Thread Seal Tape, a Fitting Friend

Tips From the Service Bench

By design, vacuum pumps pull gas or liquid in on the inlet side and expel media on the exhaust side. One prevalent issue to avoid, in order to ensure that the pump keeps operating to full potential, is keeping unwanted material out of the pump head and valves.

Many vacuum pump plumbing connections are made with hose connectors and fittings. One standard fitting thread is the National Pipe Thread (NPT). The threads on an NPT fitting are tapered for sealing, and are often used with a thread sealant, such as Thread Seal tape.

A recurring issue seen by our Service Department is loose Thread Seal tape unintentionally ingested into a pump (see photos below). The loose tape gets pulled in by the vacuum and lodges between the valve and valve seat. This can result in a loss of performance in the system and headaches for the pump user. The cause of this reduced performance is often not readily apparent, either.

Figure 1: Actual photos of ingested Thread Seal tape found within pump heads.

Once ingested, tape will not be expelled on its own as the path through the pump head is not designed to allow long/stringy solids to move through it. The removal of the tape debris involves disassembly of the pump head assembly, removal of the tape and re-assembly after inspection of all the components. This is time consuming and can be avoided.

One way to avoid ingested Thread Seal tape is to understand how the tape works in conjunction with the fitting and threaded port hole. The taper on NPT threads allows them to form a seal when torqued, as the flanks of the threads compress against each other. The fittings seal on the actual thread of the fitting and the hole. The fitting does not necessarily have to be installed to full thread depth as it is sealing on the thread itself.

DO’S

Figure 2: Apply Thread Seal tape

• Wrap the tape clockwise (facing the threaded portion) so that it follows the direction that the fitting will be threaded into the port (see Figure 2). Winding the tape in this direction will prevent the tape from unwinding during the tightening process.

• Use a Thread Seal tape that is narrow enough so it does not cover the first two threads of the fitting (see Figure 3). The first of the male fitting threads are the smallest in diameter and any tape wound onto these threads may actually be cut off as the fitting engages. The cut off tape may then be pulled into the pump head by the gas or liquid flow.

Figure 3: Correct application of Thread Seal tape

• Use 2-4 wraps of Thread Seal tape. You may need to adjust the number of wraps due to specific tolerances.

• Start the fitting by hand to ensure no cross threading occurs.

• Tighten according to fitting manufacturer specifications.

DONT’S

Figure 4: Incorrect application of Thread Seal tape

• Don’t wrap the tape covering the bottom of the fitting. Leave two threads free of tape (see Figure 4).

• Don’t feel the need to tighten fitting until the hex is flush. The sealing occurs on the tapered thread. It is OK if a few threads are left visible as long as the fitting is tightened to the manufacturers specified torque.

WRAP UP

Learning to apply Thread Seal tape properly will serve you well. When used properly, Thread Seal tape is a wonderful sealant. It is inexpensive and works in many different applications. It is easy to apply and lubricates the fitting and threaded hole assembly process. It also prevents possible corrosion at this interface and aids fitting removal.

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The Bear, The Pump, and Three Forks: A Tale of Sabotage Near Godfather Lake

From the time KNF was founded, “durability” has been one of the most distinguishing traits of our pumps. We feel a strong sense of pride whenever our customers use adjectives such as: “strong”, “enduring”, and “tough” when describing our products. That said, there are rare occurrences when a KNF pump succumbs to unusually extreme punishment. Not too long ago, a KNF customer, Brian Jarrell, informed us of one such example.

Brian is the Recreation Director at The Lodge and Spa at Three Forks Ranch, a luxury Resort and Spa approximately 40 miles north of Steamboat Springs, Colorado. The sprawling, 50,000-acre resort offers beautiful landscapes, scenic mountain vistas, various year-round activities, and upscale amenities. As part of his duties, Brian is responsible for maintaining ponds and other natural features across the huge property. To that end, many bodies of water around The Lodge, including nearby Godfather Lake, are equipped with solar-powered aeration systems. These aeration systems employ KNF N 828 gas pumps to inject air into the water for improved clarity and quality. When Brian needed help with his system’s pump, he called KNF and told us his wild story of a shaggy saboteur.

A visitor admires the wildlife & natural beauty of Three Forks Ranch (photo via threeforksranch.com)

One day, while making his usual checks around the property, Brian approached a pond to find that the nearby aeration system was completely silent. As he examined the control box, it became evident that the protective cover had been completely ripped off. According to Brian, a large black bear – 7 feet tall and 450 pounds – had destroyed the cover protecting the aeration system’s electronic components. As bad luck would have it, heavy snow soon fell over the exposed electrical components of the system, short-circuiting one of the two KNF pumps inside.

These circumstances are certainly extraordinary, and even frightening considering that a huge bear was probably lurking nearby while Brian was examining the damage from only a few hours earlier. However, according to Brian, scenarios involving wild animals are nothing unusual in his line of work. “We have had animals destroy our property in the past – problems with elk and bear chewing wires.” Brian calmly elaborated, “They are typically searching for food when they stumble onto a piece of equipment and become very curious. This bear may have been bored and was likely looking for something to do.” Well it certainly appears that this bear found something to do! On the bright side, this was the very first incident involving aeration systems on the property. Prior to the curious and destructive bear, both system and pump were “running just as strong as when they were originally installed” in 2004.

The suspect: Ursus americanus aka American Black Bear

The suspected saboteur: Ursus americanus (aka American Black Bear)

After finding the mauled machine, Brian soon contacted a KNF Technical Sales representative and, after a “painless and easy” conversation, he was on his way to receiving a replacement pump. When asked about the required repairs, Brian seemed almost relieved, “The whole thing was taken care of within a matter of hours. I am very appreciative of KNF”. In fact, he rates his experience with KNF a 10 out of 10. We’re glad to know that Brian’s experience was  positive, and we hope that the local black bear population seeks entertainment elsewhere in the wilds of Colorado.

Safe, Gas-tight Transfer of Dangerous and/or Expensive Media

The following is a case study presenting the issues encountered and overcome when problem-solving a pyrophoric gas transfer application with KNF customer, Air Products and Chemicals.

INTRODUCTION

Spontaneously-Combustible-SignAir Products is a leading international manufacturer of industrial gases and chemicals. With a staff of over 21,000, the company, based in Pennsylvania, operates in 50 countries across the globe and supplies a wide variety of processing media for myriad applications and industries.

Among goods produced specifically for the semiconductor and solar industry, Air Products manufactures a special gas mixture employed in etching and gas deposition processes to coat silicon wafers and glass substrates; these methods help, for example, to create the active films in flat panel displays and solar cells.

Owing to their pyrophoric properties, the utmost care is required both when manufacturing and using these gases. All system components that store or transfer the gases must therefore prevent air contamination. Should such gases come into contact with air, an exothermic reaction takes place in which a telltale oxidation product is created and deposited in the form of a white coating.

>> Read the Complete Case Study

KNF Exhibiting at the World’s Largest Printing Equipment Show

reprographic printingAs a trusted partner to many of the world’s leading industrial reprographic printer manufacturers, KNF is preparing to showcase its latest product developments at Drupa 2016. Considered the world’s largest printing equipment exhibition, Drupa is open every three years in Dusseldorf, Germany. This year, the show runs from May 31st through June 10th, and KNF is excited to be a part of it.

At the show, KNF will be exhibiting its latest product developments including liquid pumps with flow rates from microLiters/min to 12 L/min+ and gas pumps with flow rates from microLiters to 300 L/min. Additionally, KNF offers a wide selection of pumps that can be optimized for specific needs through engineer-to-engineer collaboration. Optional materials, motor types, fluid connections and other modifications are available to optimize performance, life, and cost at any quantity.

KNF liquid and gas pumps perform important ink handling tasks, including the ink transfer to print heads, ink degassing, print head cleaning, vacuum generation for print head meniscus control, and ink circulation. From continuous inkjet to drop-on-demand, from large format printing to product barcoding, KNF has the pumps needed for high-quality, consistent printing.

Please plan to stop by our booth in Hall 4, booth B01 if you will be attending Drupa 2016. To learn more about KNF pumps for reprographic printing visit www.knfusa.com/reprographics or read our related Application Notes:

KNF OEM Diaphragm Pumps Used in Multiple Environmental Studies

A customer recently brought five environmental studies, ranging from 2013 to 1996, to our attention. Each of the studies details research conducted with one common component: a KNF OEM pump, which proved integral for sample collection or transfer during the analyses. Of the five studies, we cherry-picked two air-toxics studies for your further reading. However, here’s the listing of all five:

  1. Walter 2013 High Res Measurements Atmospheric Hydrogen West African Coast Mauritania
  2. Querino 2011 Methane Flux Vertical Gradient Mixing Ratio Measurements in a Tropical Forest
  3. Bailey 2010 Southwest Indianapolis Air Toxics Study
  4. Romashkin 2001 In Situ Measurements Long Lived Trace Gases Lower Stratosphere Gas Chromatography
  5. Elkins 1996 Airborne Gas Chromatography In Situ Measurements Long Lived Species Upper Troposphere Lower Stratosphere

KNF Environmental Pumps for Gas Sampling and AnalysisWe’re very proud KNF pumps are relied upon within ambient, source and portable devices for environmental sample collection and analysis. For example, the 2010 study listed above details a project in which the Indiana Department of Environmental Management (IDEM), the U.S. EPA, the City of Indianapolis, and a diverse group of stakeholders teamed up to conduct an air toxics study in southwestern Indianapolis, Indiana (this region was identified by the U.S. EPA National Air Toxics Assessment [NATA] in 1996 and 1999 to be an area of potential concern for cancer risk from air toxics).

A KNF pump was used to enable the analysis of the total non-methane organic carbon (TNMOC) concentration of ambient air. For a history lesson, the Clean Air Act Amendments of 1990 required the EPA’s Office of Air Quality Planning and Standards to set National Ambient Air Quality Standard for the “criteria” pollutant, ozone. In areas of the country where the NAAQS for ozone is being exceeded, additional measurements of the ambient nonmethane organic compound (NMOC) concentration are needed to assist the affected States in developing revised ozone control strategies. Measurements of ambient NMOC are important to the control of volatile organic compounds (VOCs) that are precursors to atmospheric ozone.

Therefore, a reliable pump was essential for the collection of air samples with potentially harmful toxics. Simultaneously, it was critical for the pump to collect samples in a manner that didn’t change or contaminate the samples. KNF pumps, known for their reliability and chemical inertness, are ideally situated for this type of application. Additionally, their extremely high gas tightness allows for the accurate and complete collection of media, without the risk of sample loss, dilution, or contamination.

Also, in 2001, a study, titled In Situ Measurements of Long-Lived Trace Gases in the Lower Stratosphere by Gas Chromatography, utilized the KNF NMP 830 pump (referenced as UNMP 830 pump in article) . For this study, a four-channel gas chromatograph measured different air qualities in 70 and 140 second intervals. Air external to the aircraft was delivered to the instrument from an external, variable speed, two-stage, KNF diaphragm pump, driven by a brushless 24-V DC motor. The KNF pump was mounted on the aft wall, and was turned on by the ACATS-IV onboard computer when the ER-2 aircraft ascended through 87 kPa of atmospheric pressure.

Regarding this second study, there are a few points of interest we’d like our readers to note. First, the usage of the pump is a prime example of KNF application flexibility. The KNF NMP 830 micro pump is small; however, its footprint isn’t the only reason it was relied upon within this challenging design. For example, the pump in this application is pulling atmospheric samples at an extremely high altitude, measuring parts per billion (ppb) and parts per trillion (ppt). Expectedly, pump inertness is therefore paramount. Much like in the first study referenced above, environmental analysis customers have come to rely on KNF pump material options, including PTFE and stainless steel, and on the leak tightness of KNF pumps.

Additionally, the KNF pump used in this second study is driven by a brushless DC (BLDC) motor, which helps meet the small size mandate. BLDC allows flow rates to be adjusted as needed, helping to extend the lifecycle and reliability of a device. Motor adjustment is also particularly important for this application, because at high elevations, fewer air molecules are available to blow across the pump for cooling. Therefore, the pump faces the risk of overheating. However, the ability to adjust and operate the motor at a lower voltage and speed helps to mitigate this concern. The small and lightweight design of KNF micro gas pumps even allows for energy-efficient battery operation.

Also of note, there’s far less ambient pressure at the elevation at which the pump in this study is operating, resulting in less pressure on both the top and undersides of the diaphragm. This condition is certainly not ideal for pump operation, which further adds to the difficulty of this application. This, and the other challenges presented by high altitude operation and ppb/ppt detection require a specification-driven, individually-tailored pump. KNF excels in designing and configuring pumps to exacting requirements such as these. In fact, over 80 percent of KNF’s business involves custom-engineered pump solutions.

To round out this review, the first and second studies listed above used KNF pumps to flush sample flasks prior to sampling, and to collect and fill flasks, respectively. The last study used a KNF pump to collect samples in a high altitude study with a set-up similar to the Romashkin 2001 study, which was discussed above.

Summing up this entry to The Pump Post, each of the five studies offers a constant theme of KNF OEM pumps being well-suited for environmental sample collection and analysis applications. Please check back to learn more about KNF products in real-world applications!

Obtaining Optimal Process Pump Performance

KNF process pumps for hazardous media and environments

KNF N 860.3 FTI Ex – for pyrophoric gas application

In the latest edition of Processing magazine, KNF Process Pump Engineer, Rich Aerts highlights the importance of adapting a diaphragm pump to its operating conditions, media properties, and the needs of the process itself. The article includes a real-life example of pump materials being modified to achieve optimal performance, and illustrates the importance of gas-tightness in the manufacturing of pyrophoric processing gases.

Read article: “Transferring Pyrophoric Processing Media with Safety” (Processing, Sep. 2015) >>

The Right Pump to Meet Your Continuous Ink-jet Printing Requirements

Application Note: OEMAs the continuous ink-jet (CIJ) printing industry evolves, KNF remains a driving force behind the change from yesterday’s peristaltic and gear driven pumps, to today’s more efficient diaphragm pumps. In fact, KNF is well positioned to serve this industry, thanks to our CIJ applications knowledge and selection of readily-optimized liquid and gas handling diaphragm pumps.

Diaphragm pumps overcome common problems inherent with the use of peristaltic and gear pumps in CIJ applications. Peristaltic pumps have short tube life leading to maintenance issues or messy clean-up, while gear pumps have issues including performance decay, shed particles, high cost, and they cannot run dry. In contrast, our diaphragm pumps provide a greatly extended performance life, lower cost operation, leak-tightness, robust chemical resistance, the ability to handle challenging inks, and our liquid pumps are self-priming and can run wet or dry. In addition, KNF diaphragm pumps can include features such as logic-controlled brushless DC motors, special electrical connections and mounting plates, and dampeners for applications sensitive to pulsation.

Air, Gas & Liquid Diaphragm Pumps for Continuous Ink-jet Printers

KNF Neuberger, Inc. specializes in liquid transfer pumps for continuous ink-jet printing industry. Specific media applications include UV ink pumps, pumps for solvent-based inks, degassing pumps, and many more.

Typical functions that our pumps perform in drop-on-demand inkjet applications include:

  • Bulk ink supply/replenish
  • Ink degassing
  • System vacuum and pressure
  • Cleaning station
  • Anti-siphon at head
  • Gutter pump
  • Chemistry make up
  • Ink delivery
  • Debris cleaning
  • QC analysis

KNF is also proud to have contributed to the CIJ market’s successful evolution to now include industrial printers and decorators, mailing and labeling equipment, date/lot codes, bio-material dispensing, 3-D printers, printed electronics, and more.

View the complete Application Note for more information, including a list of KNF pumps for continuous ink-jet printing and a more complete list of KNF pump features and benefits for CIJ applications.