Understanding Pressure in Vacuum Instrumentation

A review of the common terms and definitions of vacuum and pressuremeasurement including ambient pressure, differential, gauge and absolutepressure.

 Understanding Pressure in Vacuum Instrumentation Article

Digivac's solution to controlling vacuum

A review of automated methods for vacuum control that range from powercycling a vacuum pump to proportional valve control.

Digivac's Solution To Controlling Vacuum Article

Physics of Vacuum gauge sensors and manometers

If you haven't been in the vacuum industry for many years, you might want to consider browsing wikipedia or another source on some of the basic types of pressure and vacuum measurement .  Digivac uses a variety of it's own sensors, as well as sensors from a third party.  Digivac has perfected the use of thermocouple vacuum gauge tubes, which is similar to a pirani gauge in theory.

Terminology used by Vacuum vendors

The most important thing that any vendor can offer you is the ability to solve your vacuum measurement or process control challenge in a quick, efficient and cost effective manner. Therefore, it's important to understand industry standard terminology.

Vacuum Gauge

A Vacuum gauge is a device that measures the pressure, or that pressure below atmosphere.  Digivac uses this term to refer to the product that you buy that includes all of the components needed to measure vacuum.  This includes a vacuum gauge controller, the thermocouple vacuum gauge tube.  Sometimes vendors may refer to the transducer (such is the case with some capacitance manometer vendors) as a "vacuum gauge."

Vacuum Gauge Controller

A vacuum gauge controller is the device that translates the vacuum sender, the vacuum transducer, the thermoucouple vacuum gauge tube or other tranducer to a meaningful output.  For example, Digivac makes Vacuum gauge controllers for capacitance manometers and other types of vacuum sensing devices.

Thermocouple Vacuum Gauge Tube

A thermocouple vacuum gauge tube is a tranducer that senses vacuum by leveraging the principal of seeing how a wire changes temperature as vacuum is changed.  Common vendors of  thermocouple gauge tubes are Varian, Fredericks, Hastings and VGT, to name a few.  This inexpensive vacuum sensing technology enables Digivac to provide significant value to their vacuum instrumentation.

Vacuum Controller

A vacuum level controller is a device that holds the vacuum of a system at a particular vacuum set point.  Often this is achieved manually by a person connecting a vacuum gauge to a system, and manually cracking a vacuum valve open to achieve the desired vacuum.  A vacuum level controller device like the Digivac Model 450 can achieve this in the Torr range with far less human intervention. 

There are several ways to choose vacuum gauges.  We find that in some industries there are specific types of vacuum instrumentation that are typical.  We share our experience with you to help guide your choice of vacuum gauge controller and thermocouple vacuum gauge tube.

Refrigeration Vacuum gauge controller and thermocouple vacuum gauge tube

The refrigeration industry measures vacuum in microns, and wants a rugged dependable gauge to measure the evacuation of a refrigeration system.  One useful feature for a vacuum gauge used in refrigeration evacuation is the ability to read up to atmosphere.  A vacuum measuring instrument that measures all the way up to atmosphere enables the user to quickly troubleshoot basic problems such as a leaky system or open valve. The refrigeration industry often prefers our Digivac Model 200 because of it's convenient size and it's rugged design.  Our Vacuum gauge comes with everything you need to start measuring vacuum in your refrigeration system. 

Neon Industry Vacuum measurement and Neon Tube Thermometer

The Neon industry can benefit from 3 products we provide: 2 Vacuum gauges and a Thermometer. 

1. In Neon applications you need one gauge that confirms that you have evacuated the Neon tube; that is if you have just air in the tube at a vacuum of about 7 microns.  For this application we recommend a Digivac Model 45 Battery operated Vacuum Gauge with a Fredericks thermocouple vacuum gauge tube.  This vacuum gauge combined with the thermocouple vacuum gauge tube has the quality of being very durable and immune to the flashback exacerbated by the very high voltage necessary to drive the bombarding current and the corrosive environment.
2. Next we recommend a Digivac Neon Thermometer that will enable you to accurately measure the Neon tube, avoiding the need to "guess" at what temperature you are at.  Our unique ultra fast thermocouple probe allows you to easily attach to the neon tube and allows you to follow manufacturers temperature recommendations exactly during both the evacuation and fill process.
3. Last, we recommend a Digivac Model 100LED760  which enables you to accurately measure the filling pressure of the neon and argon you are putting back in the tube.  This gauge needs to read very accurately at 27 Torr, and this gauge reads from the micron readings all the way up to 760 Torr (atmosphere.)

An advantage of having battery powered instrumentation during the evacuation process (products 1 and 2 above)  is to avoid the possibility of the high voltage finding it's way through the instruments to ground.  Having battery powered instrumentation avoids this path to ground and increases the longevity of your vacuum instrumentation.

For a quick overview on Neon Processing, click on Neon at Wikipedia.

Cryogenic Industry Vacuum Gauge Controller

In the Cryogenic industry, we find that hastings vacuum gauge thermocouple tubes are often found permanently mounted in cryogenic vessels.  Often, it might make sense to have a battery operated Vacuum Gauge that enables you to walk along a cryogenic vessel, and measure the vacuum at that point.  The range of interest is in the 10mTorr range.  We have a variety of gauges that enable you to measure vacuum with hastings tubes, and our most popular products for this application is the battery operated Model 100 Hast Batt for battery power, and the Model DVG-6 for the panel mount AC version. 

Pharmaceutical industry Vacuum Gauge controller and Vacuum controller

We find that many in the pharmaceutical industry use vacuum gauges, vacuum controllers and vacuum sensors to measure their system vacuum in Torr or mTorr.  The two popular vacuum instruments that we see our pharmaceutical customers choosing is the Model 200 as a vacuum gauge and a vacuum transmitter, and also a Model 450 vacuum controller which maintains the vacuum of a flask or closed sysem in the Torr range.  For readings required in the Torr range, we see our pharmaceutical customers choosing our Model 100LED760 .

Semiconductor manufacturing industry Vacuum Gauge controller and Vacuum level controller

We find that many in the semiconductor industry use vacuum gauges, vacuum controllers and vacuum sensors to measure their systems under vacuum in Torr.  The two popular vacuum instruments that we see our pharmaceutical customers choosing is the Model 100LED760 as a vacuum gauge and a vacuum transmitter, and also a Model 450 vacuum controller which maintains the vacuum of a flask or closed system in the Torr range. 

itchy skin

Custom DIGIVAC pressure and vacuum products are used in virtually every walk of life.. in manufacturing, in refrigeration, pharmaceutical and the recreational industry.  If you are looking for a product to act as a controller for an existing or preferred sensor, let us know how we can help.   Some examples:

• Digivac Model 252 capacitance manometer gauge controller
• Digivac Model 259 Alcatel ACC1009 gauge controller
• Digivac Model 100LED40 used to measure from 1 to 40" of water with tenths accuracy
• Digivac Model 443 tripple gauge controller used to display readings of 3 Alcatel ACC1009 gauge controllers and graph the result on a PC.
• Model 100LED29.9 to measure pressure below atmosphere in inches of mercury

Chances are we've seen your problem before and we have a product on the shelf we can ship you! 

Benefits of making DIGIVAC your OEM for vacuum instrumentation

The engineers at DIGIVAC are experts in the vacuum technology field.  We've perfected the use of low cost thermocouple vacuum gauge tubes to achieve wide vacuum ranges from 1 micron all the way up to atmosphere creating a high value product.  We have current relationships with large vacuum gauge manufacturers to design and build high volumes of product for use in a variety of product lines.  Let DIGIVAC worry about the design, manufacture and test of your vacuum gauge products.  We offer a high value product with predictable lead times and a business model that allows us to scale to any quantity quickly and efficiently.

DIGIVAC Electronic Controls

We are the original equipment manufacturer for many different type of electronic controls from the simple to the very complex.  DIGVAC makes electronic controls for many applications including handheld DC motors, chillers/cooling units, freeze dryers and industrial ovens .. just to name a few.  We can take an industrial need from concept to volume manufacturing in months.  We can apply our existing OEM product knowledge of industrial systems, controller and software technology to your meet your needs.  Contact us about the control need that you'd like filled.