Most of our calibrators are designed to use standard replaceable Alkaline batteries. You know, the ones you can buy at the corner store. That’s a good choice because of the relatively high power density and mostly flat discharge curve of these cells. They start out with a high terminal voltage (1.5 V  or more). A really strong point for these batteries is the long shelf life. If you don’t use your calibrator much, that would be a good reason to use Alkalines. New ones typically have a shelf life of 3 years or more.

On the flip side, if you are a heavy calibrator user, rechargeable batteries, especially very high energy density Nickel Metal Hydride batteries would be a good choice. What is meant by high energy density? Energy in the battery world is measured in Amp hours. For small batteries, it’s most commonly milliAmp hours.

AA Alkaline batteries are typically rated at 2000 mAH. They’re small so they have a high density. Even inexpensive Nickel Metal Hydride batteries now come with 2700 mAH ratings. They have another plus. Although the battery terminal voltage for NiMH batteries starts out at 1.2V, the discharge cycle is extremely flat and the internal resistance is lower. They work right up to the end, so to speak.

You may get as much as 40% more usage from the NiMHs than the Alkalines when they are fully charged. But, that’s the rub. The shelf like of rechargeable batteries is not good in 2 ways. One, they need to be charged regularly, and, two, they will lose their charge when not being used. Infrequent users may find their rechargeable batteries are dead just when they want to use their calibrators.

Here are the tips in short form.

1. If you use your calibrator everyday and use it a lot, consider switching to rechargeable batteries. They are reliable and efficient and you’ll help save the planet. You will recharge your calibrator every night.
2. If you have poor access to replaceable Alkaline batteries, also consider changing to rechargeable batteries. Just remember to keep them charged.
3. If you don’t use your calibrator much, stick with the Alkaline batteries. They’ll be ready when you are unless you have situation 2 above. In this case, if you do use rechargeable batteries, just remember to charge them once a week or at least a couple of times a month.

The most exceptional thing can often be the simplest thing, too.

A lot of companies have some sort of “open door” policy that allows employees to access the higher ups. At Martel, that means anyone can walk in Tom’s office and let him know what they are thinking, ask questions, whatever.

A few employees are fairly regular visitors who come to him with ideas for handling problems and the like. I guess the thing that’s surprising is that many employees wouldn’t even consider making a trip to the corner office. I’m sure they’re being held back by that old thing “tradition” that says a trip to the boss’s office is like a trip to the principal’s office at school. You only do it when you’ve been bad.

I also know that in some companies, the peons are not allowed to socialize with the elite. At really large companies, that almost makes sense. Bill Hewlett and David Packard (HP founders) made the reverse trip with management by wandering around. They did it just so they could see for themselves (and hear for themselves, too) exactly what was really going on in the company.

So, I think our little company is pretty exceptional to have employees AND management that make it a point to communicate in such a basic way.

Wow! It’s one new thing after another…

Most of our calibrators use replaceable and convenient Alkaline batteries either AA or 9V types. They’re readily available in all markets. But, for reasons of economy or ecology, some people prefer rechargeable batteries. We’ve sold these as an option for everything we make.

NiMH Battery Kit

Now, we have a new purpose designed and made battery pack for the BetaGauge 330 Pressure Calibrator. Because of its built-in electric pump, the 330 uses (8) AA cells. Previously, to use rechargeable batteries, you had to take out all 8 cells, put them in one or more chargers and then reinstall them. That’s a bit user unfriendly. Being the smart and friendly people we are, we decided to create a sealed battery pack with external charger to make this quick and easy.

Our new battery pack also offers a bit better performance with a total of 2.7 Ah available energy against 2.0 Ah from the Alkaline cells. Since the Nickel Metal Hydride (NiMH) batteries have a lower internal resistance than Alkalines, they are able to squeeze more out of each charge, too.

A fully depleted pack can be recharged in about 2 hours and can be expected to provide up to 400 complete pump cycles from 0 to 150 PSI.

The charger is a universal type (100-240 VAC, 50/60 Hz input) that comes with a set of snap in adapters for use with any type of mains connection outlet.

In a recent post, I said that one of the important features in a calibrator is flexibility or versatility. You might say it’s the Swiss Army knife (a registered trademark of Wenger S.A. and Victorinox A.G.) effect. I know that sometimes mashing things together makes a whole that’s a lot less than the sum of its parts, but…

For calibrators that’s not the case. In fact, because they are often the most highly engineered products a company offers, multi-function calibrators may offer the best overall performance in a company’s line. There don’t really need to be too many tradeoffs.

Sure, the multi-function calibrator is likely to be larger than its single function relatives and certainly a bit more complex, but having every tool you need everytime you need it is worth it for many. Our MC-1200 has the capabiltiy of a loop calibrator (and just as easy to use), a high performance temperature calibrator (just about every T/C and RTD curve you can think of), a wide ranging pressure calibrator (29 ranges and styles of Beta pressure modules), DC voltage and frequency (with pulse train output).

That’s what I mean about versatile.

Valve Location

I’ve been posting a lot about the BetaGauge 330 lately because we’ve had a lot of new developments for it. With the revolutionary built-in battery operated test pump, it has become our flagship product. So, we spend a lot of time trying to make it even better.

The good news/bad news is that the strength of the 330 (built-in pump) is also its Achilles heel. Contamination of the pump valves will make it leak and/or not work. We considered that in the initial design and made those valves easy for the customer to access (picture at left) and clean (video at YouTube).

That, by itself, might be good enough for some.

However, we want to go even further and stop a potential problem before it even starts. In this case, the potential problem is liquid being sucked into the pump mechanism from the device under test. When this happens, you’re looking at more than just cleaning the valves. It’s time for a full rebuild, which is time consuming and more difficult.

LDT-500 Liquid/Dirt Trap

So, we’ve designed and are building a liquid/dirt trap accessory for the BetaGauge 330, The LDT-500. Beginning this month, all 330s will ship with this device as standard. It mounts on the calibrator’s pressure port between the calibrator and any potential contaminant. With its clear body, it’s easy for the technician to see when a problem might be occuring and prevent it. The LDT-500 will also be available separately for users who already own a BetaGauge 330 and want to protect it.

The design of the LDT-500 is pretty clever, too. It’s virtually tooless as it screws into the calibrator port and seals with an o-ring. No pipe sealant tape required. The open process port is Martel’s unique NPT/BSP thread for universal use. Cleaning of the LDT is tool free, too. The end caps unscrew by hand, making it easy to clean out. If needed, replacement o-ring seals are available as a maintenance kit.

We’re working on even more improvements for the BetaGauge 330, so keep in touch.

BetaGauge330

In June, we started shipping the BetaGauge 330 with available absolute pressure internal sensors. The 330 is now available with a 30 PSIA (2 barA) or a 150 PSIA (10 barA) internal sensor.

The new ranges offer the same ±0.025% of full scale accuracy (6 month specification) as the previously offered gauge ranges (30, 150 & 300 PSI).

Some of the other useful features of the 330 are

• built-in loop calibrator (input and output
• large multi-variable display
• 24 VDC instrument power supply
• automatic pressure switch test
• available gas custody meter calibration kit
• 17 engineering unit displays
• external pressure module compatible

For a surprisingly low cost in a surprisingly small and lightweight package, the BetaGauge 330 has a lot to offer.

We (people actually in the calibration industry) often hear things being called calibrators that obviously aren’t. A great example is the Emerson HART(tm) communicator. No offense intended, but these types of devices aren’t calibrators, they are electronic “screwdrivers” that enable a technician or engineer to adjust the calibration of a device.

Here are my defining points for a calibrator.

1. Can make a precision measurement or generate a precision signal (i.e., analog, not digital). Or BOTH.
2. Has a calibration that is traceable to national standards.
3. Has a known accuracy or degree of calibration uncertainty.

There is a lot that could be added to this list, of course; things such as conformance to international standards, EX ratings…

Another little list of mine is this list of characteristics that make up a good calibrator.

• Accuracy
• Flexibility or versatility
• Ease of use
• Reliability
• Ergonomics (small, lightweight, easy to read display, etc.)
• Value

To me, a great example of all of the above is the Martel BETA MC-1200 Multi-function Calibrator. It’s got a long list of features, top knotch performance and is a great deal for the money. Total cost of ownership is good because all they ever require is annual recalibration which anyone with a computer and adequate standards can do.

Preproduction Testing

In preparation for a new product launch, Martel is adding new temperature calibration equipment. The 2 major pieces are a Fluke Hart Scientific 9210 Triple Point of Water and a Fluke Hart Scientific 7341 High Precision Temperature Baths.

Here are some pictures of the new equipment, which is shown being used in preproduction testing now. By the end of our summer they will become the foundation of a production temperature calibration lab.

Hart 9210 Triple Point of Water

Hart 7341 Precision Temperature Bath

We have posted a new video on YouTube that details the cleaning process for the BetaGauge 330 pump valves.

The 330 has been a really trouble free product except that many users don’t bother to try cleaning the pump valves if they become contaminated. They end up sending it in for service that they could do themselves in about 10 minutes.

While the cleaning process is described in the user manual, a video is a better way to get the message across.

Valve contamination occurs during the normal use of the pump in many industrial environments. We designed them to be trouble free and really easy to clean.

The video shows the whole process in about 5 minutes.