sales department for more information on pump maintenance at 800-826-8302.

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Tech Tip: Preventive Maintenance for Insect Electrocutors

Posted by Devon Vogel  –  Food Safety, General, Sanitation & Janitorial
May 29, 2013

FlySetting up a Preventive Maintenance Program for your insect electrocutors is the best way to ensure that your units are working to their full potential. Ideally, you would choose a month each year for your PM program to be done on the units. It is suggested that this is in the beginning of the year or Spring, with a new insect season.

The PM program should include checking the bulbs for their effectiveness, and making sure there are no other issues with the unit. Fluorescent bulbs that are used in insect electrocutors have an effective life span of 7000 hours or about 9 months. For your convenience, all of our Shat-R-Shield® or Insect-O-Cutor® bulbs come with year labels on them. This aids in your PM program as you are able to tell from a distance what year is labeled on the bulb, and whether it is time to be changed.

Even though a bulb may still be lit, does not mean it is attracting insects, so changing out yearly is recommended. For more information, visit our Learning Center.

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Tech Tip: Choosing the Proper Lubricant for Pumps & Valves

Posted by Nelson-Jameson, Inc.  –  Food Safety, General, Processing & Flow Control, Production & Material Handling, Sanitation & Janitorial
March 13, 2013

EPDM is the standard elastomer on many pumps and valves and is not compatible with petroleum-based products. Using lubricants such as the popular Petro-Gel in these applications is not a good choice as it will degrade your equipment elastomers and decrease the life of your parts.

Due to the high melting point, Petro-Gel and similar non-CIP lubricants have the potential to contaminate your product with bacteria such as Listeria. Petro-Gel has a melting point of 190°F, and typical CIP cycles are only 160-180°F, meaning the residue will not melt and clean away. If a spare part somehow came in contact with bacteria, the high melting point of these non-CIP lubricants would function to protect the bacteria during the CIP cycle and could contaminate your products!

To lubricate your EPDM pump and valve parts, use Haynes or McGlaughlin CIP films (312-2020 or 435-2005). With melting points of 120°F, they will wash away completely during your CIP cycle.

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