Recently, I worked with a production engineer at a Tier 1 supplier for the auto industry. An upcoming project was in the works to install a new line to produce headlight lenses. As a part of the process, there was to be a “De-static / Blow-off” station, where a shuttle system would bring a pair of the parts to a station where they would be blown off and any static removed prior to being transferred to a painting fixture and sent off for painting. For best results, the lenses were to be dust and lint free and have no static charge, ensuring a perfect paint result.
The customer was limited in compressed air supply volume in the area of the plant where this process was to occur. 50 SCFM of 80 PSIG was the expected air availability at peak use times, which posed a problem – the Super Ion Air Knives would need up to 105 SCFM if operated at 80 PSIG. A further review of the design parameters for the process revealed that the system needed to blow air for only 4 seconds and would be off for 25 seconds to meet the target throughput.
This scenario lends itself perfectly to the use of a Receiver Tank. Running all of the design numbers into the calculations, showed that the 60 Gallon Receiver Tank we offer, would allow for a 20 second run-time, and require 13.1 seconds to refill. These figures were well within the requires times, and would allow for the system to work as needed, without having to do anything to the compressed air supply system.
The moral of the story is – if you have a process that is intermittent, and the times for and between blow-off, drying, or cooling allows, a Receiver Tank can be used to allow you to get the most of your available compressed air system.
Note – Lee Evans wrote an easy to follow blog that details the principle and calculations of Receiver Tanks, and it is worth your time to read here.
If you would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
So, you’ve selected a quiet, efficient, and safe EXAIR Super Air Nozzle for your blow off application – good call! – and now you’re thinking about how to install it. Sometimes, it’s as simple as replacing whatever you’re using right now:
Or maybe you’re using an open end blow off…in which case, you’re just an adapter away:
Perhaps, though, it’s a new installation, or the existing supply lines aren’t suitable for one reason or another. In those cases, we’ve still got you covered…consider the EXAIR Stay Set Hose:
Available in a variety of lengths from 6″ to 36″, they’re positionable, and re-positionable with a simple bending action. They won’t kink or easily fatigue like copper tubing. The supply end is 1/4 MNPT, and you have your choice of 1/4 MNPT or 1/8 FNPT on the other end, depending on which Super Air Nozzle, Air Jet you need to use it with.
We also offer Blow Off Systems, which are a combination of a specific Air Nozzle (or Air Jet,) fitted to a Stay Set Hose:
For added convenience and ease of installation, these products can also come with a Magnetic Base:
From the beginning in 1983, EXAIR’s focus has been on being easy to do business with, and that goes from our friendly customer service to our expert technical support to our 99.9% on-time shipments (22 years and running) to designing our engineered products and value-added accessories with efficiency, safety, and ease of installation in mind. If you want to find out more, give me a call.
OSHA Standard 29 CFR 1910.95(a), relating to permissible noise exposure levels, states that when employees are subjected to sounds in excess of 90 dBA, some type of control should be used to reduce the sound level. In an industrial setting, it’s very common to find the exhausting air from air operated devices such as actuators, diaphragm pumps or cylinders for example, to produce sound levels well above the allowable limits set forth in the Standard. EXAIR offers a variety of different Silencing Mufflers that help to reduce this noise level, while also increasing operator safety.
EXAIR’s Reclassifying Mufflers offer noise reduction up to 35 dB and are available in sizes ranging from 1/8″ to 1″ NPT. These types of mufflers are often considered”dual-purpose” as they not only reduce the noise level but also remove oil from the exhaust airflow by incorporating a removable filter element. The exhausting oil mist is reduced from 50 PPM (parts per million) to only 0.015 PPM, when the device is operated at 100 PSIG. In addition, there is a bowl on the bottom to capture any residual oil and a 1/4″ tube adaptor to allow for easy draining.
Sintered Bronze Mufflers are a relatively low cost option, commonly used with air cylinders as they can be installed quick and easy. We offer 1o different sizes, ranging from #10-32 for small installations, up to 1-1/2″ NPT for larger scale applications. The noise reduction depends on the size of the muffler and back pressure, which can occur from dirt or particulate clogging the muffler, restricting the exhausting airflow from passing through the porous sintered bronze.
Our Straight Through Mufflers are made of corrosion resistant aluminum and are lined with a sound absorbing foam, capable of reducing noise levels up to 20 dB. We offer 3 different sizes, 1/4″, 3/8″ and 3/4″ NPT, with a male thread on one end and female thread on the other. We incorporate this muffler design into our Cold Guns and Adjustable Spot Coolers and they are commonly used with our Vortex Tubes, Cabinet Cooler® Systems and E-Vac® Vacuum Generators as well.
Lastly, the Heavy Duty Mufflers feature an internal, 50 mesh stainless steel screen, to protect against contaminants in the airflow, and a corrosion resistant aluminum outer shell. In most cases, the sound reduction can be as high as 14 dB and we offer 2 different sizes, 1/4″ and 3/8″ FNPT. These types of mufflers are regularly used on the hot air exhaust of our Vortex Tubes.
For help with product selection or to discuss a particular process, please contact one of our application engineers at 800-903-9247.
A little while back, I worked with a large eyeglass manufacturer on a sunglass lens cooling application. In their setup, they were dry cutting film-coated lenses with a router and after the lenses are cut, they are passed through several different rinse cycles and inspected for scratches or other damage. They were seeing a high number of reject parts and determined that the heat being generated by the tooling, was causing the irregularities. In an effort to alleviate the condition, they used a section of open flexible tubing to blow compressed air at the bit, which helped a little, but they were still concerned with the amount of scrap material.
I recommended they use our Model # 3825 Adjustable Spot Cooler System in the process. The Adjustable Spot Cooler incorporates a Vortex Tube to provide a temperature drop from the incoming supply air temperature. Using the temperature control valve, the exhausting air temperature and flow can be adjusted to fit the application. The system includes a flexible hose to focus the cold air to the desired area until re-positioned. The system also features a magnetic base that allows for easy mounting. By incorporating the filter separator included in the system, they can remove any moisture and/or contaminants in the air supply, relieving any concern with contamination or damage to the part.
If you have a cooling application you’d like to discuss or for help selecting the best product to fit your need, give me a call at 800-903-9247.
Compressed air regulators are a pressure reducing valve that are used to maintain a proper downstream pressure for pneumatic systems. There are a variety of styles but the concept is very similar; “maintain a downstream pressure regardless of the variations in flow”. Regulators are very important in protecting downstream pneumatic systems as well as a useful tool in saving compressed air in blow-off applications.
The basic design of a regulator includes a diaphragm, a stem, a poppet valve, an orifice, compression springs and an adjusting screw. I will break down the function of each item as follows:
Diaphragm – it separates the internal air pressure from the ambient pressure. They are typically made of a rubber material so that it can stretch and deflect. They come in two different styles, relieving and non-relieving. Relieving style has a small hole in the diaphragm to allow the downstream pressure to escape to atmosphere when you need to decrease the output pressure. The non-relieving style does not allow this, and they are mainly used for gases that are expensive or dangerous.
Stem – It connects the poppet valve to the diaphragm. This is the “linkage” to move the poppet valve to allow compressed air to pass. As the diaphragm flexes up and down, the stem will close and open the poppet valve.
Poppet valve – it is used to block the orifice inside the regulator. It has a sealing surface to stop the flowing of compressed air during zero-flow conditions. The poppet valve is assisted by a spring to help “squeeze” the seal against the orifice face.
Orifice – it is an opening that determines the maximum amount of air flow that can be supplied by the regulator. The bigger the orifice, the more air that can pass and be supplied to downstream equipment.
Compression springs – they create the forces to balance between zero pressure to maximum downstream pressure. One spring is below the poppet valve to keep it closed and sealed. The other spring sits on top of the diaphragm and is called the adjusting spring. This spring is much larger than the poppet valve spring, and it is the main component to determine the downstream pressure ranges. The higher the spring force, the higher the downstream pressure.
Adjusting screw – it is the mechanism that “squeezes” the adjusting spring. To increase downstream pressure, the adjusting screw decreases the overall length of the adjusting spring. The compression force increases, allowing for the poppet valve to stay open for a higher pressure. It works in the opposite direction to decrease the downstream pressure.
With the above items working together, the regulator is designed to keep the downstream pressure at a constant rate. This constant rate is maintained during zero flow to max flow demands. But, it does have some inefficiencies. One of those issues is called “droop”. Droop is the amount of loss in downstream pressure when air starts flowing through a regulator. At steady state (the downstream system is not requiring any air flow), the regulator will produce the adjusted pressure (If you have a gage on the regulator, it will show you the downstream pressure). Once the regulator starts flowing, the downstream pressure will fall. The amount that it falls is dependent on the size of the orifice inside the regulator and the stem diameter. Charts are created to show the amount of droop at different set pressures and flow ranges (reference chart below). This is very important in sizing the correct regulator. If the regulator is too small, it will affect the performance of the pneumatic system.
The basic ideology on how a regulator works can be explained by the forces created by the springs and the downstream air pressures. The downstream air pressure is acting against the surface area of the diaphragm creating a force. (Force is pressure times area). The adjusting spring force is working against the diaphragm and the spring force under the poppet valve. A simple balanced force equation can be written as:
Fa ≡ Fp + (P2 * SA)
Fa – Adjusting Spring Force
Fp – Poppet Valve Spring Force
P2 – Downstream pressure
SA – Surface Area of diaphragm
If we look at the forces as a vector, the left side of the Equation 1 will indicate a positive force vector. This indicates that the poppet valve is open and compressed air is allowed to pass through the regulator. The right side of Equation 1 will show a negative vector. With a negative force vector, the poppet valve is closed, and the compressed air is unable to pass through the regulator (zero flow).
Let’s start at an initial condition where the force of the adjusting spring is at zero (the adjusting screw is not compressing the spring), the downstream pressure will be zero. Then the equation above will show a value of only Fp. This is a negative force vector and the poppet valve is closed. To increase the downstream pressure, the adjusting screw is turned to compress the adjusting spring. The additional spring force pushes down on the diaphragm. The diaphragm will deflect to push the stem and open the poppet valve. This will allow the compressed air to flow through the regulator. The equation will show a positive force vector: Fa > Fp + (P2 * SA). As the pressure downstream builds, the force under the diaphragm will build, counteracting the force of the adjusting spring. The diaphragm will start to close the poppet valve. When a pneumatic system calls for compressed air, the downstream pressure will begin to drop. The adjusting spring force will become dominant, and it will push the diaphragm again into a positive force vector. The poppet valve will open, allowing the air to flow to the pneumatic device. If we want to decrease the downstream air pressure, the adjusting screw is turned to reduce the adjusting spring force. This now becomes a negative force vector; Fa < Fp + (P2 * SA). The diaphragm will deflect in the opposite direction. This is important for relieving style diaphragms. This deflection will open a small hole in the diaphragm to allow the downstream air pressure to escape until it reaches an equal force vector, Fa = Fp + (P2 * SA). As the pneumatic system operates, the components of the regulator work together to open and close the poppet valve to supply pressurized air downstream.
Compressed air is expensive to make; and for a system that is unregulated, the inefficiencies are much greater, wasting money in your company. For blow-off applications, you can over-use the amount of compressed air required to “do the job”. EXAIR offers a line of regulators to control the amount of compressed air to our products. EXAIR is a leader in manufacturing very efficient products for compressed air use, but in conjunction with a regulator, you will be able to save even more money. Also, to make it easy for you to purchase, EXAIR offer kits with our products which will include a regulator. The regulators are already properly sized to provide the correct amount of compressed air with very little droop. If you need help in finding the correct kit for your blow-off application, an Application Engineer at EXAIR will be able to help you.
Compressed air filters help to keep the air clean and condensate free to protect equipment from dust, dirt, pipe scale, oil and water. Even though the compressed air system will typically have a main dryer, additional treatment is often necessary. For this discussion, we will focus on the oil removal process and filter type.
After the compressed air has passed through a particulate filter, the dirt, dust and water droplets have been removed. Oil that is present is much smaller in size, and mostly passes though the particulate filter. The installation of a coalescing filter will provide for the removal of the majority of the fine oil aerosols that remain. The coalescing filter works differently than the particulate filters. The compressed air flows from inside to outside through the coalescing filter media. The term ‘coalesce’ means to ‘come together’ or ‘form one mass.’ The process of coalescing filtration is a continuous process where the small aerosols of oil come in contact with fibers of the filter media. As other aerosols are collected, they will join up and ‘come together’ and grow to become an oil droplet, on the downstream or outside surface of the media. Gravity will then cause the droplet to drain away and fall off the filter element.
Some important information to keep in mind –
Change the filter regularly, not just when the differential pressures exceeds recommended limits, typically 5 PSI
Coalescing filters will remove solids too, at a higher capture rate due to the fine level of filtration, using a pre-filter for solids will extend the life
Oil free compressors do not provide oil free air, as the atmospheric air drawn in for compression contains oil vapors that will cool and condense in the compressed air system.
If you would like to talk about oil removal filters or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
EXAIR offers 5 different styles of Safety Air Guns; Precision, VariBlast, Soft Grip, Heavy Duty and Super Blast. You can read more about the different styles of Safety Air Guns from a previous EXAIR blog “Not All Compressed Air Guns Are The Same” written by Justin Nichol. I will be targeting the accessories that can enhance the features of the EXAIR Safety Air Guns. These additions will make the Safety Air Guns more dynamic without sacrificing safety, efficiency, or durability.
OSHA 1910.242(b) requires chip guarding when compressed air is used for cleaning. EXAIR offers Chip Shields with our Safety Air Guns to meet this requirement. They are made from a polycarbonate disc which is practically unbreakable and protects the operator from any blow back of metal shavings or coolant. They come with a durable rubber grommet that squeezes onto the extensions and can be adjusted to maximize protection. We offer Chip Shields for the Precision, VariBlast, Soft Grip, and Heavy Duty Safety Air Guns with or without aluminum extensions.
For those far away targets and hard-to-reach areas, EXAIR offers aluminum extension pipes to attach to the Safety Air Guns. They can range from 6” (15 cm) to 72” (183 cm) in length. This light-weight and durable material allows for easy handling to reach high above your head or to span across unsafe areas. With the EXAIR air nozzles at the end, the blowing force is not sacrificed as the back pressure will generate a high velocity air stream. The aluminum extensions are offered with the Variblast, Soft Grip, and Heavy Duty Safety Air Guns. The Super Blast Safety Air Guns has the option for two different lengths of extensions, 3 feet (91cm) and 6 feet (183 cm).
In certain situations, you may need a way to blow air around a corner or in a tight space. The Stay Set Hose gives you that possibility of manually adjusting or re-adjusting the nozzles to target the correct areas. The hose has a “memory” function, and it will not creep or droop until you physically move it again. They come in lengths from 6” (15cm) to 36” (91cm), and they are offered with the Soft Grip and the Heavy Duty Safety Air Guns.
To get the proper amount of compressed air from the piping system to the Safety Air Guns, EXAIR offers a series of Coiled Hoses. They are made of a durable abrasion-resistant nylon material that is 12 feet long (3.6 meters). They have swivel fittings to allow for easy uncoiling, and a spring strain relief to keep the hose from kinking at the ends. The coiled design makes it easy to reach around the work area and retract back to the substation. This will help to keep the hose off the ground where potential dangers could occur. We offer 3 different connection sizes of 1/8” NPT, ¼” NPT, and 3/8” NPT. They can be used with our Precision, VariBlast, Soft Grip, and Heavy Duty Safety Air Guns. With the proper size, the Coiled Hoses can connect easily to the Safety Air Guns and supply the required amount of air with a minimal amount of pressure drop.
To improve the use of the Safety Air Guns, EXAIR offers a series of filters and regulators. The filters will remove dirty particles and liquid water from the compressed air that can affect the performance of the Safety Air Gun as well as contaminate the surface that you are cleaning. The regulators can control the amount of air pressure used for the Safety Air Gun; making them even more efficient. The idea for compressed air savings is to use the least amount of compressed air to do the job. If you only need 40 PSIG (2.8 Bar) to blow off an area, then you can save almost 40% of your compressed air as compared to doing that same job at 80 PSIG (5.5 Bar). The combination of a filter and regulator will allow you to control the proper amount of clean dry air to be used.
All of our Safety Air Guns are fitted with our engineered Air Nozzles which make them OSHA compliant for noise and dead-end pressure. With the accessories, you can optimize the use of the Safety Air Guns to better fit your application. If you need help in determine the correct Safety Air Guns and accessory items, you can contact an Application Engineer for help. If you are within the U.S. or Canada, you can take advantage of our 30-day unconditional guarantee to trial any of our stocked Safety Air Guns.