Pumps & Systems, July 2007

The food processing industry is one of the largest manufacturing industries in the U.S., accounting for approximately 14 percent of the total U.S. manufacturing output. A typical food processing plant uses equipment of varying ages, constructed of a myriad of materials, including carbon steel, aluminum, stainless steel and plastics. Corrosion - an attack on a material due to a chemical or electrochemical reaction with a surrounding medium - can be an enemy of many of those materials.

Pumps & Systems, July 2007

Conclusion of our series covering applications in which they are used, why they are used, how they fail and things operators can check/do to maintain the performance of the seal flush plan.

Plan 52

Plan 52 uses an external reservoir to provide buffer fluid for the outer seal of an unpressurized dual seal arrangement. During normal operation, circulation is maintained by an internal pumping ring. The reservoir is usually continuously vented to a vapor recovery system and is maintained at a pressure that is usually at or near atmospheric pressure. The inner process seal of the dual unpressurized arrangement usually has its own flush plan.

Pumps & Systems, July 2007

Since the early 1970s, pressure sewer systems have been an effective method to move residential wastewater through small diameter pipes to collection facilities where other methods are less economical or less feasible.¹

The keys to understanding the differences between conventional gravity sewer systems and pressure sewer systems are the piping network and the reduction of solids size in the wastewater. Pressure sewer systems use grinder type pumps to reduce the solids present to particles, which can easily be moved through small diameter pipes.

Pumps & Systems, July 2007

When is a metering pump not just an ordinary metering pump? When it exceeds API 675 performance standards with "pulse-free" linear flow that is being accomplished through the latest technological improvements.

While many institutions and associations have developed performance criteria for metering pumps, the American Petroleum Institute (API) Standard 675 for controlled-volume, positive displacement pumps is perhaps the most widely cited. It specifies accuracy (performance at a set point) of ±1 percent, linearity (speed/flow rate relationship) of ±3 percent, and repeatability (return to set conditions) of ±3 percent.

Pumps & Systems, July 2007

Hose pumps have been around for many years, with some designs dating back more than 75 years. They are excellent devices for pumping slurries, due to their ability to handle very abrasive slurries. Hose pumps are also very good at dosing chemicals, since they are a positive placement device that can very accurately control the flow rate desired.

Pumps & Systems, July 2007

Intuition is wonderful, but sometimes deceiving. For example, I have always intuitively felt that "the better the alignment, the longer the pump life." But intuitively preaching about the horrors of bad alignment from an air-conditioned office is one thing; actually chasing a 0.001-in alignment issue under a 100-deg summer sun is something else entirely.

In other words, intuition does not address the real question: how much longer? So let's talk facts: what we know, not what we think we know.

Pumps & Systems, July 2007

When I first discovered the affinity laws, I was impressed by their simplicity, versatility, and power. For me, they held a certain allure. I believed I could use these three simple relationships to solve any pump problem:

Pumps & Systems, July 2007

Positive displacement pumps are known as the poor cousin in the global pumps market. With regard to the two broad product classifications, one being centrifugal and the other positive displacement (PD) pumps, the former dominates with nearly 70.0 percent of the 2006 market share revenues.

Pumps & Systems, July 2007

Q. What is a jet pump? I do not see any reference to it in your standards and would like to learn more about it.