This article will define a business case for achieving significant rotating equipment maintenance and energy cost reduction at industrial and municipal facilities.
Topic Sponsor
Top Instrumentation Articles
Pulsation and water hammer can be limited with proper forethought and equipment.
Lubricated machines require clean, dry oil to work properly. Recent studies have determined that as much as 80 percent of all failures and wear problems that hydraulic and lubricated equipment experience are due to oil contamination. The most damaging forms of contamination are particulates and moisture.
When it comes to pressure and flow, variable speed pumping applications can be divided into three basic categories. Constant pressure-variable flow (Cp-Vf) attempts to keep pressure relatively constant over a range of flows. Constant flow-variable pressure (Cf-Vp) tries to achieve the opposite by using varying pressure to keep flow constant. Variable pressure-variable flow (Vp-Vf) applications can accommodate a change in both.
Of the technologies available for condition monitoring of rotating equipment, the quickest return on investment is from vibration analysis. For the novice, vibration data seems complex and is generally difficult to assess compared to other techniques. Once trained, however, the novice can recognize the patterns and diagnose a machine problem.
Traditional control techniques examine the "running" status and the "not ready" status of the control circuit. While this method has served well for decades, it does have limitations. First, monitoring the contact of a starter does not detect if the wires have become disconnected, or if the linkage between the pump and motor is intact. Likewise, the "not ready" status will indicate an electrical problem is present, but it will not identify the problem, or how it occurred.
One electrical equipment specialist is relying on a cleaning system to ensure that a variety of stamped and turned parts are thoroughly degreased at their production facility.
Although the use of transmitters in pressure measurement is growing, mechanical pressure gauges are still used on most systems as local pressure display to back up electrical readings. The selection and installation of these gauges can be difficult in certain locations. Harsh conditions that can require special consideration include vibration, pressure pulsation, overpressure, corrosive media and extreme process and ambient temperatures. This article is designed to address harsh conditions with best practice recommendations to extend gauge life and provide for the safest installation possible.
While it is valid to state that energy efficiency is defined as the same level of production achieved at an overall lower energy cost, it is equally important for today's machine builders and automation engineers to remember an energy efficient system can actually translate into higher productivity. This is achievable through a comprehensive approach to energy management.
Latest Instrumentation Articles
This article will define a business case for achieving significant rotating equipment maintenance and energy cost reduction at industrial and municipal facilities.
The town of Walden rests on a high glacial plain in Colorado, just 20 miles from the Wyoming border in Jackson County. Situated in the center of a large open valley called North Park, the 734 residents (based on the 2000 census) of the town and the surrounding area refer to themselves as "North Parkers."
Electric drives are used in various applications in the oil and gas industry for varying motor speeds driving critical components, including pumps, fans and compressors. Both AC and DC drives are used, but AC units dominate most applications. This article explores some of the recent trends and issues in the European electric drives market.
Even when a redundant pumping system is in place, it can be advisable to monitor the condition of the operating units in critical applications where maintaining production depends on motor-pump reliability.
Comparing the vibration performance of identical or like machines can be used to detect defects and judge their severity.
Beating occurs when two dynamic excitation sources (forces) are close together in frequency, and a pathway allows the two excitation forces to transfer to each other. The beating effect results because the frequencies are so close to each other that the waveforms alternately reinforce each other at some times and cancel each other at other times. When the vibration from each source adds constructively, the vibration increases. When the vibration adds destructively, the vibration decreases.
Monitoring vibration—a valuable tool in predictive/preventive maintenance programs
Frequency analysis is an important method of vibration analysis. It provides information on vibration sources and helps identify those components in the vibration signal that are often small, but nevertheless important, for diagnosis. Each vibration can be attributed to a particular excitation source or machine part.
If pump cavitation is not detected and quickly eliminated, significant damage can occur to the impeller and other internal components. Since cavitation (the formation and collapse of vapor bubbles in the pumped fluid as it passes through the pump impeller) is often temporary or even induced by the process, timely knowledge of the condition is extremely important so operators can act to alleviate the problem and prevent damage.
Explore hermetically sealed gauging probes for hostile environments like saw mills and wood processing plants.
Columns and Blogs
In this multi-part series, we will investigate several aspects of centrifugal pump efficiency.
First of Five Parts
Since the original publication of this draft standard in the January 2008 issue of Pumps & Systems, I have received feedback, encouragement, numerous questions and criticism. The draft listed three basic levels of repair.
The McGraw-Hill scientific dictionary [5] states that a volute is "a spiral casing for a centrifugal pump... designed so that speed will be converted to pressure."
