New Kids on the Block

TIPS FROM THE SERVICE BENCH

Phillips and Allen have dominated machine, sheet metal and cap screws for a long time. They are popular, easy to use and easily recognizable. But Phillips and Allen are looking over their shoulders! There are a couple of New Kids on the Block!

The new kids’ names are Torx and Pozidriv. The names may sound foreign but they fit right in the machine screw neighborhood. More surface area and better geometry make these screws more resistant to cam-out — or stripping — as it is more widely known. KNF is still utilizing Phillips and Allen head screws but Torx and Pozidriv are definitely making their presence felt.

TORX

Figure #1 (click to enlarge)

Torx are called “star drive” by some, as the recess resembles a 6 pointed star. The six points of contact engagement allows for higher torque being applied than a conventional Allen hex drive of the same size. Torx sizes are denoted by a T, followed by a number from 1 to 100. Common sizes used for KNF products include T6, T10, T15, and T25.

Various Torx screws and drivers are depicted in Figure #1 (left); shown clockwise (from top-left): various Torx screw heads, Torx handles, Torx driver, Torx black & white image.

POZIDRIV

Figure #2 (click to enlarge)

Pozidriv screws are almost a cousin to Phillips. The Pozidriv (sometimes spelled incorrectly as “Pozidrive”) is actually an improved version of the Phillips screw drive. The name is short for Positive Drive. This screw recess is very easy confused with Phillips if not noticed. Using a Phillips driver for Pozidriv screw recesses can easily result is a stripped head due to the different geometry of the driver itself. The Pozidriv has additional ribs in the driver tip which are received by the secondary web of the Pozidriv screw itself. This extra feature provides more turning strength due to the higher tool engagement. Figure #2 show various Pozidriv screws and drivers; shown clockwise (from top-left): Pozidriv screw heads, Pozidriv handles, Pozidriv driver, black & white image of Pozidriv.

Pozidriv drive bits are designated by the letters “PZ” plus a size code of 0, 1, 2, 3, 4 or 5. Common at KNF are the 0, 1, and 2 sizes. The drivers themselves will have a PZ marking and size code, and possibly the Pozidriv image on the handle butt.

The Pozidriv screws are visually distinguishable from Phillips by a set of radial indents set at 45° from the main cross recess on the head of the screw. These markings are sometime hard to see on plated or treated screws as the treatment may fill in the slighter 45 degree markings.

Please take care to look at these screws carefully before removing for service. Using the right driver will make your servicing quick and efficient. If you are in doubt of which screw is used on your KNF pump, please contact us. We are here for you.

WELCOME TO THE NEIGHBORHOOD

They don’t make things the way the used to, and this can be a good thing, since the latest tools usually incorporate technological advances that improve performance. Please give the “New Kids on the Block” a chance, they are proving to be hard workers!

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100,000 Hours and Counting!

On February 4, 2005, KNF USA engineers entered the temperature-controlled space of the “Life Test Room” in Trenton, NJ to initiate prototype testing for a specially-modified version of the KNF N 838 series diaphragm pump. At the time, the custom-designed OEM vacuum pump was being developed for a Fortune 100 medical device manufacturer, as an integral component of their immunoassay and clinical chemistry analyzer. The KNF pump would need to perform its duty – vacuum aspiration of biological samples – quickly and quietly, while ensuring precision and durability over the life of the pump. Like all spec-driven KNF project pumps, the custom-engineered N 838 vacuum pump was to undergo substantial testing to ensure accuracy, reliability, and overall quality.

KNF Life Test Room

A peek inside the carefully controlled conditions of KNF’s Life Test Room

Among all tests performed by the KNF R&D team, the Life Test may be the most valuable as it simulates the rigorous operating conditions often found in real-world environments – providing valuable data which is used to further improve pump performance. KNF pumps that undergo this particular test are operated under a continuous duty cycle, at high load, in unfavorable temperatures. Collectively, these test settings amount to what KNF Engineers use to determine a “worst case scenario”. In short, the Life Test is employed as a means to identify specific opportunities for improvement, while simultaneously gauging the life span of the pump in its current configuration.

The specially-modified version of KNF’s N 838 diaphragm vacuum pump has been running in a controlled test environment since Feb. 4, 2005.

Remarkably, from the date this post is written, over 12 years (105,189 hours) have passed since Life Testing began for this special N 838 project pump. You read that correctly; the incredibly durable N 838 pump is still running strong after more than a decade! This impressive test run time represents the longest continuous duty timeframe ever recorded at KNF Neuberger. It should also be noted that this record-setting operating life was achieved with only a few minor updates including diaphragm replacements at 30K and 60K hours. Despite advancements in both pump technology and testing procedures, engineers at KNF will continue to operate this extraordinarily resilient pump, in the Life Test Room, until it has completed a full lifetime…whenever that may be.

To put this unbelievable achievement into perspective, we have compiled a list of historical events* that have occurred since the start of the N 838 project pump Life Test:

  • 2005 (Aug) – Hurricane Katrina makes landfall, devastating the US Gulf Coast
  • 2006 (Jul) – Twitter is launched
  • 2007 (Jun) – Apple releases the iPhone
  • 2008 (Nov) – The United States elects Barack Obama president
  • 2009 (Jul) – Roger Federer wins record 15th grand slam at Wimbledon
  • 2010 (Oct) – All 33 Chilean miners are rescued after being trapped for a record 69 days underground
  • 2011 (Apr) – Fidel Castro resigns from the Communist Party of Cuba’s central committee
  • 2012 (Nov) – Scientists detect evidence of light from the universe’s first stars
  • 2013 (Jul) – Detroit, Michigan becomes the largest U.S. municipality to file for bankruptcy
  • 2014 (Mar) – Malaysia Airlines flight 370 disappears kicking off the most expensive search effort ever
  • 2015 (Oct) – China announces the end to their one-child policy after 35 years
  • 2016 (Nov) – Donald Trump is elected President of the United States
  • 2017 (Jan) – World’s largest dinosaur footprint (1.7 meters) found in Western Australia

* events chosen, at random, from www.onthisday.com

Like Oil and Water, and Ethylbenzene?

Chemical Resistance Compatibility

Tips From the Service Bench

Technology TIP

When pumping liquids, you must be sure flow path wetted materials are compatible with intended media. If not researched and tested, issues may arise in the field that may impact product life and maintenance schedules.

While Chemical Compatibility Charts are a good place to start your research, there is typically a standard disclaimer at the bottom that limits their application and places the responsibility on you the buyer, such as:

Warning: The information in this chart is to be used as a guide, ONLY. Although believed to be accurate, actual decisions on material selection need to be thoroughly tested and evaluated by the customer for each specific application. It is the full responsibility of the customer to perform and evaluate the compatibility of materials for their specific requirements. The manufacturer takes no responsibility, etc., etc…


ARE WE COMPATIBLE?

Polymer components exposed to incompatible media can experience swelling or loss of physical properties. When severe, these effects can lead to degradation of pump performance, reduced pump life, leakage, and even pump failure. These issues are avoided with proper material selection. Many pump manufacturers provide a selection of flow path materials to meet most needs, and some provide additional material options for exceptional cases.

TESTING OUR RELATIONSHIP

So, how do you go about testing chemical compatibility? You can get test swatches of possible polymer materials. But, results using test swatches can be less than applicable since they may be much thinner or thicker than the actual parts used in pumps. KNF offers a better way to assist your compatibility decisions, with our Chemical Resistance Test Kit (p/n 173610). This kit contains our most popular head plates and elastomer valves materials. These are actual production parts in current use, so they offer the best test subjects possible. For each material, two parts are supplied – one for resistance testing, the other as a comparison reference. Simple instructions will guide you through the static soak test process.

Chemical Resistance Kit Materials

Kit materials: (1) PEEK (2) PPS (3) PVDF (4) PP (5) FFKM-A (6) FKM (7) EPDM (8) FFKM-B (9) FFKM-C

SUMMARY

In a typical fluidic system, component lifetime will be influenced by several variables beyond simple compatibility of the liquid media, including chemical concentration, liquid temperature, operating pressure, flow rate, and exposure to abrasive materials. A static soak test cannot, therefore, replace a long-term validation test with a pump running in a real system under system parameters. But, a static soak test is well suited as part of an initial screening to identify and eliminate materials which are clearly incompatible with expected liquids.

Contact KNF today for a Chemical Resistant Test Kit and get pumping with confidence!

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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.

New KNF Laboratory Products Catalog Available

KNF Neuberger Inc. has recently published an updated Laboratory Products Catalog. The 33-page catalog reflects the newly expanded range of laboratory products offered by KNF Neuberger, Inc. which includes: a complete line of vacuum pumps and accessories, liquid transfer pumps, dosing/metering pumps, rotary evaporators, and vacuum systems.

Organized by application, this comprehensive guide presents the best product selections for rotary evaporation/distillation, degassing, filtration/SPE, fluid aspiration, gel drying, centrifugal concentration, vacuum ovens, multi-user vacuum systems, and metering and transferring liquid. In addition, this piece includes handy product charts for easy comparison.

View the new Laboratory Products Catalog here. Or, request a high-resolution printed version via postal mail by completing the form below.

KNF Associates Discuss MedTech Pump Design Trends with MDDI

Pumps for Medical TechnologyThe following excerpt is from the MDDI article, “Pump Designs Flow Toward Smaller Sizes“.


As medical devices require smaller pumps that fulfill rigorous design requirements, the relationship between OEMs and suppliers is shifting.

A medical device that manages the movement of a gas or a fluid relies on a pump to carry out the application. Advances in technology enable pump suppliers to provide pumps capable of addressing increasingly complex medical device requirements. But industry pressures are also changing the nature of the relationship between OEMs and their suppliers.

At one time, medical device companies looked at suppliers simply as a way to outsource work and reduce costs, said Dave Vanderbeck, business development manager for Trenton, NJ-based KNF Neuberger. While suppliers can help OEMs reduce their costs, Vanderbeck increasingly now sees OEMs turning to their pump suppliers for design expertise.

Read the full article at MDDIonline.com >>

Technology TIP: Measurement of Pulsating Flow

INTRODUCTION

TechTIP

Like most companies producing gas pumps, KNF uses glass tube and float type flowmeters to measure flow during pump production testing. This type of flowmeter has been used for several decades as they are fast-acting, reliable, and accurate. The normal industry practice is to calibrate this class of instrument using laminar flow. Unfortunately, the pulsating flow from reciprocating pumps produces an artificially high flowrate reading compared to the laminar flow calibration. As a result, all diaphragm and piston pump manufacturers using traditional flowmeters will end up promoting higher flow rate values than what the pumps actually provide.

OUR GOAL

measurement-flow-blogAt KNF, we are passionate about meeting the engineering design challenges of our customers. Our goal is to provide our customers with pumps that meet the actual needs of the system in which they are installed. Along with this goal comes the responsibility to provide data that best represents the performance capabilities for each pump produced at KNF. Simply stated, we want our customers to know the flow rate values we provide will accurately correspond to the actual flow produced by the pump — the true amount of gas delivered; not just an artificially inflated reading.

The flow measurement discrepancy manifests during system-level performance comparisons between continuous flow (non-pulsating) and pulsating pump types, reported to provide the same flow rates. The non-pulsating pump winds up delivering greater flow performance than the pulsating pump that was erroneously thought to be equivalent, skewing results in favor of the non-pulsating pump type.

TechTIP_MoPF_fig1

Figure 1: KNF pulsation-compensated flowmeter

THE SOLUTION

To address this situation, several years of research and development by our flow experts at the KNF Gas Pump Design Center in Freiburg, Germany has culminated in an advanced system for the measurement of pulsating flow. KNF has made an investment to implement this new technology. The resulting pulsation-compensated flowmeters (see Figure 1) are tuned and calibrated to measure pulsating flow more precisely than the traditional glass tube and float type flowmeters.

 

The more accurate flow readings from our pulsation-compensated measurement standard show lower values for flow than the laminar flow based systems used in the past. This document describes why your pump is still providing the same flow performance even though the measured and recorded flow value is lower. Glass tube and float type flowmeters are also called variable area flowmeters as the cross sectional area of the tube varies from smaller at the bottom to larger at the top (see Figure 2 below).

Figure 2

Figure 2: Cross-section illustration of a float type flowmeter

Pulsating flow always creates a higher reading in a float type flowmeter. The reason is that the float cannot move downward quickly enough between pulses. The float will remain on the top of the flow wave (see Figure 3 below). KNF has been aware of this phenomenon for quite some time and has been continually investigating better ways to attenuate the effect of the pulsation. The pulsation-compensated KNF flowmeter assemblies include physical components to minimize the effect of the pulsations.

Figure 3

Figure 3: Impact of pulsation on flowmeter readings

Simply put, our pulsation-compensated flowmeters are dampened to reduce the effect of the pulsations — these values are represented by the green line in the figure below. A dampened flowmeter may read pulsating flow too high if it was calibrated using laminar flow — that is why we use pulsating flow to calibrate our pumps at KNF. Flowmeters with little or no dampening will read artificially high as shown by the red lines.

SUMMARY

This advanced flow measurement system combines variable area flowmeters with a mass-flow calibration system. Optimized for pulsating flow, the system provides the most accurate measurement of flow available today. The improved accuracy is shown in Figure 4 (below).

Figure 4

Figure 4: KNF flowmeter reading (optimized for pulsating flow).

The chart shows flowmeters with a range of 2 – 10 liters per minute calibrated using pulsating and laminar flow compared to a target flow established by a mass flow meter. While this improvement is typical, actual results may vary across the flowmeter size ranges.

To learn more about KNF’s advanced flow measurement system please contact a KNF applications engineer.