Tag: standard

Standard Temperature and Pressure: What is STP?

Published on by John BallLeave a comment

When it comes to volumetric flow rates, you probably noticed the prefix of an “S” for SCFM and SLPM, or an “N” for NM3/hr.  The “S” prefix is for Standard conditions, and the “N” prefix is for Normal conditions.  For practical reasons, they are the same thing.  What does this mean? 

Let’s look at the Ideal Gas Law in Equation 1:

Equation 1:

PV = nRT 

P – Pressure

V – Volume

n – No. of moles

R – Ideal Gas constant

T – temperature

Since air is compressible, it will react in different ways.  If we keep the volume the same and lower the temperature, the gas pressure will go down.  If we keep the temperature the same and decrease the volume, the gas pressure will go up.  If we go to a higher elevation, the number of moles is reduced, which will lower the gas pressure.  With the different degrees of changes, it is difficult to compare.  So, organizations decided to place a standard on these conditions to help compare results.  The definition is referred to as STP, or Standard Temperature and Pressure. 

In most cases, the Standard Temperature and Pressure is set at 20oC and 1 atm (1.013 bar).  If we transition all pneumatic units to this condition, we can then compare the results for each product.  We can determine which units actually use less compressed air or have higher forces.  Or if we decide to use a different STP, we can do that as well as long as we use the same temperature and pressure. 

I like to think of it like an air-filled balloon floating on top of the water.  This would be the “Standard” or “Normal” condition.  As you take the balloon into deeper water, more pressure is applied to the balloon, and the volume will decrease.  This is because air is compressible.  The balloon still has the same amount of air by weight (as the volume decreases, the density increases).  If you return to the surface, the balloon will expand back to the original size.  When doing comparisons, we need to be in the same condition, or for the balloon example, it will look like the balloon will need less air at lower depths than at the surface.   

The reason for this explanation is that some competitors like to use lower pressures to rate their products.  As an example, Competitor A rates their nozzles at 5 bar (72.5 psig).  EXAIR uses 5.5 bar (80 psig) for most of our products.  By comparison, we cannot say if one unit uses more or less compressed air unless we set them at the same conditions.  The best place to compare is at a Standard Temperature and Pressure, or STP.   I go into more detail in my blog about air flows with “CFM, ICFM, ACFM, SCFM: Volumetric Flow Rates Explained”.  EXAIR offers Super Air Knives, Super Air Nozzles, and Super Air Amplifiers to efficiently blow compressed air.  So, when a company states a compressed air flow, verify the pressure and temperature at which they recorded that information.  It will help you to be more in tune with what you are getting (allow for an apples to apples comparison). If you need any help in doing comparisons, an Application Engineer at EXAIR will be happy to assist you. 

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

Photo:  balloon helium air flying bright by stux.  Pixabay license

About OSHA 29 CFR 1910.242(b) for Compressed Air Safety

Published on by Brian FarnoLeave a comment

In February of 1972 OSHA released a standard to improve worker safety when operating handheld compressed air devices being used for cleaning purposes. This directive focuses around human skins permeability. That is, if you were to take an open ended pipe that had compressed air being discharged over 30 psig it can actually push through the skin and create an air embolism.

OSHA’s Directive 29 CFR 1910.242(b)

Air Embolisms are extremely painful, and in extreme cases, can be deadly. The risk associated with an air embolism can be mitigated by following the OSHA directive and reducing the downstream pressure of an air nozzle or nozzle pressure below 30 psi for all static conditions. Dead ending is when the passageway for the air becomes blocked and turns a dynamic flow of air into a static flow. This is in the event the pipe, nozzle, lance, etc. becomes blocked by a human’s body. This is a directive that all Intelligent Compressed Air® products from EXAIR focus on meeting or exceeding.

Our Air Nozzles and Jets video shows a great depiction of how this can be achieved with our engineered design of nozzles. The recessed holes and the fact that there are multiple passages for the air to exit are easy to see on the nozzle. Products like the Super Air Knife may not be so easy to see but the way the air knife cap overlaps prevents the Super Air Knife from being dead ended in the event an operator comes into contact with the discharge air.

Even though this directive was created in 1972 it continues to be at the forefront of industrial environments. I have even been to a custom artwork facility that was effected by this standard because they would use a handheld blowgun to remove dust and debris before matting and framing artwork with glass. They also removed dirt and dust from the frames before paint. This wasn’t your typical manufacturing environment yet they were still held to the same standards and were made safe by implementing engineered solutions such as our Super Air Nozzle.

If you would like to discuss how we can help increase your operator safety and ensure you meet or exceed OSHA 29 CFR 1910.242(b), please contact an Application Engineer today.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – OSHA Instruction STD 01-13-001 – Retrieved from: https://www.osha.gov/enforcement/directives/std-01-13-001

Fasteners: SAE, Metric, Titanium, Stainless. Yes, We Can Accommodate.

Published on by Brian FarnoLeave a comment

In a previous life I worked in the metal cutting industry on machines that were all imported to the USA. Every machine we brought in had to have the air inlets changed out to match the NPT ports that most of our domestic customers had within their facilities. This simply made sense, why force someone to change an air fitting or something as simple as that to match the rest of their facility. The option we did not offer was to change all the hardware on the machine to match the rest of the SAE sized hardware and limit the number of tools their staff needed. That didn’t make sense. Well, here at EXAIR we like to do things differently.

There are several companies that I deal with here who always prefer their air inlets be different, whether it be a metric BSP thread or a larger NPT thread, maybe a global thread, or even a special fitting like a taper lock fitting. No matter the needs, as long as it will physically fit on the product, chances are we can offer the fitting that will simplify installation. Even past the installation we like to look forward to the complete ownership of our products. Once a machine is located in a facility, what other types of fasteners are used, what is the rest of the machine tooled with. When working on a machine as a maintenance person or adjusting the operation, not having to struggle with determining which Allen wrench or hex size a bolt is and risk damaging the bolt can be extremely helpful.

Most EXAIR products come from stock with standard fractional hardware. We do offer a number of products with a BSPT air inlet and they are often available with the same expediency as our other stock products, same day on orders received by 2 PM ET that are shipping within the U.S. As mentioned above, we can customize a product with the fasteners of your choice, as long as they pass our design criteria. Some of the most common fastener changes I have seen are converting a Super Air Knife to an M6-1.0 threaded bolt rather than the stock 1/4-20 fastener. There are a multitude of other requests that I recall throughout the years. Some of the most intricate are listed and explained below.


Specialty Hardware

From left to right: M6-1.0 stainless steel bolt, a titanium hex-head bolt, a Hastelloy hex-head bolt, brass hex-head bolt, Kolsterized hex-head bolt, special acorn head fastener, Allen key flat-head bolt. Each of these fasteners has been used within a custom configuration to meet a specific need, whether it be simply to match the metric or SAE hardware in the rest of the machine or to meet the demands of the environment they are going into. The bottom row are, integral star washer nut, serrated safety washer, and spring washer. Each of these has, again, been requested by a customer to meet the design and safety standards they have a requirement for. These are just a sampling of the custom hardware we have used over the years to support our customer base and fill their need with product that meets their standards.

If you would like to discuss custom hardware in a stock product or even a full on custom point of use compressed air product, the Application Engineer team here is ready to help. Contact us and we will do our best to understand what your need requires and offer a solution to fit.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Wet-Dry Vacuum Converts Without Tools in 15 Seconds or Less!

Published on by Brian FarnoLeave a comment

In a recent video, I showcased our newest Industrial Housekeeping product, the EasySwitch Wet-Dry Vac. Throughout my years in metalworking as well as homeownership, I have honestly never used a wet-dry vacuum that is this easy to change operating modes from wet to dry or vice versa. So just how easy is it?

EasySwitch Wet-Dry Vac Mode Change Instructions

When writing out instructions on how to do this it takes a total of five steps for either direction. These five steps can easily be completed in less than 15 seconds and best of all, it is tool-free.

When changing over other wet/dry vacuums, whether it is a traditional electric vacuum like you may have at home or another pneumatic industrial vacuum on the market, the switchover process is cumbersome. There are typically fasteners or retainers that are necessary to hold the filters in place, filters can be poor quality and get damaged easily.  Small parts needed to hold filters in place like springs or retainer nuts can easily be lost, hard to manipulate and take additional time changing from liquid to dry modes or vice-versa. With the EasySwitch, the only fastener is a rubber latch that is attached to the filter hatch cover. This means operators can’t lose parts because they are all attached to the EasySwitch Lid. To convert from a dry vacuum to a wet vacuum the steps are simple.

  1. Turn off the compressed air and unlatch the rubber handle. This makes it possible to complete step two.
  2. Lift the filter hatch lid and let it rest on the hinge stop. This is all designed to be robust enough to easily support the weight of the EasySwitch unit as well as the air hose attached to it.
  3. Lift the filter, whether it is the HEPA rated filter or the standard filter, up and out of the lid.
  4. Close the filter hatch lid onto the edge gasket that stays firmly in place.
  5.  Latch the rubber handle/latch back into place and start processing liquid as needed.

That’s it, it takes less than 15 seconds in the video below (see it at 1:15) and I am pretty sure a speedcuber or cup stacker could do it even faster. Don’t believe me, want to test it out for yourself, we honor a 30-day guarantee on stock products. Get the EasySwitch Wet-Dry Vac in your facility and put it through your own rigorous testing. If it doesn’t perform to your liking, let us know and we will arrange for sending it back. Converting the vacuum from dry to wet isn’t the only thing that is fast, we also ship same day on orders for stock products (hint: all EasySwitch vacuums are stock product) received by 3 PM ET that are shipping within the US. (2 PM ET for orders billing and shipping to Canada.)

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF