A manufacturing plant was using extruded aluminum structural framing for making benches. After the aluminum parts were cut, they had coolant and chips inside the tube. They tried to run a rag through the center to remove the material, but it wasn’t able to get into all the crevices and before long the rag was saturated. Also, they noticed that the chips would scratch the internal surfaces. For this company, quality was very important to represent their brand. So, they were needing a non-contact way to clean the inside of these parts after sawing. They contacted EXAIR as we share the same business facets of first-class customer service and great quality.
At EXAIR, we design and manufacture nozzles for just this type of operation; the Back Blow Air Nozzles. We offer three different sizes to fit inside a wide variety of diameters from ¼” (6.3mm) to 16” (406mm). They are designed to clean tubing, pipes, hoses, channels, and extruded “odd” shapes. The 360o rear airflow pattern can “wipe” without touching the internal surface to remove coolant and chips. For the application above, I recommended the model 1006SS Back Blow Air Nozzle to fit inside the 1 ½” (38mm) opening. The range for this Back Blow Air Nozzle is from 7/8” (22mm) to 4” (102mm) diameters. This 316SS robust nozzle would last a long time without having to change or replace cloth rags.
After installing the model 1006SS onto an extension pipe, the cleaning operation became very easy and efficient. After each cut, they would run the Back Blow Nozzle through the center with only one pass to clean. The non-contact wiping removed the coolant and chips without marring the internal surface. In addition, they were able to speed up their operation by 20%. Cleaner tubes, less time, cost savings; they were happy that they contacted EXAIR for our expertise.
If you need to clean the inside of tubes, hoses, pipes, etc., EXAIR has the perfect nozzle for you, the Back Blow Air Nozzles. EXAIR can also offer these nozzles on our VariBlast, Soft Grip, and Heavy Duty Air Guns for manual operations. They come with Chip Shields and extensions that can reach as far as 72” (1829mm). Or like the customer above, automate the system to get a great non-contact cleaning. If you require any more details, you can contact an Application Engineer at EXAIR. We will be happy to help you.
At EXAIR, we have a statement, “Safety is everyone’s responsibility”. And we also manufacture safe compressed air products. In the United States, we have an organization called Occupational Safety and Health Administration, OSHA, that enforces directives for safe and healthy working environments. They do training, outreach programs, and educational assistance for manufacturing plants. They will also enforce these directives with heavy fines for violations. The two most common violations with compressed air are air guns and blow-off devices are described in 29CFR 1910.242(b) for dead-end pressure/chip shielding and 29CFR 1910.65(a) for maximum allowable noise exposure.
Here is an example of a nozzle that is dangerous. As you can see, there is only one opening where the air can come out from the nozzle. Other types of nozzles that would fall into this same group would include copper tube, extensions, and open pipes.
They are dangerous as the compressed air cannot escape if it is blocked with your body or skin. If operated above 30 PSIG (2 bar), these nozzles could create an air embolism within the body which can cause bodily harm or death. This is a hazard which can be avoided by using EXAIR Super Air Nozzles and Safety Air Guns. The nozzles are designed with fins which allows the air to escape and not be blocked by your skin. So, you can use the EXAIR Super Air Nozzles safely even above 30 PSIG (2 bar).
To counteract the dead-end pressure violation, some nozzle manufacturers create a hole through the side of the nozzle (Reference photo above). This will allow for the compressed air to escape, but, now the issue is noise level. With an “open” hole in the nozzle, the compressed air is very turbulent and very loud. The National Institute for Occupational Safety and Health, NIOSH, states that 70% to 80% of all hearing loss within a manufacturing plant is caused by compressed air. OSHA created a chart to show the maximum allowable noise exposure. This chart shows the time and noise limits before requiring hearing protection. The EXAIR Super Air Nozzles, Super Air Knives, Super Air Amplifiers are designed to have laminar flow which is very quiet. As an example, the model 1210 Safety Air Gun has a sound level of only 74 dBA; well under the noise exposure limit for 8 hours.
NIOSH created an overview of how to handle hazards in the workplace. They call it the Hierarchy of Controls to best protect workers from dangers. The most effective way is by eliminating the hazard or substituting the hazard. The least effective way is with Personal Protective Equipment, or PPE. For unsafe compressed air nozzles and guns, the proper way to reduce this hazard is to substitute it with an engineered solution.
One of the last things that companies think about when purchasing compressed air products is safety. Loud noises and dead-end pressure can be missed or forgotten. To stop any future fines or additional personal protective equipment (PPE), it will be much cheaper to purchase an EXAIR product. And with the Hazard Hierarchy of Controls, the first method is to remove any hazards. The last method for control is to use PPE. In the middle of the hierarchy is for an engineered solution. EXAIR products are that engineered solution. If you would like to improve the safety in your facility with your current blow-off devices, an Application Engineer can help you.
A common item that can be found in a majority of machine shops is the blue or gray knuckle-jointed hose used to dispense coolant on lathes and CNC machines. EXAIR also uses this same hose with our Cold Guns and Adjustable Spot Coolers for applications that cannot or do not wish to use liquid coolant as a means of keeping the heat down on their tooling. Since the cold air discharges at atmospheric pressure, this is an acceptable application.
Another application is using this style of hose as a compressed air blowoff. This is NOT a proper use of the hose and is not only a considerable waste of compressed air but can also pose a safety hazard. Using this method for compressed air blowoff is not compliant with OSHA 1910.242(b).
I was recently contacted by a customer in Indonesia that was using an array of (6) of these knuckle-jointed hoses with a ¼” round nozzle attachment for a blowoff operation. The customer had a series of rubber pads used in the construction of a toy castle. The pads were brought along by an overhead conveyor and a design was printed on the head of the pad.
The nozzles were used to dry the ink before the pad made it to the next part of the process. This was a new product line and the processes involved were being evaluated for potential places to save on compressed air rather than adding overall capacity to their system. After using a variety of EXAIR products for other blowoff applications, they came back for another engineered solution.
After testing both a 1009-9280 (Adjustable Air Nozzle w/ 30” Stay Set Hose) and an HP1126-9280 (1” High Power Flat Nozzle w/ 30” Stay Set Hose), the customer determined that the airflow pattern from the 1” Flat Nozzle was more conducive to drying the rubber pad and purchased the remaining units to replace their original method. The compressed air savings was noticed immediately!!
For the old operation, they had to regulate the pressure down on the hose to 25 psig so that the hose wouldn’t break apart. (1) This hose , with a ¼” round nozzle, will consume 52 scfm at 25 psig of supply pressure. With (6) of these they were consuming a whopping 312 scfm!! Since the HP1126 is compliant with OSHA directive 1910.242(b) and will not break apart at higher pressures, they were able to operate at 80 psig while only consuming 17.5 scfm. They saved more than enough air for their new process and are evaluating whether or not they can turn off one of their smaller 25 HP compressors.
The new setup with the EXAIR engineered solution was able to save them 207 scfm of compressed air. Assuming a cost of $.25/1000 scfm and a 40 hr work week, this translates to an overall savings of $6,458.40 per year off of their utility bill.
207 scfm x 60 minutes x 8 hrs/day x 5 shifts/week x 52 weeks/year =25,833,600 scf
25,833,600 scf x ($.25/1000 scf) = $6,458.40
If you’re using an inefficient compressed air blowoff in your facility, give us a call. An Application Engineer will be happy to evaluate your process and determine the safest and most efficient solution. With same day shipment for stock items on orders placed by 2:00 pm ET, we can get a solution out to you fast. And you can be saving money upon installation!
I had a customer wanting to reject a container off a conveyor belt. The container held yogurt, and when an optic detected a reject, they wanted to operate a solenoid to have a nozzle blow the container into a reject bin. They had a range that went from 4 oz. (113 grams) for the small containers to 27 oz (766 grams) for the large. He wanted me to suggest one nozzle for all sizes, as they would automatically regulate the pressure for the full range of products. In looking at the largest size, this container will need the most force to blow off the conveyor. The two factors that affects the force in this type of application is weight and friction. When it comes to friction, it is generally an unknown for customers. So, I was able to help with a couple of things to determine the friction force.
Friction is a dimensionless number that represents the resistance created between two surfaces. We have two types; static friction, ms, and kinetic friction, mk. Static friction is the maximum amount of resistance before the object begins to move or slide. Kinetic friction is the amount of resistance that is created when the object is moving or sliding. So, Static friction is always greater than kinetic friction, ms > mk. For this application, we will use an air nozzle to “shoot” horizontally to hit the rejected product.
Let’s take look at our customer’s application. We have a system to reject a non-conforming part with air. The conveyor has a urethane belt. The container is plastic. For the largest container, they have a weight of 27 oz. (766 grams). Being that the conveyor belt is only 12” (30.5 cm) wide, we can determine that if we get the part moving, it will continue off the belt and into the reject bin. The equation for the maximum amount of force required to move a container is below as Equation 1.
Fs = ms * W
Fs – Static Force in ounces (grams)
ms – Static Friction
W – Weight in ounces (grams)
One way to determine the amount of force is to use a scale similar to a fish scale. The scale should have a maximum indicator to help capture the maximum amount of force. You will have to place the object on the same belt material because different types of materials will create different static forces. Keep the scale perpendicular to the object, and slowly pull on the scale. Once the part begins to move, record the scale reading. For the exercise above, it showed 9.6 oz. (271 grams) of force to move the 27 oz. (766 gram) object.
Another way would be to calculate the static friction, ms. Static friction can be found by the angle at which an object starts to move. By placing the container on a section of supported urethane conveyor belt, you can lift one end until the object starts to slide. The height of the lift can be measured as an angle. As an example, we take 3 feet (0.9 meter) of supported urethane conveyor belt, and we lifted one end to a height of 1 foot (0.3 meters) before the 27 oz (766 gram) container moved. To determine static friction, it is the tangent of that angle that you lifted. With some right triangle trigonometry equations, we get an angle of 19.5o. Thus, ms = tanq or ms = tan(19.5o) = 0.354. If we plug this into Equation 1, we get the following:
Imperial UnitsSI Units
Fs = ms * W Fs = ms * W
= 0.354 * 27 oz. = 0.354 * 766 grams
= 9.6 oz. of force = 271 grams of force
Now that we have the static force, we want to be slightly higher than that. In looking at the force requirements that are published in the EXAIR catalog, it shows that the model 1126 1” Super Flat Air Nozzle has a 9.8 oz. (278 grams) of force at 80 PSIG (5.5 Bar). This force is measured at a 12” (30.5 cm) distance with a patented .015” (0.38mm) shim. So, this nozzle will be able to slide the largest container into the reject bin.
To expand on the benefits in using the EXAIR Flat Super Air Nozzles, the force can be changed easily with a regulator or with a Shim Set. This is a unique feature as most competitive flat nozzles do not allow you to do this. The patented shims control the force rating in a wide range with lower air consumption and lower noise levels; making them safe and efficient. So, if this manufacturer decided to produce other sizes in the future, then they could change the shim to target even larger containers. The flexibility of using the EXAIR Flat Super Air Nozzles allow you to increase or decrease the force by just removing two screws and changing the thickness of the shim inside. EXAIR does offer a pack of shims with different thicknesses which are called a Shim Set.
With air pressure or shim manipulation, the customer could use the same nozzle for the yogurt containers. If you have any applications that need products to be rejected quickly, an Application Engineers at EXAIR will be happy to help you with a solution.