Customer needs translate to improved products

Andy Mangell

A guest blog from Andy Mangell. Andy is the sales director at Premier Control Technologies, a UK based process control technologies and products distributor which represents Alicat products. Andy has over 30 years of experience with pressure and flow control instrumentation. He can be reached at andymangell@pctflow.com.

Alicat Scientific’s standard product line is fast, versatile and tough. Their instruments make our customers’ jobs easier and more accurate, while reducing the number of instruments required. People love how easy they are to use and the short lead time between ordering and receiving the instrument. For both OEM producers and small research operations, Alicat’s ability to refine and customize instruments for their specific process is key to getting the best instrument to the customer. Listening to what customers need and anticipating improvements is how Alicat has been able to innovate and be the fastest mass flow controller company.

Since its foundation some 27 years ago, the concept of constant innovation and product development has been pivotal to the company’s remarkable success. Specifically, areas such as bi-directional mass flow measurement, precision pressure control within dead-ended non-flowing applications, multi-parameter measurement and control, true multi-gas capability and high turn-down have all benefited from the dedication to innovation.

Bi-directional mass flow measurement

By the application of either a positive or negative set-point signal, Alicat has enabled the possibility to control flows into a process in one direction first and then to switch into the opposite direction. Alternatively, flows can be controlled into a closed process and then vented without the need for additional bleed valves. Due to the inherently bidirectional nature of the Alicat sensor, the flow is measured in both directions and a net total provided if required.

Dual-valve precision pressure control

Precise control of pressure reduction and pressure relief valves from a single setpoint signal ensures process pressure remains stable, independent of other variables. Such processes as head space pressure control, glass reactor protection and the elimination of costly out-gassing through continuous bleed valves all benefit from this innovation. Alicat electronic pressure controllers provide responsive, stable control of absolute, gauge or differential pressures in dead-ended processes.

Multi-parameter measurement and control

Measurement of multiple parameters on the one instrument (mass flow, volumetric flow, temperature and pressure) enables the user to eliminate additional components within a system and the pipework/fittings required to install them, in addition to cables and electronic signal conditioning. All parameters are displayed on a single screen for easy monitoring of process gases or liquids. Any of the measurement parameters can be enlarged in the centre position for reading at further distances from the instrument. All of the displayed parameters are measured in real time, which allows you to look at the device display and quickly get an idea of how your process is operating. When a process begins to falter, this information can significantly reduce the amount of time it takes to diagnose and repair the failure. All Alicat mass flow controllers can be changed to pressure controllers or volumetric controllers via digital interface or via the display. The user can monitor mass flow while controlling pressure or vice versa.

True multi-gas capability

COMPOSER ™ gas mix composition software, available with color display

COMPOSER ™ gas mix composition firmware, shown on a color display

Following continuous innovation and development over the years, Alicat instruments are now preloaded with up to 130 full gas calibrations, thereby eliminating the additional measurement uncertainty introduced by conversion factors. Complete NIST REFPROP gas properties data has been loaded for each of the gases, ensuring that both the standard accuracy and optional high accuracy statements remain valid, regardless of the gas. The benefits to the user are significant. Instruments are no longer limited to just one application; once a certain project has been fulfilled, the MFC can be used again for a different project with different gases. Similarly, even within a single project, fewer instruments are required to meet the needs of multiple gases or multiple flow rates.

Wide turn-down range

Turn-down ratio is a measure of the usable range of an instrument, expressed as the full-scale range divided by the minimum point of measure. It indicates how much of the instrument range can produce accurate readings, which is very important when you want to measure or control a very wide flow range without having to change instruments. Most Alicat instruments have a turn-down of 200:1 as standard (i.e. as low down as 1/200th of the full scale), although with engineering collaboration and PD²I tuning this could be extended even further. As with multi-gas capability, the benefits are again significant: fewer instruments are required to cover a wide measured flow regime, and this results in cost savings for the user.

 

As a result of over two decades of development and innovation, a range of useful flow and pressure measurement and control devices has been established that, at their very core, have been designed to help the user make their life and work easier. This innovation will never stand still, and Alicat would welcome the opportunity to assist with any challenges you face and attempt to solve the impossible!

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Improving flow data with faster flow measurement

Our world is moving faster and flow processes are not immune to this. Newer industrial communications protocols can deliver flow data from hundreds of flow meters in less than a second. This increased speed of data acquisition can improve your process, but the speed of your flow sensor can improve the data itself. In this post, we’ll take a look at two examples of how Alicat’s sensor speed can make your flow data better.

Fast flow totalization of transient flow events at oil and natural gas wells

When you need to know the total amount of a gas that has flowed, instead of just the live flow rate, the measurement speed of your flow meter becomes much more critical. If your gas or liquid is already flowing, a flow totalizer can start and stop a timed measurement to take a sample of the total amount flowed during that time period. However, when you need to know the entire amount that has flowed from start to finish, significant amounts of your data can be lost as your flow meter comes up to speed. One of the more striking examples of this came through a research application with the US Environmental Protection Agency (EPA).

Alicat was contacted by an EPA researcher who needed to quantify how much gas was being emitted by pneumatic controllers at oil and natural gas well pads. At these sites, the natural gas that is already present is typically used to drive these controllers, and when they actuate some of the natural gas escapes into the atmosphere. The challenge was that most of these controllers were intermittent pneumatic controllers whose actuation periods lasted just a few seconds. A previous study had used thermal mass flow meters to totalize these emissions. However, the 1-3 second response rate of these meters meant that a significant proportion of the flow data was lost as the thermal flow meter tried to catch up with the transient flow rate.

In order to preserve the greatest amount of flow data, the EPA turned to Alicat’s pressure-based laminar flow meters. These instruments measure flow rates 1000 times each second and have a pneumatic measurement response time of 5 ms. With these flow meters installed, the researcher was able to follow the precise curve of the pneumatic controller’s actuation, from its explosive opening to its sudden shutting. The response speed of the sensor itself recorded much more of the available data compared to the thermal flow meter, making these measurements more accurate and reliable. The Alicat flow meter’s sensor speed was able to improve the quality of the data that the researchers obtained. You can read the resulting paper published in Earth and Environmental Sciences.

Improving the temporal resolution of flow readings for environmental monitoring and beyond

Another example of the benefits of fast flow measurement comes from the realm of ambient air monitoring. The gas analyzers that measure the concentrations of greenhouse gases in the air we breathe must be periodically calibrated to ensure they are measuring these small concentrations accurately. To do this, air monitoring technicians use dynamic dilution calibrators to generate known concentrations of the gas that the analyzer is designed to measure. Because this process is dynamic, the mass flow controllers inside these dilution calibrators must also be calibrated on a regular basis.

As gas analyzers have become more sensitive, the dilution calibrators have added mass flow controllers with lower flow rates, typically 10-20 sccm at the lowest, in order to simulate smaller gas concentrations. In the past, a positive-displacement (PD) flow meter was commonly used to calibrate these mass flow controllers. This type of flow meter provides an averaged flow rate that is calculated by dividing the total amount flowed by the duration of the measurement, but the very low flow rates required hid some critical data. At a flow rate of 20 sccm, such a flow meter takes about 20 seconds to complete a single measurement (see this video). At 1 sccm (the lowest point in the required 20-point calibration), the measurement time is more than 6 minutes.

When a mass flow controller failed its calibration, there was no indication of what was happening to the flow rate during the long measurement, because the only recorded data came at the end of the measurement. Perhaps the flow controller was oscillating on a regular cycle, or perhaps it started out well and then got clogged. Sometimes, the fault was that the PD meter got stuck in the middle of its measurement, but there was no way to diagnose this scenario without continuously observing the meter.

Air monitoring technicians in these situations have turned to Alicat’s fast flow meters to make visible the data that was hidden from the other flow meter. Because an Alicat responds pneumatically to changes in flow rates within 5-10 ms, the technicians are able to diagnose the cause of a failed calibration. When data is captured in real time, recurring oscillations that come from an underperforming mass flow controller are easily distinguished from a clog in the flow path. Indeed, when an Alicat is connected to a positive-displacement flow meter, it can diagnose failures that result when the puck of the PD meter stutters in its cylinder or when the puck takes too long to accelerate to match the speed of the flow.

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Making distilled spirits better with Persedo and Alicat instruments

Alicat instruments are used in a wide variety of applications. We’re found in vacuum coating applications, food processing and the creation of fiber optics cabling. Alicat instruments test components to verify they are space worthy, provide flow control precise enough for even paint deposition from automated painting machines and precise enough to control propulsion on spacecraft while having no unintended recoil or counter effect from the device. With multidirectional flow control, we can mimic filling a car tire to pressure under test situations or simulate breathing. Alicat devices are built for each customer and with each application in mind making Alicat devices well suited to many diverse industries.

But in distilling and the refining of alcoholic spirits?

Yes, Alicat instruments can even make your mixed drink better. A company called Persedo uses Alicat mass flow controllers in their process that improves the quality of distilled spirits using a combination of ultrasonic energy, vacuum and extractive food grade gases.

The quality of a whiskey, vodka, rum or tequila can be dramatically improved in a matter of minutes by removing components which cannot be removed by distillation alone and by changing others in situ. Persedo uses an Alicat mass flow controller to precisely control flow rates of food-grade gases flow into their distilled spirits processing system. By passing two gases through the Alicat instrument, they are able to selectively strip off-flavors and off-odors from distilled spirits. The system has been used to process as many as 1000 spirit test samples.

“No other device offered us the cost-effective, dynamic process control capability and precise control (better than 0.5% of total volume) of flow rates made possible by a mass flow controller from Alicat,” said Greg George, the senior chemist and technology lead. “Precise measurements of volume flow rate corrected for variations of temperature and input pressure from tank gases is key to the quality control in our process.”

ALICAT MCR Series High Flow Gas Mass Flow Controller

Alicat MCR Series High Flow Gas Mass Flow Controller

Because Alicat devices can be controlled simply from the home screen or through various communication and industrial protocols, it is easy for Persedo and other customers to tie Alicat devices into the rest of the instrumentation and have them communicating through, for example, RS-232 to a computer without any additional modifications. Clear communication means speed and accuracy are increased. It is easy to make adjustments as needed, from flow rates to turndown ratios and even to the percentages of gases flowing into the system.

Challenge us with a new application or process. Alicat instruments are being used to improve outcomes in new and exciting ways on a regular basis. With a team of skilled Applications Engineers working with each customer every step of the way and a cohort of test, electrical and fluid dynamic engineers developing the next generation of our devices, Alicat devices are always evolving and moving science and technology forward.

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Flow and pressure control tailored for you

Highly customized flow and pressure control for demanding applications

You know your process. We know the parts you need to help get you there.

An Alicat PC-15PSIG-D pressure controller

At Alicat, we are not only focused on accuracy but customizability. We give our customers the best solution for their application, whether that be in a humid, corrosive or heavily regulated environment. Every Alicat pressure, liquid or mass flow controller is completely tailored to the customer’s needs, from flow rates to communication protocols.

Alicat devices are as diverse as the applications they are used in. For example, one customer needed to control pressure in a test environment to adjust humidity. They purchased this device: PC-15PSIG-D/5P, 5IN; a 15 PSIG pressure controller. For many customers, this level of customization is enough to satisfy the application needs.

However, some customers need more.

A customer called us looking for a pressure controller that could control gas at 155 PSIG and handle flow up to 5,000 SLPM. The controller needed to be placed in an OEM box system but not lose interactivity from outside of the box. Within the box, the system was set to operate at temperatures up to 70 oC, and to be consistent with the rest of the equipment the device required analog signals and connections.

They also expressed some concerns to us: the system included pressure sensitive instruments which would break above 155 PSIG. Since the supply pressure was 180 PSIG this would damage or break the instruments, so the controller needed to measure pressure precisely at these sensitive instruments to ensure the pressure limit was not exceeded. While the operating temperature was 70 oC, the storage temperature of the box dropped down to -50 oC making condensation a big concern. With previous Alicat devices they’ve purchased, they noticed that the devices retained the last setpoint in its memory at power up, which was a security concern.

The instrument we designed for this customer addresses all of these concerns and is represented by the part number below:

PCRH3-100PSIG-RD-REMOTE-M12-40×55-SAE24-CC/CP, 5IN, RANGE (155 PSIG), P1: 180 PSIG, FLOW (5000 SLPM), GT[1], PUSP: 0, RD: 1.5’, REM: 1’

Now, this might look a lot like alphabet soup, but every letter and number lets us know exactly what this Alicat will look like.

Alicat PCRH3-100PSIG-RD-REMOTE high flow pressure controller with remote sense port and panel-mounting

Let’s walk through the part number:

High-flow pressure control: PCRH…40×55…P1: 180 PSIG, FLOW (5000 SLPM)

The first letters, simply put, designate that the device is a pressure controller, shown as PC. The RH afterwards means that this device has a pair of Rolamite valves in Hammerhead configuration. This allows for 5,000 SLPM high flow capacity. Hammerhead valves open and close simultaneously which doubles the surface area of the valve orifices, allowing more flow. Additionally, we built the valves with a custom size of 40×55, 40 being the orifice size (0.040”) and 55 being the number of holes in the Rolamite hole pattern. This specific hole pattern was determined to afford the greatest control across the expected range of inlet pressures (P1: 180 PSIG) and desired maximum flow rate (FLOW: 5000 SLPM).

Remote pressure sensing: 3

The customer wanted to maintain pressure after a delicate system of other instruments, but needed to regulate the airflow before it reached this system. The 3 signifies a remote sense port, which allows such pressure controllers to sense flow in a different area than where the valves are controlling the flow. This system is ideal in applications with limited space because the valve does not need to be located where pressure is being measured.

Customized pressure range: 100 PSIG…RANGE (155 PSIG)

The maximum pressure that the customer intended to control was 155 PSIG, so we modified the sensor range from the 0-100 PSIG stock sensor range to 0-155 PSIG.

Designed for panel-mounting: RD-REMOTE…RD: 1.5’, REM: 1’

This pressure control system was located inside of a box, but needed to be controlled from the outside. A remote display, noted as RD, allows the display to be mounted outside of the box, giving user access to all of the functions inside. RD: 1.5’ is the length of the cable that connects the remote display to the rest of the controller. The remote display was tested to withstand temperatures down to -50 oC, the lowest anticipated storage temperature.

With operating temperatures within the boxed system as hot as 70 oC, a REMOTE electronics package was specified. In high temperature scenarios which would damage the standard electronics, we separate the sensor assembly from the rest of the electronics package, so only the sensor interacts with high temperatures and the electronics are kept safe. REM: 1’ is the custom length of the cabling needed to connect the electronics to the sensor and flow body of the device.

Locking industrial connector: M12

The customer requested a locking M12 electrical connector to keep their system from coming unplugged inside the box.

Coated to protect against condensation: CC

Moving from the -50 oC storage temperature to room temperature would sometimes lead to condensation within the system, and this could short out the electronics. To prevent this, we added a protective conformal coating (CC) on the circuit board to protect against any condensation.

SAE24 fittings

The customer was already using SAE24 threaded process connections, so we matched it.

Mismatched analog signals: CP, 5IN

Another customization for this device is a mismatched analog input and output: a 4-20 mA output pressure data (CP) and a 0-5 Vdc setpoint input signal (5IN). Typically customers use an input and output that match, but this customer needed a mismatched setup to make this pressure controller work with their existing system signals, including a PLC that has an output of 0-5Vdc.

Remote analog tare: GT[1]

Because the customer was not using a digital interface for communications with the PLC, they needed a way to remotely tare the controller using analog signals. To satisfy this need, we designed this device to be tared by grounding Pin 1 of the M12 connector.

Preconfigured setpoint: PUSP: 0

To avoid revealing potentially sensitive information, this pressure controller will always bring up a setpoint of 0 PSIG (PUSP: 0).

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Tough environments call for tougher instruments

Alicat instruments are built specifically for the conditions under which they will operate and the environments where they will be used, according to each customer’s needs. We work directly with customers to understand the stressors that will be placed on the instrument to ensure that every Alicat is up to the challenges they may experience in the field, lab or factory. Because the best repair is the one you never need, Alicat has a number of options to keep your process flowing smoothly.

In a precision test setting, it is unlikely that errant particulates, changes in ambient conditions or back flow of water will ever reach instrumentation. But Alicat instruments are often used far from the clean room. They are used to calibrate air monitors where the weather is a factor. They are used to maintain pressure and control gas mixtures in bioreactors, where cleaning means running the risk of splashing instruments. Some processes require the use of gases far more aggressive than air and other such nonreactive gases.

Humidity

In ambient air monitoring applications, humidified air can make it difficult to achieve the required accuracy in the field, especially when it is hot and humid. That is why we developed the FP-25. This flow meter incorporates a live humidity sensor that ensures accuracy of measurement at any temperature and humidity.

Recently we worked with an air monitoring customer who needed to control the flow of ambient air in humid areas at a high level of accuracy. We developed a flow controller that uses the same internal relative humidity sensor and software to correct readings based on relative humidity that we use in the FP-25. This allows for accurate sampling of ambient air as temperature and humidity change.

Water

Water outside the process line can cause issues as well. While some solutions might include creating some sort of protective box around process control instrumentation, or simply placing a plastic bag over the equipment and hoping for the best, we can build units to be rated up to IP66. Because our gas flow bodies are the same as our liquid flow bodies, a little water in the system won’t cause complete failure of the device, provided that it can be dried out later. Additionally, we have a conformal coating option to protect the interior electronics for situations where changes in temperature can cause condensation. Rain, back splash from a hose or conditions that might lead to condensation on or within the instrument are non-issues for Alicat instruments equipped with these options.

And if water or other damaging conditions are anticipated to a point where the electronics are at risk of damage greater than what can be protected with an IP66 rating or coating, we can build the device with the sensor and the electronics package as a separate remote option. This option is most frequently used in high heat environments, but can efficiently remove the more sensitive electronics away from wet conditions.

Corrosive Gases

Some processes throw more at the device than the forces of Mother Nature, and not all gases are as gentle as air, nitrogen or other common gases. Many customer processes require corrosive gases like ammonia or sulfur dioxide that could cause damage to the instrument. Depending on the gas being used, we can use FFKM or EPDM elastomers and stainless steel components. For some applications, we can customize from there, too. Our S series instruments are built with 316L stainless steel sensors, and in many cases the flow bodies and valving can also be ordered as 316L.

Hazardous Environments

For processes and environments that are potentially explosive, most Alicat instruments can be built with a CSA Class 1 Division 2/ATEX Zone 2 area certification. These instruments can be used in oil and gas applications where exposure to combustible gases is possible.

Your process can be messy, rough, jarring and abrasive. The last thing you want to worry about is your process control instrumentation being too delicate to handle the task. That’s why at Alicat we custom-build each unit with the customer’s process in mind. These Alicats are not just built to withstand tough process conditions; they can be configured to thrive in harsh ambient conditions as well. Backed by annual recalibrations and our limited lifetime warranty, an Alicat instrument will keep your process running smoothly, even in challenging environments, for years to come.

Your process, your project and the end results are what are most important. Spend your time on the things that matter, not worrying about your instrumentation.

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Meet an Alicat: In the lab with Foose

The Alicat Touch

When you call Alicat you will never hear a robotic voice directing you to press some combination of numbers. You will never be left to navigate a frustrating menu. You will never have to fend for yourself on the phone. When you call Alicat, or chat with us online, you’ll talk directly with one of our Applications Engineers. Our Apps Engineers, as we call them, each have unique backgrounds in scientific and technological fields. And, of course, they know the ins and outs of all our instruments.

Alicat is able to produce highly customized instruments with some of the shortest lead times in the industry in part because our Apps Engineers are multidisciplinary experts and are very familiar with our mass flow and pressure controllers. They are always ready to jump up and head to the production line, engineering or test lab to work out the best solution for each customer – fast.

With hundreds of variations of mass flow and pressure controllers and just as many interesting and varied uses needing just as many interesting solutions, some of our Apps Engineers spend their time working out solutions as much as they do talking with customers. This is to everyone’s benefit because it can lead to improvements to devices and new ways applications to use an Alicat.

One Apps Engineer, Foose, is often in the test lab, surrounded by tangles of wires, equipment and devices. For every minute he spends on the phone with customers, he spends one in the lab solving their problems.

Foose is a chemist with the heart of a tinkerer. Like most Alicats, he is solution driven. He not only identifies the source of the problem, but the cause to ensure that he can help customers purchase, troubleshoot or fix their device – not just the right way but the best way. He’s so good at fixing things that when one of us is having an issue with the new demo for an upcoming trade show, setting up the equipment for a presentation or fixing the electronics in an old arcade game, we all go to him.

I recently sat down with Foose to ask him a few questions:

What is your favorite part of the day?

Since we are based in Arizona and are ahead of the clock from many of our customers, the later part of the day is when I have time to expand my knowledge of our own products and ways they are used. Currently the bulk of this special projects time is spent learning to program PLCs and use automation software so that I can better troubleshoot our devices and understand how our products interact with industrial systems.

What is the most interesting project you have worked on?

My favorite application that I’ve worked on was a research project designing an olfactometer to test a dog’s ability to distinguish very low concentration odorants. I love animals, and the application was memorable and unique. The basic parameters of the system were already understood by the customer, but I was able to show how our very high turndown ratios could allow a handful of dilution steps to deliver accurate odorant concentrations across many orders of magnitude, how the customer could improve repeatability with active backpressure control and how we could customize the valve configuration to reduce system purge time between experiments.

How are you Alicat fast?

I’m good at troubleshooting. I always want to know more about how devices are built, how they are used, how they perform and how they break.  Sometimes this means I can save customers expensive downtime by helping them identify complex problems and fix equipment in the field without ever having to return a device to Alicat. I often spend time in the lab making short instructional documents for customers who need to modify or configure our devices in a certain way. For example, one time a customer broke the front display of their Alicat and wanted to return it for repair. I know that replacing the front display cover and membrane switch is a fairly simple task requiring only a few minutes and some simple hand tools but learning how to do it over the phone would be harder than following a written guide with pictures. I created a small guide on how to do this simple repair, overnighted the customer a membrane switch and the customer’s process was back up and running in less than 24 hours.

Alicats, from the Apps Engineer you talk to on the phone when you place your order, to the Calibrator in production, are all working to make every instrument we sell exactly what each customer needs, as fast as possible. All while…

  • Maintaining NIST-traceable: +/- (0.8% of the reading + 0.2% of the full-scale range) on mass flow controllers and NIST-traceable: +/- 0.25% of the full-scale range for pressure controllers.
  • Collecting data fast with response time of 50-100ms on readings.
  • Being easy to use, right out of the box – with straightforward plug and play set up, front display controls and clear data readings – so processes aren’t held up by installation.

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Differential pressure-based laminar flow measurements are faster than thermal

Mass flow controllers need to be accurate and reliable. And thermal-capacitance based instruments can meet those requirements. But when a process or experiment needs high accuracy, faster response times and flexibility, thermal can come up short. At Alicat, our MC-series mass flow controllers use differential pressure-based laminar flow measurement. By forcing the flow to be in a laminar state, we can use Poiusuelle’s equation to calculate the volumetric flow rate as long as the temperature, pressure and gas, measured by the device in real time, are known. Allowing the user to enter in the standard (or normal) temperature and pressure, an Alicat translates volumetric flow into mass flow rate and even a true mass flow rate in mass per unit of time (e.g., kg/s). If the gas’s viscosity as a function of pressure and temperature is known, then Alicat instruments can measure it.

The Slow Way

Compared to an Alicat Laminar Flow Differential Pressure instrument, thermal bypass flow instruments are slow. One of the most inconvenient requirements of thermal bypass flow instruments is the lengthy warm-up time to reach thermal equilibrium: 30 minutes is not unheard of, during which time the flowing gas is running and wasted. Once running at thermal equilibrium, the device’s ability to respond to changes in flow is subject to thermal hysteresis, which is a delayed response of the sensor, as compared to a pressure differential sensor. Thermal bypass flow instruments need to be calibrated with the actual gas in the end use application. Because every gas has a different thermal capacity, if they aren’t calibrated to the gas in use, they will need to have their flow values altered by a correction factor or K-factor. K- factors introduce a degree of uncertainty to the measurement, decreasing accuracy.  Another drawback is that the most common turndown ratio is 50:1. While this is a decent turndown, it severely limits the usable range of the device.

The Alicat Way

Pressure sensors are built on diaphragms that are incredibly sensitive to changes, making them among the fastest sensors available. Alicat mass flow controllers use this different type of sensor to fill a need for speed and responsiveness in the industrial and the analytical worlds. By laminarizing flow, Poiseuille’s equation determines mass flow from differential pressure, viscosity, temperature and pressure.  We’ve preprogrammed every Alicat mass flow controller with viscosity and compressibility data for up to 130 gases and gas mixtures, to give you accuracy without K-factor uncertainties.

Because pressure equilibrates faster than temperature, differential pressure sensors don’t require the same warm-up that thermal sensors do. Differential pressure equilibrates so quickly that responses to changes in flow as fast as 10ms can be expected. Paired with a control valve, the control settling time can be similarly fast, between 50ms and 100ms is common and some applications achieve 20-50ms.

Standard turndown for Alicat units is 200:1, allowing a greater controllable range than thermal units; thousandths of a standard cubic centimeter per minute are readable on the instruments with the lowest flow ranges. At the other end of the spectrum, we also offer one of the highest full scale rates offered for an inline flow controller—5000SLPM.

Using differential pressure-based laminar flow measurement, an Alicat mass flow controller can change gases accurately, accommodate a wider flow range, and operate faster than thermal technology.

  • Turndown ratio: 200:1
  • Standard accuracy calibration, NIST-traceable: +/- (0.8% of the reading + 0.2% of the full-scale range)
  • Repeatability: 0.2% of the full-scale range
  • Typical control response time constant: 50-100ms (as low as 25 ms with PID tuning)
  • No warm-up time required

One Device to Rule Them All

Alicat devices are flexible, not only in the lab where you can control and change settings directly from the device display, but on the factory floor where many instruments can be controlled simultaneously from one central PLC. Each device is made custom for the customer’s needs. And, as those needs change and evolve, we can recalibrate and even reconfigure existing devices, with no need to replace a device every time a new update comes out or the process changes.

Alicat’s unique way of measuring flow makes it gas independent and faster than thermal-based instrumentation. Pressure measurement also leads to our 200:1 turndown ratio, allowing for a larger range of flow rates in a single device. And device flexibility means that an investment in an Alicat device, with its lifetime warranty, will keep measuring a variety of flowed gasses to a high degree of accuracy over time and across evolving experiments processes.

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Two pressure controllers are better than one in extreme environments

Some industrial and analytical applications, especially applications with mixed phase fluids, corrosive media or extreme temperatures, can be better handled by purely mechanical classic industrial regulators than electronic pressure controllers. Purely mechanical regulators don’t usually have the same susceptibilities to these types of conditions that electronic pressure controllers do.

However, there is a trade-off. While the process gains toughness, it loses high speed control, user friendly electronic interface, onboard PID and the accuracy and resolution of pressure control that make Alicat electronic pressure controllers highly accurate, fast and easy to use.

Why don’t we have both?

One of Alicat’s partners, Equilibar, is a manufacturer of high performance mechanical industrial back pressure regulators. The Equilibar back pressure regulator (BPR) features a flexible diaphragm as its only moving part to provide frictionless, stable operation. Equilibar’s dome-loaded, multiple orifice design offers precision, as well as compatibility with mixed phase fluids, corrosive media and extreme temperatures.

One requirement of the Equilibar back pressure regulator is that a reference pressure be provided to the “dome” in order to tell the larger regulator what back pressure to control to.  This can be handled in a number of ways:

  1. Using a sample pilot pressure pneumatically routed to the dome. The limitation here is that the setpoint is subject to change as the pilot pressure changes.
  2. Pressure is provided to the dome with a mechanical pressure regulator.  While this may do a fine job in some applications, a mechanical regulator feeding the dome on another mechanical regulator still does not attain the precision and functionality of an electronic solution.
  3. Utilizing an Alicat Dual Valve Pressure controller (PCD) to perform the precise pressure manipulation of the diaphragm inside the dome.  Alicat’s sub 100ms control speeds and precision of control allows high resolution control of the Equilibar BPR diaphragm control mechanism. Alicat’s PCD series, optimized for closed volume pressure control, essentially becomes the brain of the Equilibar BPR, giving end users the ability to automate control through a computer terminal– or simply with the push button display on the Alicat PCD.

Alicat and Equilibar

When Alicat and Equilibar began working together, Equilibar had been looking for a solution to precise closed-volume pressure control for their domes that could control the pressure on the diaphragm reliably from 0 to 3000PSIG. This would give The Equilibar back-pressure user who needs 3000PSIG back pressure control, the advantages of using an electronic pressure controller.

The Equilibar BPR and the Alicat PCD3 3000 both have high resolution, so each is able to take advantage of the other’s high precision control.

  • Alicat’s sub 100ms control speeds and precision of control allows high resolution control of the Equilibar BPR diaphragm control mechanism.
  • Equilibar’s unique construction using a thin, supple diaphragm as the only moving part delivers near-zero hysteresis and will accurately repeat the high resolution pilot signal from the Alicat into a corresponding high resolution pressure within the application.
  • Alicat’s active PID control and dual valve system allows for fast and adaptive response to changing operating conditions without the need for user interference or adjustment.
  • An Equilibar back pressure regulator allows the Alicat to control pressure in applications with extreme temperatures, severe chemistry or mixed phase fluids because the Equilibar will faithfully reproduce the pilot pressure signal in these complex process conditions.
  • The Alicat PCD series allows users to automate communication. And adds the features of a lab style instrument to the Equilibar back pressure regulator.

Sometimes two technologies are better than one. Pairing Alicat’s feature-rich electronic pressure controller with Equilibar’s resilient mechanical pressure controller allows for the best of both worlds in processes that require accuracy, speed and durability.

 

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Alicats provide accuracy and repeatability to valve testing in space exploration

Exploring the final frontier is part of a normal day at Alicat. We work on a variety of aerospace applications, projects and experiments that help keep pilots safe, put satellites into space and launch rockets. Alicat works closely with customers in these fields to understand their problems and find straightforward solutions.

Aerospace is a diverse market that utilizes flow and pressure instrumentation for a wide variety of tests and processes. Alicat has worked on projects that:

  • Ensure the oxygen masks in commercial and military airplanes flow the correct amount of gas and meet safety regulations.
  • Provide liquid mass flow controllers capable of flowing water for cooling systems in propulsion systems.
  • Control the lift of high-altitude balloons used to study and understand weather patterns and in other experiments.
  • Assist with the pitch, roll and yaw on a satellite using pressure controllers.
  • Combine mass flow and pressure control to replicate the atmospheric conditions on Mars to create an environment to test instrument performance in harsh Martian conditions.
  • Leak test and characterize the valves that are used in rocket engines.

Leak testing and characterizing the valves that are used in rocket engines.

Leak testing in a lab environment on Earth, where pressure and mass flow controllers are installed into test stands, mass flow and pressure devices do very well with the low leak rate volumes and at low pressure.

However, going to space is a little more complicated. Most rocket components must be tested to higher pressures, similar to those found in the oil and gas processes.

The equipment typically used to do this kind of testing is a dome-loaded regulator. They are used to control the pressure in these tests because they can handle high pressure and the high flow rates experienced in these processes. However, while dome-loaded regulators can handle the pressures they are working with, they suffer from hysteresis. This is due to the mechanics of the valve spring and the behavior of the valve changing depending on its current position and whether it is opening or closing. This can result in a non-repeatable process.

The Alicat solution

3000 PSI Pressure Controller

3,000 PSI Pressure Controller

To avoid hysteresis and ensure that the process is repeatable, Alicat has provided the high pressure rated dual-valve pressure controllers (PCD) that can tolerate pressures up to 3,000 PSI. To do this, the PCD uses a proportional control valve that is controlled by onboard PID tuning of the device that limits the repeatability issues found with other pressure regulators. PCDs can also be configured with a remote pressure sense port to measure the pressure at the location of regulation to reduce delay and speed up the response time of the system.

To characterize and leak check the valves used for space flight, the high pressure PCDs are used to control static and flowing processes and are paired with an Alicat flow meter. While the PCD is controlling the high pressure on the inlet port of the valve or other component, a Whisper low pressure drop meter is installed downstream of the valve to capture the leak through the valve. Since the valve is exhausting to near atmospheric pressures, a non-restrictive flow device is required to minimize back pressure in the system. The Whisper can also easily switch between N2 and He gas, the most common gases used in these tests, and maintain its accurate flow readings. Switching between gases on the fly is simple through a communication protocol from the devices to a computer or directly from the device’s front panel display.

Meeting the industry where they are: process ports

To meet the needs of this industry, Alicat pressure and mass flow devices can be configured with AS5202. Aerospace Standard and Medium-Pressure process ports are available for easy integration into a test stand. This type of porting has become more common in the aerospace industry and are available on Alicat devices.

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com

Alicat mass flow controllers save customers money without sacrificing accuracy, reliability or functionality

Andy is the sales director at Premier Control Technologies, a UK based process control technologies and products distributor which represents Alicat products.

Andy has over 30 years of experience with pressure and flow control instrumentation.

He can be reached at andymangell@pctflow.com.

 

My Grandad M. used to tell me: “In this life, my lad, you can’t get something for nothing!” He was, of course, referring to the benefits of hard work and his belief that if something is worth having then it is all the better for having worked hard to earn it. Having grown up with this ethos, and being a true Yorkshireman myself, I am not capable of seeing this as anything other than true.

Consider the following project:

We want to control four gasses at a high level of accuracy with a span from 0.1 millilitres per minute to 800 litres per minute. While controlling within that range, we also need to measure the pressure and temperature of each of the flowing gasses. Not a simple project, to be sure, but not outside the realm of possibility.

Let’s break down the instrumentation needed for this project. The average mass flow controller has a turn-down ratio of 50:1 of the full scale range. If our total measurement span is 0.1 millilitres per minute through to 800 litres per minute, we’re going to need a minimum of five MFCs. On the other hand, Alicat MC series mass flow controllers have a turn-down ratio of 200:1. With full scale of 20 milliltres per minute, 4 litres per minute and 800 litres per minute, a quick calculation shows that we’ll only need three Alicat instruments to perform the same task. Saving ourselves the need of two instruments is handy but it isn’t something for nothing yet.

Alicat's Gas Select menu

Alicat’s Gas Select menu

The second piece of our project is the gases. Let’s say we need to flow four gases: nitrogen, carbon dioxide, argon and hydrogen. Most bypass MFCs are limited by precalibration per gas and require conversion factors between these gases. Unfortunately, our gas control project needs the ultimate in accuracy. The measurement uncertainty introduced by the k-factors is just too great. Argon alone can have a conversion factor error of as much as 2.8% above standard calibration uncertainty. So now we need separate instruments for each gas to get reliable data. Four gases times five instruments and our cart is getting full. Even if just flowing one instrument at a time, a total of twenty instruments would be required to cover the whole spectrum.

Alicat MFCs are preset with over 98 gases and gas mixtures – all certified within the standard calibration accuracy. So for the same process as above, flowing just one instrument at a time, would still only require three instruments needed to cover the whole spectrum. Assuming a cost of £1000 per MFC, we can see that if we used average instruments, our costs would be at least £20,000. And with Alicat devices? A much more palatable £3000.

But controlling the flow is not all we need our MFCs to do. We also need to measure both pressure and temperature per gas. A pressure transducer, a temperature transmitter, the fittings required, the cables and installation costs could amount to at least £400, probably more. Times four.

Not so with an Alicat. Their mass flow controller includes pressure and temperature measurement so there is no additional cost whatsoever. Plus, with the push of a couple of buttons, it can be reset to perform the opposite action and control the pressure whilst measuring the flow.

With our average MFCs we have to have a system to control the two dozen devices we’d need for this project. An Alicat device, on the other hand, is easy to integrate into a preexisting setup with analog or serial communication protocols, but if we didn’t have a system in place, we can control our three Alicats right from the front screen of the devices.

Pulling all of the above together we can see that for our gas control project, using the average MFCs will need at the very minimum an investment of £20,000 for the instruments themselves, £1,600 for pressure and temperature measurement and £2,000 for a readout and control module. A total of £23,600. By using Alicat instruments an investment of £3,000 would achieve the same results.

All Alicat instruments come with the industry’s only lifetime warranty.

It’s simple maths. Even Grandad M. would agree that Alicat instruments have so many additional features and capabilities you get, if not something for nothing, so much more for so much less.

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: sales@sensorguys.com Website: www.sensorguys.com