In industrial settings, having a single air nozzle or other blowoff product is often not the scenario that is seen. Many applications require multiple points of blowoff, even if not in the same direction or for the same position within the machine. In the scenario where multiple nozzles are used, sound levels can get tricky to calculate and is often thought of as a mystery. If you follow our blog then you may have seen this excellent blog that shows all the math behind calculating the total decibels when multiple sources of noise will be present. The video below gives a demonstration of utilizing two of the EXAIR model 1100 – 1/4″ FNPT Super Air Nozzle.
In the video you see a model 1100 being operated and producing a sound level of 74 dBA from 3′ away from the nozzle point. When the second nozzle is turned on (also producing 74 dBA individually), the pressure is adjusted back up to the same input pressure and the sound level meter registers 78 dBA from 3′ away. Following the math laid out in the “excellent blog” link above, the sound level calculated comes out to be the same 78 dBA that is shown in the video using EXAIR’s Digital Sound Level Meter.
If you would like help determining the sound levels within your facility, check out the EXAIR Digital Sound Level Meter as well as reach out to an Application Engineer.
Over the years, EXAIR has come across a variety of different types of blow-off devices. We have seen copper tubes, pipes with a crushed end, fittings with holes drilled into them, and modular flex lines. For compressed air use, these are very dangerous and very inefficient. In many instances, companies will go through a mixed bag of items to make a blow-off device for their application. It is inexpensive to do. But what they do not realized is that these items are very unsafe and will waste your compressed air, costing you much money in the long run.
When EXAIR started to manufacture compressed air products in 1983, we created a culture in making high quality products that are safe, effective, and efficient. Since we stand by our products, we created a program called the Efficiency Lab. We test blow-off devices against EXAIR products in noise levels, flow usage, and force measurements. With calibrated test equipment, we compare the data in a detailed report for the customer to review. If we are less effective, we will state that in the report, but this is very rare. With this quantified information, we can then determine the total amount of air savings and safety improvements that EXAIR products can offer.
With our Efficiency Lab, it is quite simple to do. For starters, you can go to our Product Efficiency Survey on our website to give the conditions for testing. If you wish for a side by side analysis, you can place your pneumatic device in a box and send it to EXAIR. We will run the tests at the specified conditions or in a range of settings. We will then return your pneumatic device back to you with a report of the comparison. This report can be used to show managers, executives, HSE, etc. on the improvements that EXAIR can provide in cost savings and safety.
In a recent Efficiency Lab, a customer sent us a water jet nozzle that he was using to blow off product passing on a conveyor (reference photo above). The customer supplied us with the required information to test. They had three water jet nozzles on a manifold that had ¼” NPT male connections. The air pressure was set at 75 PSIG (5.2 bar), and the air pattern was round. Their annual usage for this blow-off device was 7000 hours continuous, and their electric rate for their facility was $0.10/KWh. The reason that they sent their nozzle to EXAIR was because the operation was very loud, and they believed that they were wasting compressed air. They asked me for a recommendation and what the payback period might be with my selection.
I recommended the model 1101 Super Air Nozzle as our standard round pattern with a ¼” NPT male connection. With our engineered design, the Super Air Nozzle can entrain the “free” ambient air into the air stream to generate a hard-hitting force; using less compressed air. Also, with this suggestion, they will not have to redesign their blow-off station; just remove the water jet nozzles and replace them with the Super Air Nozzles. We tested the water jet nozzle, and we found that it used 17.5 SCFM (496 SLPM) at 75 PSIG (5.2 bar). The noise level was measured at 91.2 dBA for a single nozzle. As a comparison, the model 1101 Super Air Nozzle will only use 13.3 SCFM (376 SLPM) of compressed air at 75 PSIG (5.2 bar); and, the noise level was reduced to 73 dBA for each nozzle.
The first thing that is important to me is safety. High noise levels will cause hearing damage. OSHA generated a standard 29CFR-1910.95a with a chart for Maximum Allowable Noise Exposure. To calculate the noise level for three nozzles, I will reference a previous blog that I wrote: “Measuring and Adding Sounds”. With three water jet nozzles, the total sound is 96 dBA. From the OSHA table above, the usage without hearing protection is less than 4 hours a day. With the Super Air Nozzles, the noise level will be 78 dBA for all three nozzles; well below the requirement for 8 hours of exposure. It is difficult to put a monetary value on safety, but using PPE should never be the first step as a solution.
For the annual savings and the payback period, I will only look at the electrical cost. (Since the Super Air Nozzle is using less compressed air, the maintenance and wear on your air compressor is reduced as well).
The air savings is calculated from the comparison; 17.5 SCFM – 13.3 SCFM = 4.2 SCFM per nozzle. With three nozzles, the total compressed air savings will be 12.6 SCFM for the blow-off station. An air compressor can produce 5.36 SCFM/KW of electricity at a cost of $0.10/KWh. For an annual savings, we have the figures from the information above; 7000 hours/year * 12.6 SCFM * $0.10/KWh * 1KW/5.36 SCFM = $1,645.52/year. For the payback period, the model 1101 Super Air Nozzle has a catalog price of $44.00 each, or $132.00 for three. The customer above did not disclose the cost of the water jet nozzles, but even at a zero value, the payback period will be just under 1 month. Wow!
Not all blow off devices are the same. With the customer above, they were able to reduce their noise levels and compressed air consumption. If your company decides to select an unconventional way to blow off parts without contacting EXAIR, there can be many hidden pitfalls; especially with safety. Besides, if you can save your company thousands of dollars per year as well, why go with a non-standard nozzle? If you have a blow off application and would like to compare it against an EXAIR product, you can discuss the details with an Application Engineer. What do you have to lose?
As compressed air technology advanced through the 20th Century, its uses multiplied. Pneumatic cylinders became common for rolling and forming presses. The convenience and portability of powerful pneumatic hand held tools spread in assembly and manufacturing facilities. Along the way, operators also found that an open-ended compressed air line could be used for quick and easy blow off in a number of applications. There were, however, some pretty risky safety issues associated with this.
In December of 1970, the Occupational Safety & Health Act became the law of the land, and in 1971, the Occupational Safety & Health Administration (OSHA) was created. Among the many hazards in workplaces they targeted was compressed air use for cleaning. The primary concerns were:
An open ended blow off could inadvertently be dead ended onto a person’s body, and if the pressure were high enough, it could break the skin and cause a deadly condition called an air embolism. So they limited the outlet pressure to 30psi.
Blowing something off with air can (and usually does) result in airborne particulate traveling at a high velocity that can imbed in your skin or in your eye. So they mandated the use of proper chip guarding, protective clothing, and eye protection.
This is where the history of the safety air gun begins. Through the 1970’s & 1980’s, engineers rolled out product after product conforming with these new safety standards, sometimes looking for economy, sometimes efficiency…and occasionally, both.
It’s not hard to make a blow off nozzle that complies with OSHA’s dead end pressure requirement; you just need to provide a path for the air to escape in case the nozzle end is blocked. Cross drilled nozzles (shown at right) are simple, cheap, and OSHA compliant, but they’re also loud & inefficient.
EXAIR’s Super Air Nozzles not only protect against injury from dead ended high pressure air, their engineered design also makes them quiet, and efficient. They are commonly installed on the Soft Grip Safety Air Gun. Along with our Chip Shields(shown at right) and your personal protective equipment, you get OSHA compliance, AND lower air consumption & noise levels.
With the Soft Grip Safety Air Gun, you also get a diverse range of options to suit the specific needs of numerous applications:
Cleaning out the inside diameters of tube, pipe, channel, blind holes, etc., has never been easier than the Soft Grip Back Blow Safety Air Guns. You can get it with the 1004SS (1/4″ to 1″ diameters; 6″ to 36″ extensions) or the 1006SS (7/8″ to 4″ diameters; 6″ to 72″ extensions) Back Blow Nozzles.
If you’re looking for a hand held blow off device, your choices are many. If you’re looking for a quiet, efficient, safe, and versatile one, your choice is easy: the EXAIR Soft Grip Safety Air Gun. Call me and we’ll figure out which one you need.
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The gun has a number of benefits starting with the metal 3/8″ NPT inlet which permits air flows high enough to operate our model 1106 – 1/2″ Super Air Nozzle. With the 1106 Super Air Nozzle on the gun it will provide 3.3 lbs of force to provide ample cleaning, clearing, or cooling air for the tough industrial jobs.
Secondly, the gun offers an over molded grip that is ergonomic and rugged to handle the industrial environments that maintains its grip even when doused in coolants.
Third, the gun offers a cast 4 finger blade style trigger that permits ergonomic easy trigger pull that can be easily used throughout a work shift. In the event the trigger becomes damaged it can also be easily replaced with stock parts direct from EXAIR.
Fourth, we easily offer any of the Heavy Duty Safety Air Gun combinations with extensions up to 72″ in length and with or without the Chip Shield option.
Lastly, as mentioned in first point, the gun and extensions can be combined with any of the EXAIR Super Air Nozzles up to 1/2″ NPT inlet. Whether you need a small precision puff of air from the Atto Super Air Nozzle, the forcefull blast of the 1106 1/2″ Large Super Air Nozzle, or anywhere in between, there is an engineered nozzle for it and we can couple them with the Heavy Duty Safety Air Gun.
To find out what kind of Safety Air Gun can fill the needs of your application, feel free to contact us. If you are using an existing non-engineered gun and would like to explore the safe, quiet world of engineered air nozzles coupled with safety air guns, then feel free to reach out to us and inquire about our FREE Efficiency Lab Service.
Noise-induced hearing loss, or NIHL, is one of the most common occupational diseases. This doesn’t occur overnight, but the effects are noticed gradually over many years of unprotected exposure to high sound levels. This is 100% preventable! Through proper engineering controls and personal protective equipment (PPE), NIHL can be prevented. It is irreversible, so once the damage is done there’s no going back. OSHA standard 19 CFR 1910.95(a) states that protection against the effects of noise exposure shall be provided when the sound levels and exposure time exceed those shown in the table below.
Intensity of the sound pressure level is expressed in decibels (dB). The scale is logarithmic, a 3 dB reduction cuts the sound level in half. A 10 dB reduction decreases it by a factor of 10, and a 20 dB reduction decreases the sound level by a factor of 100. To calculate the dB level, we use the following formula:
L – Sound Pressure Level, dB
P – Sound Pressure, Pa
Pref – reference sound pressure, 0.00002 Pa
For example, normal conversation has a Sound Pressure of .01Pa. To calculate the dB level:
dB = 20 log10 (.01Pa/.00002Pa)
= 54 dB
When designing a new blowoff process, it’s important to consider the sound levels produced before implementation. EXAIR publishes the sound level for all of our products for this very reason. If you’re implementing multiple nozzles, you’ll need to add the sound levels together. To do so, we use the following formula:
L1, L2… represent the sound pressure level in dB for each source
A customer was using ¼” open ended copper tubes for a blowoff application removing trim after a stamping operation. They had a total of (4) tubes operating at 80 PSIG. Not only were they VERY inefficient, but the sound level produced at this pressure was 94 dBA. To calculate the sound level of all (4) together we use the above formula:
L = 10 x log10(109.4+ 109.4 + 109.4 + 109.4)
L = 100 dB
At this sound level, permanent hearing loss begins to occur in just two hours of unprotected exposure. We recommended replacing the loud and inefficient copper pipe with our 1” Flat Super Air Nozzle, Model 1126. At 80 PSIG, the 1126 produces a sound level of just 75 dBA.
L = 10 x log10 (107.5 + 107.5 + 107.5 + 107.5)
L = 81 dB
At almost a 20 dB reduction, that’s nearly 100x quieter! Don’t rely on just PPE to keep your operators safe from NIHL. Replacing loud inefficient blowoff methods with EXAIR’s Intelligent Compressed Air Products will take it one step further in ensuring your creating a safe working environment for your employees.
But we didn’t need awards to tell us how great they are. EXAIR Corporation has 35 years of continuously improving experience in the design, engineering, and manufacture of quiet, safe, and efficient compressed air products for industry. The VariBlast Compact Safety Air Guns are just another innovation that’s come to fruition, courtesy of the knowledge, experience, and dedication to quality from our R&D Engineering & Production departments.
But you don’t have to take OUR word for it: a satisfied customer base has proven the VariBlast Compact Safety Air Gun‘s success: We offer a 30 Day Unconditional Guarantee on any catalog product. That means you can put it through its paces for up to a month…if it’s not going to work out, for any reason, we’ll arrange return for full credit. Of the dozens of VariBlast Safety Air Guns we’ve sold every month for the last two years or so, we have not had one returned. Not. One. To which I say: no wonder…check it out:
If you’re looking for an economical, efficient, quiet, variable flow, handheld blow off solution, look no further than the VariBlast Compact Safety Air Gun…just another award winning Intelligent Compressed Air Product, brought to you by EXAIR. To the readers of Industrial Safety & Hygiene Magazine…thanks for noticing!
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In today’s market, the cost of consumable products are on the rise; especially with paints, oils, and yes, even the cost of water. You can help ease some of that cost by being more effective in spraying with less liquid. The EXAIR Atomizing Nozzles can accomplish these objectives. By using compressed air to shear the liquid, small micron-sized droplets are produced. As a reference, reducing the area of a particle by one-half will multiply the number of droplets by eight. With smaller diameter particles, it will increase the surface area and the coverage; thus, requiring less liquid in your application.
In addition, with a variety of spray patterns, you can accurately target the liquid without having excess spillage around the product. EXAIR manufactures three families of Atomizing Nozzles; Internal Mix, External Mix, and Siphon Fed. In this blog, I will be discussing the Internal Mix Atomizing Nozzles.
The Internal Mix Atomizing Nozzles are designed, like the name suggests, to atomize the liquid inside the nozzle. This means that the liquid and air streams will come together just before leaving the Atomizing Nozzle. For this type of Atomizing Nozzle, the air and liquid supply are pressurized and independently controlled.
The Internal Mix Atomizing Nozzle can spray fluids with a viscosity below 300 CPS (similar to SAE40 oil). EXAIR manufactures these nozzles with stainless-steel construction; making them compatible with many different kinds of liquids. And they are used in many applications like washing, coating, cooling, quenching, and dust control.
EXAIR carries three different body sizes in 1/8” NPT, ¼” NPT, and ½” NPT inlet ports; so, you can create a light mist or a monsoon. Each body size has different air caps and liquid caps to control the largest liquid flow rates. This will allow you to have finer adjustments of your liquid spraying. These caps are easily interchangeable to change the spray patterns, spray amounts, and to reduce downtime if cleaning is needed.
Other features for the Atomizing Nozzles are the mechanisms to precisely regulate the amount of liquid being sprayed. The liquid adjusting stem can control the liquid flow into the Atomizing Nozzle. Along with inlet air pressure and liquid pressure, you can “dial in” the exact amount of fluid to end any waste or excess. They have a compact design to mount inside tight areas, and we carry mounting brackets for easy attachment and positioning. Versatility is very important in saving, applying, and spraying costly fluids, and the Internal Mix Atomizing Nozzles have it.
To help reduce excess fluid even more, EXAIR has a No Drip option. This patented option is used to keep the expensive liquid from dripping out of the Atomizing Nozzles during off cycles. A valve inside the body will create a seal on the liquid side when you turn off the compressed air. For delicate and sensitive applications, the unwanted drips will not occur with the No Drip option to ruin the finish of your product. This option also enhances the Internal Mix Atomizing Nozzle for intermittent spraying processes. It will keep the liquid inside the body of the nozzle; so, when you apply air pressure, the Atomizing Nozzle will give an instant spray.
Unlike some manufacturers, there is no need to run a separate compressed air line or have a liquid solenoid valve to stop the dripping. The Internal Mix Atomizing Nozzles with the No Drip options can give you the best performance in efficiency, effectiveness, and flexibility without any drips.
If you need to maximize the liquid dispersion and reduce consumption, the EXAIR Atomizing Nozzles are the products to use. The Internal Mix Atomizing Nozzles can shear the drops into micron-sized particles, saving expensive consumable oils and liquids. If you have a spraying application, an Application Engineer at EXAIR can help you to decide the correct model.