Recently, we investigated numerous issues with mechanical seals failing in self-priming pumps on suction lift applications. In each instance the pump/system was not installed or operated properly. Root cause analysis suggested a misunderstanding of basic physics. We thought it would be beneficial to review a few fundamentals for pumps on suction lift installations. A suction lift simply
If time and money were no object, the pump OEM would be very happy to design a pump specifically for the customer’s unique operating point; it happens, but not very often. In essence, all single stage centrifugal pumps are designed for one operating point on the curve. This point is commonly referred to as the
Last month we reviewed basic vacuum principles. The reason was to better understand how to correctly measure the differential pressure across an operating pump. Understanding your suction pressure and knowing how to read a vacuum is critical in identifying performance issues. In the field, instruments measure in units of PSI …whether gauge, absolute or vacuum. When diagnosing issues,
The concept of vacuum mystifies some people when encountered on pump applications. Today, we hope to simplify the problem. Pressure vs. Vacuum Even in a vacuum there remains some pressure… it is simply a pressure at a magnitude below the surrounding atmospheric pressure. Vacuum does not necessarily mean the absence of all pressure; vacuum can be
We get calls from the field concerning issues with pumps that are experiencing performance issues. Typically we perform a triage scenario; we first figure out if the pump is on a suction lift arrangement and make sure the pump is notattempting to defy the laws of physics. Once that question is satisfied we then walk through the
MYTH: Factory Supplied Pumps are “Plug and Play”. Pumps shipped from the factory are NOT ready to be started when and as received in the field. As an annual ritual I am compelled to remind pump industry people that 99.35% (approx.) of industrial centrifugal pumps do not arrive ready to run and play – unfortunately this “Plug
Thanksgiving…At this time of year in America we purposefully pause and offer thanks for all we have. Suppose for a minute that in a fictional and make-believe universe you were a pump; what would you give thanks for? We share some ideas. This Pump is Grateful For… A balanced impeller, precise shaft alignment, robust foundation and solidly grouted
How fast was I going officer? Speed is a critical limit for any pump, but even more so for Positive Displacement (PD) pumps. The maximum allowable speed of a PD pump is determined by several factors including the viscosity and temperature of the pumpage. Other important factors are the level of abrasives in the product,
I recently received a phone call and subsequent email stating “my self-priming pump is not priming”. Both the phone call and the email were detailed with pictures and appropriate information to start the troubleshooting process. The pump was a model 2796 MTO 6 X 6 – 13 with a 10.625” diameter impeller turning at
Yes! Yes, we do. First, please pardon my paraphrasing of classic movie quotes. However, I think it is a great analogy when talking about gauges in pump systems. Depending on who you talk to … Some people think gauges are extremely important to the overall efficiency of the system, but others do not. As an
Today we will discuss ANSI pumps with a focus on Summit’s model 2196 product line. Pump Impeller Clearance When a pump leaves our OEM factory there are a minimum of five critical steps required (to be completed in the field) as part of commissioning and starting up the pump. One of these five key steps
Ever wonder why some impellers, fresh and new from the factory have holes in them? Or… why some impellers have those funny mini vanes on the back side? The short answer is to reduce the axial thrust in the pump and also to reduce the pressure in the stuffing box. Whenever you operate a
We have all heard the term “flush” used when discussing mechanical seals. The definition of a flush is “a stream brought in from an external source to the mechanical seal.” This plan (API Plan 32) is almost always used in conjunction with a close clearance throat bushing. The flush fluid must be brought into
Snoring pumps… ever heard of such a thing? I knew that pumps could run, burp, leak, stall and die (people “kill” them all the time), but I didn’t know that pumps could snore. Kidding aside, by definition a pump that is pumping a mixture of liquid and air is technically snoring. The term originates from the
This issue compliments an earlier issue (Volume 1 issue 12 from April 2018) on the same subject. I am frequently asked; should the discharge valve be open or closed when the pump is started? My answer is….it depends, but regardless the suction valve better be open. First Things First Let me state that as visitors to client facilities we
