Keeping a clean and steady flow of air is extremely important in any enclosed environment, and particularly so in a lab environment where isolation and control of all elements and potential containments is so essential. That’s where the Air Flow Technology (AFT) engineering staff at Allentown Caging Equipment put their energy when designing their new generation of animal caging systems.

The driving force in terms of innovation and product development at Allentown Caging, the AFT department is responsible for designing and developing a range of airflow related products. For over 35 years, the company has been providing the biomedical research community with the most technologically advanced animal housing systems.

Recently, the AFT department designed two new products that offer improved ventilation of Allentown Caging’s P/NC Positive/Negative Control Systems.

The P/NC System is an individually ventilated caging system with 60 to 160 cages designed to hold up to 800 mice, rats, guinea pigs or other rodents. These safe and flexible environments are HEPA filtered, and can switch from positive to negative pressure at the “press of a button,” providing a safe environment for both the animals and laboratory personnel. These caging systems use microprocessor controlled supply and exhaust blowers to provide the required number of controlled air changes per hour. To help ensure that the systems maintain a stable air flow, and to measure air flow both into and out from the cages, Allentown Caging’s Air Flow Technology AFT team turned to Setra Systems of Boxborough, MA and that company’s differential pressure transducers.

Handling the pressure.
With more than 35 years experience in the design and manufacture of pressure measurement systems for HVAC control, Setra’s Model 265 differential pressure transducer was a perfect fit for the AFT team’s air flow monitoring and control needs. The team selected the Model 265, which is offered with ±0.25% accuracy (±0.4% optional and ±1% standard) in pressure ranges from ±0.1” W.C. up to 100” WC. The Model 265 provided the excellent stability and high level output that is required for high-efficiency, air control systems.

“We considered some less expensive options,” said a project engineer at Allentown Caging Equipment. “But we determined that Setra had the high level of quality and accuracy we were looking for – specifically accuracy in low range applications.” The Setra 265 is a key component in Allentown Caging’s SE6100 Smart Exhaust Pak, the unit that’s responsible for extracting air from the P/NC System’s animal cages. Custom-made for the P/NC System, the Smart Exhaust Pak features a microprocessor control board and “feed-back” control technology to automatically adjust the blower speed and maintain the desired 15-50 CFM airflow as the HEPA filters begins to load. The Setra 265 pressure transducer allows the SE6100 to constantly monitor the flow of evacuating air – air that’s replete with airborne particulates like dander, bedding and dust, as well as potential pathogens.

Allentown uses mass flow sensor technology with a hot tip anemometer on their supply blower to control the fan motor and adjust for HEPA filter loading. The problem with using this method for an exhaust system is that the delicate sensor would be exposed to airborne particles. This mass flow technology would require constant cleaning. These particles would block the hot tip and cause the unit to go out of calibration and greatly detract from accuracy. The Setra Model 265 allows Allentown to measure and monitor the pressure, permitting the Smart Exhaust Pak to precisely measure and control the P/NC System’s airflow accurately, and without the added costs of re-calibration and additional maintenance.

Detection made easy.
The Setra 265 is also central to Allentown Caging’s Range Finder Rack Flow and Cage Flow Detectors, which are also used with the P/NC cage rack. The Range Finder Rack Flow Detector provides supply or exhaust air confirmation for an entire ventilated rack, while the Cage Flow Detector provides cage-level airflow confirmation as low as 0.15 CFM, from cage to cage. The Range Finder products can be used while the ventilated rack is in service, and fully populated, with no disruption to its inhabitants. Both of these detectors utilize Setra’s transducer technology to provide simple, easy to read analog output, and accurate pressure measurement. The 265 transducers used in Range Finders measure low differential pressures from 0 to ±0.25” WC with a high level output accurate to +/- 0.4% of full scale.

“Our customers need to know how much fresh air their animals are getting in “real time,” said an engineer at Allentown Caging Equipment. “The Range Finder products with the Setra technology provide the simple and fast verification our customers are looking for – as easy as a green light for airflow that’s within the selected range, typically ±10%, and a red light signifying unacceptable airflow falling outside that range. Within seconds, the Range Finder solutions allow users to spot check every rack and every duct connection in the cage system.”

By taking advantage of the Setra 265’s precise pressure measurement and tight tolerances, Allentown Caging’s Air Flow Technology team was able to produce easy-to-operate air measurement and control solutions that don’t require an abundance of extra parts. Which means - with the P/NC Positive/Negative Control System serving as an environmentally sound cage system, the system’s residents aren’t the only ones who can breathe easier.

Whitney Systems of Chelmsford, MA builds a wide range of customized machinery designed to enhance productivity and product quality. The company designs and manufactures everything from machines for custom automation to O-ring insertion machines to test stands such as electrical testers, flow rate testers, endurance testers and leak testers. Unfortunately, after creating one such test stand, a ball valve leak tester for their customer, Metso Automation, Whitney learned that it was relying on a less than reliable test measurement device.

Whitney had built a machine that tested Metso's different ball valves for pressure decay. Metso makes cast iron, steel, stainless steel and brass ball valves that are used in a range of applications, including plumbing, air, water, gas, oil and other applications. Metso's metal and soft seated ball valves are a key element in the most demanding, high-cycling applications. They feature an innovative shaft/ball connection which works to assure tight shut-off, even with the lowest pressure differentials.

Whitney's ball valve leak tester is designed to provide comprehensive leak testing for many different series of Metso's Jamesbury brand ball valves. The machine is designed to test for pressure decay in four locations: at the stem of the ball valve handle, on either side of the ball, as well as through the ball itself. The operator puts the ball valve into a "nest" in the machine, and hits the start button, which initiates the formation of a pressure seal around the ball. A pneumatic actuator is used to open and close the ball valve. The ball valve being tested gets pressurized with 100 psi of air and a pressure transducer is used to pinpoint and measure pressure drops.

A pressure transducer fails the test. Unbeknownst to Whitney, when initially creating this ball valve leak tester for Metso, they had incorporated a faulty pressure transducer. The company that manufactured this transducer had changed its ratings, and did not notify Whitney of the change. So while the machine was testing for ball valve leaks, the transducer actually ruptured – it literally couldn't handle the line pressure, with the machine requiring testing at 100 psi. To make matters worse, Whitney sent the transducer back for repairs and, shortly after its return, the component ruptured again.

According to Whitney Systems, locating the exact cause of the problem wasn't as easy as it should have been. "When the old transducer broke, it took four to six weeks to figure out that our supplier had changed the rating on us."

Clearly Whitney needed to upgrade to a new transducer, but finding one that could meet the rigorous requirement of this ball valve tester wasn't easy. The transducer would have to be able to measure both very low pressure differential changes as well as withstand high line pressures.

Meeting the highest pressure demands. "We looked at a couple of transducers that could meet some of our needs, but they couldn't satisfy the 100 psi line pressure requirement," Whitney said. "When we spoke with Setra, we realized that they not only had a transducer that was rated to handle our high pressure needs, but they had it available, off the shelf, without requiring any customization. Within a very short number of days, we were back up and running with Setra's Model 235 pressure transducer in place."

Setra Systems Inc.'s Model 235 differential pressure transducer is actually designed for high line pressures up to 2500 psig. Used also in municipal gas distribution, oilfield gas recovery, coal mine ventilation and electricity generating plants, this versatile pressure transducer was exactly what Whitney needed.

According to Setra sales manager, Paul Richards, "The Model 235 is unique in its ability to handle high and low line pressure changes. The Model 235 virtually eliminates the need to balance the high and low pressure at installation to minimize line pressure error on a differential measurement. Users can expect a minimal low line pressure effect of <0.1% FS change per 100 psig line pressure change."

Said Whitney, "The Model 235's utmost accuracy allows us to ensure that the ball valves fall within Metso's acceptable leak rate of 0.45 cc per minute. Setra's patented technology was a great fit for both our application and our budget."

A unique inductive technological advance. The Model 235's excellent performance, typical to more expensive differential pressure transducers, is achieved through Setra's unique inductive sensing technology. Unlike competitive transducers, the Model 235 contains no liquid filled diaphragm and is not media-sensitive. This eliminates the possibility of batch contamination and thermal transient errors, as the only wetted parts exposed to media are stainless steel, alumina ceramic and glass.

The Model 235 is accurate to +/- 0.18% of full-scale output, with a total error band of +/- 0.5% full scale over the compensated temperature range of –20° to +160° F on 5 psig through 500 in. W.C. pressure ranges. There is virtually no shift in output at warm-up, and a typical update rate of 25ms makes this unit ideally suited for pressure applications that require a stable, fast response – applications like Whitney's ball valve leak tester.

"Since we started using the Setra 235, we haven't had any problems," Whitney concluded. "The transducers have proven both accurate and durable. In fact, we just recently bought our fourth transducer for the Metso test stands."

With high line pressure transducers in place, the people at Whitney Systems are actually feeling quite a bit of pressure relief. And their customers, like Metso can rest easier knowing that their ball valves are production-ready, having passed the most stringent of pressurized performance tests.

####

Whitney Systems of Chelmsford, MA builds a wide range of customized machinery designed to enhance productivity and product quality. The company designs and manufactures everything from machines for custom automation to O-ring insertion machines to test stands such as electrical testers, flow rate testers, endurance testers and leak testers. Unfortunately, after creating one such test stand, a ball valve leak tester for their customer, Metso Automation, Whitney learned that it was relying on a less than reliable test measurement device.

Whitney had built a machine that tested Metso’s different ball valves for pressure decay. Metso makes cast iron, steel, stainless steel and brass ball valves that are used in a range of applications, including plumbing, air, water, gas, oil and other applications. Metso’s metal and soft seated ball valves are a key element in the most demanding, high-cycling applications. They feature an innovative shaft/ball connection which works to assure tight shut-off, even with the lowest pressure differentials.

Whitney’s ball valve leak tester is designed to provide comprehensive leak testing for many different series of Metso’s Jamesbury brand ball valves. The machine is designed to test for pressure decay in four locations: at the stem of the ball valve handle, on either side of the ball, as well as through the ball itself. The operator puts the ball valve into a “nest” in the machine, and hits the start button, which initiates the formation of a pressure seal around the ball. A pneumatic actuator is used to open and close the ball valve. The ball valve being tested gets pressurized with 100 psi of air and a pressure transducer is used to pinpoint and measure pressure drops.

A pressure transducer fails the test.
Unbeknownst to Whitney, when initially creating this ball valve leak tester for Metso, they had incorporated a faulty pressure transducer. The company that manufactured this transducer had changed its ratings, and did not notify Whitney of the change. So while the machine was testing for ball valve leaks, the transducer actually ruptured – it literally couldn’t handle the line pressure, with the machine requiring testing at 100 psi. To make matters worse, Whitney sent the transducer back for repairs and, shortly after its return, the component ruptured again.

According to Whitney Systems, locating the exact cause of the problem wasn’t as easy as it should have been. “When the old transducer broke, it took four to six weeks to figure out that our supplier had changed the rating on us.”

Clearly Whitney needed to upgrade to a new transducer, but finding one that could meet the rigorous requirement of this ball valve tester wasn’t easy. The transducer would have to be able to measure both very low pressure differential changes as well as withstand high line pressures.

Meeting the highest pressure demands.
“We looked at a couple of transducers that could meet some of our needs, but they couldn’t satisfy the 100 psi line pressure requirement,” Whitney said. “When we spoke with Setra, we realized that they not only had a transducer that was rated to handle our high pressure needs, but they had it available, off the shelf, without requiring any customization. Within a very short number of days, we were back up and running with Setra’s Model 235 pressure transducer in place.”

Setra Systems Inc.’s Model 235 differential pressure transducer is actually designed for high line pressures up to 2500 psig. Used also in municipal gas distribution, oilfield gas recovery, coal mine ventilation and electricity generating plants, this versatile pressure transducer was exactly what Whitney needed.

According to Setra sales manager, Paul Richards, “The Model 235 is unique in its ability to handle high and low line pressure changes. The Model 235 virtually eliminates the need to balance the high and low pressure at installation to minimize line pressure error on a differential measurement. Users can expect a minimal low line pressure effect of <0.1% FS change per 100 psig line pressure change.”

Said Whitney, “The Model 235’s utmost accuracy allows us to ensure that the ball valves fall within Metso’s acceptable leak rate of 0.45 cc per minute. Setra’s patented technology was a great fit for both our application and our budget.”

A unique inductive technological advance.
The Model 235’s excellent performance, typical to more expensive differential pressure transducers, is achieved through Setra’s unique inductive sensing technology. Unlike competitive transducers, the Model 235 contains no liquid filled diaphragm and is not media-sensitive. This eliminates the possibility of batch contamination and thermal transient errors, as the only wetted parts exposed to media are stainless steel, alumina ceramic and glass.

The Model 235 is accurate to +/- 0.18% of full-scale output, with a total error band of +/- 0.5% full scale over the compensated temperature range of –20° to +160° F on 5 psig through 500 in. W.C. pressure ranges. There is virtually no shift in output at warm-up, and a typical update rate of 25ms makes this unit ideally suited for pressure applications that require a stable, fast response – applications like Whitney’s ball valve leak tester.

“Since we started using the Setra 235, we haven’t had any problems,” Whitney concluded. “The transducers have proven both accurate and durable. In fact, we just recently bought our fourth transducer for the Metso test stands.”

With high line pressure transducers in place, the people at Whitney Systems are actually feeling quite a bit of pressure relief. And their customers, like Metso can rest easier knowing that their ball valves are production-ready, having passed the most stringent of pressurized performance tests.

ControlAir Inc. announces the current-to-pressure (I/P) and voltage-to-pressure (E/P) Type 900X transducer, an innovative internal control and feedback system that provides accurate conversion of an electrical signal to a linearly proportional output pressure. Guaranteed accurate to +/- 0.10% of span, this series of transducers is loaded with features, plus, is rugged and versatile.

ControlAir's Type 900X series is tough. Housed in a NEMA 4X (IP65) enclosure that's ideal for remote locations and harsh environments, this transducer has a modular design that allows the user to wall, pipe, panel, DIN rail and manifold mount. The compact size provides for high-density mounting. Front and back porting provides piping flexibility. Electrical connections can be made with pigtail, DIN 43650 connector or terminal block. Calibration is simplified by the inclusion of a noninteractive zero and span.

Output pressures of up to 100 psig can be direct/reverse acting, full/split rangable. Maximum supply pressure of up to 100 psig does not need to be pre-regulated. Integral volume booster provides high airflow capacity of up to 12 scfm. The Type 900X series is available in port sizes of ¼ NPT (pneumatic) and ½ NPT (electric).

The 900X series can be calibrated, mounted, wired, and in operation quickly and easily for a variety of applications, including the outdoors or in washdown environments. Applications include valve actuation, pneumatic valve positioners, cylinders, clutches, brakes, dampers, louvers, pumps, web tensioning, flow and speed control.

For more information, ControlAir's website, offers full product specifications with pdf files, product CAD drawing files, and a company profile. ControlAir Inc. manufactures precision pneumatic and electropneumatic controls. ControlAir's markets include process control, semiconductor, printing and converting presses, diagnostic and surgical medical equipment, robotics, quality control, automotive, analyzers, compressors, pumps and paint equipment.

ControlAir Inc. announces the introduction of the Type- 590X I/P Transducer. This unique current-to-pressure transducer is small in size and light weight, yet is less sensitive to shock vibration and position change than most other I/P's. Conversion technology utilizing open loop control and a low mass magnet produces accurate pressure control at an economical cost. The Type-590X can mount in any position and is impervious to RFI/EMI interference.

The Type-590X I/P transducer converts a variable electrical signal to a linearly proportional pneumatic output. The small size allows for dense mounting in panels, can mount in any plane and is stable in high vibration environments. The Type-590X is approved by Factory Mutual (FM) and Canadian Standards Association (CSA) as intrinsically safe. It is also compliant with the ATEX directive 94/9/EC for equipment intended for use in potentially explosive atmospheres in Europe.

Type-590X is ideal for process control valve positioner applications used in HVAC, chemical, petrochemical, oil and gas, pharmaceutical and food processing markets. Other OEM applications include printing presses, textile machinery, tire machinery, paper machinery and paint spray systems.

Basic Specifications:

• Porting – 1/8" NPT
• Input signal – 4-20 mA
• Output ranges – 3-15, 3-27, 6-30 psig
• Maximum supply pressure – 22 psi (3-15 output), 42 psi (other outputs)
• Flow capacity – 2.4 SCFM
• Air consumption – 6 SCFH
• A manifold version is also available for electro-pneumatic valve positioner applications. Contact factory for details.

ControlAir Inc. manufactures precision pneumatic and electro-pneumatic controls. ControlAir's markets include oil and gas, process control, semiconductor, printing and converting presses, diagnostic and surgical medical equipment, robotics, quality control, automotive, analyzers, compressors, pumps and paint equipment. For more information, ControlAir's website, www.controlair.com, offers full product specifications with pdf files, 3D and 2D CAD models, and company profile.

Now there's a compact I/P transducer that delivers reliable high performance for the toughest applications in the most hazardous environments: the Type 950XP from ControlAir.The 950XP converts an electrical current signal to a stable, pneumatic output to actuate valves. Its NEMA 4X (IP65) housing is designed for both Intrinsically Safe* and Explosion-Proof* operation. Advanced circuitry includes electronic feedback control for superior vibration protection and highly accurate output.

With flow rates up to 12 SCFM(20m3/hr), the 950XP has the muscle to drive large valves and actuators. Yet because it typically consumes only .05 SCFM (0.11m3/hr), it not only costs less to buy, it costs less to operate as well. And because it takes impure air in stride, downtime is reduced, too.

The 950XP gives you big flexibility. Its small footprint can fit into tight spots. Its standard mounting bracket lets you mount it directly on a valve, wall, panel, or pipe. Optional, field-selectable process output ranges reduce downtime and inventory. And since the 950XP is position insensitive, it gives you even more freedom in mounting and connecting to valves and instruments.

As a result of this flexibility, installation goes faster. Easy access Zero and Span adjustments make bench or field calibration quick and easy. For operating versatility, you may choose direct, reverse, and split range modes .

Key Features:

· Compact Size

· Built-in Volume Booster – Up to 10 SCFM Flow Capacity

· Easy Wiring

· Multiple Inputs and Outputs

· RFI/EMI Protected

· Modular Control Pack

· Position-Insensitive – Can be mounted in any orientation

· Supply Pressure up to 100 PSIG

· Explosion-Proof, NEMA 4X (IP65) Housing

· Rugged; Highly Tolerant of Impure Air

· Optional Field-Selectable

· Non-Interactive Zero Span

· High Accuracy ± .1% of Span