Siphon Fed Atomizing Nozzle Improves Roll Forming Process

Last week I worked with a gutter manufacturer who was looking for a way to spray a light coating of vanishing oil on the rollers of a forming machine. Roll forming is commonly used when needing to maintain a constant and consistent shape or feature across the length of the part. In this particular case, a sheet of aluminum, used as a cover for the gutter, is fed into the machine where it passes over a series of dyes that bends “ribs” and punches small holes into the part to keep leaves or debris from settling on top, while allowing the rainwater to pass through the holes and into the gutter.

They were needing to apply the oil to the rollers because they were starting to see some irregularities in hole size as well as some deformities to the shape of the ribs due to heat being generated during the forming process. The customer was interested in using some type of atomizing spray nozzle in the hopes that providing an atomized mist of liquid may provide for a faster evaporation of the oil so there wasn’t much residue left on the part before packaging.

After further discussing the details, they advised that they were going to have the oil in a container about 12″ below the machine but didn’t have a way to pressurize or pump the liquid to the nozzle. Once again, EXAIR has the perfect solution with our 1/4 NPT Siphon Fed Atomizing Nozzles. These nozzles are the ideal solution where pressurized liquid isn’t available as they use the compressed air to the draw the liquid into the nozzle, up to 36″ of suction height, and mix it internally to produce a mist of atomized liquid spray. For this particular application, the Model # SR1010SS was a good solution as it provides a low flow rate of only 0.8 GPH and a tight spray pattern to focus right at the rollers to avoid any waste or overspray.

sr1010ss

Model # SR1010SS Siphon Fed Round Pattern Atomizing Spray Nozzle – 303ss construction, fully adjustable flow rate

EXAIR offers an extensive range of Atomizing Nozzles that can be used for light coating applications, like above, or for wider coverage areas or higher flow rates. For help selecting the best option to fit your needs, contact one of our application engineers for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Cooling Punch Points with a Super Air Knife

A stamping facility had a high speed perforating operation. The idea was to punch holes into a matrix at a fast feed rate.  In their operation, they started to see issues with the punched holes, and they also noticed that the punch points were prematurely failing.  With a tight punch-to-matrix clearance, heat was building up from the friction.  This effect was galling the material and affecting the hole appearance and dimensions.  They also noticed heat damage to the punch points.  They either had to slow their process down, or find a way to cool the punch points.  They contacted EXAIR to see if we could help.

To remove heat, you need to have a fluid moving across the material to carry the heat away. For this customer, the fluid would be air.  Just like a hot cup of coffee, you can cool it by blowing across the top of it.  In this instance, EXAIR can blow a lot of air with using very little amount of compressed air.  Because of the gap opening of the tool die was narrow, I suggested the Super Air Knife.  It has a compact design and can blow nicely between the upper and lower die.  With slight modifications, they were able to mount the Super Air Knives right into the base set.  Because the tool die was a “bowl” type design, I suggested that they should use two pieces of the model 110206 Super Air Knife.  They could mount one to each side to make sure to hit all the punch points.  (Reference the picture below).

Punch Press with a Super Air Knife

Punch Press with a Super Air Knife installed

EXAIR Super Air Knives are the most efficient compressed air knives in the market. It is designed to have a 40:1 amplification ratio.  That means for every one part of compressed air, it will entrain 40 parts of the free ambient air.  As with the coffee reference above, the more air that you can blow, the better the cooling effect.  With the Super Air Knife, we can reach a velocity of 11,800 feet per minute at 80 PSI.  After the customer installed the Super Air Knives, they were able to increase production by 10%.  Also, they found that the punch points were lasting twice as long.  They were so impressed with the effectiveness of the Super Air Knives, they mounted them to all their punch press machines.

Super Air Knife

Super Air Knife

If you find that heat is affecting your process, EXAIR could have a product to help you. We have a variety of efficient air movers to cool your parts.  As for this customer above, we were able to increase production and extend the life of their tools.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Wearing Out Your Sole

3925 Adjustable Spot Cooler

3925 Adjustable Spot Cooler

A shoe manufacturer had a special abrasion test that was required by his customer to test special rubber compounds. The set up was to run a small chain across the bottom of the rubber sole.  The chain was looped to continuously rub against the sole of the shoe.  As they began their wear testing, they noticed that the chain was getting hot from the friction.  The heat would get high enough to change the composition of the rubber and cause a premature failure.  To properly test for wear, they needed to cool the chain.

As they discussed their application with me, they required the chain to be at a specific temperature. I suggested the model 3925 Adjustable Spot Cooler System.  This system comes with a dual point hose kit, a magnetic base, a filter separator, and two additional generators.  The generators of the Adjustable Spot Cooler are a piece which controls the total volume of air through the cooler. They can be switched in and out to produce more or less cooling capacity of the Adjustable Spot Cooler. The main concern was to keep the chain temperature constant.  With a temperature control knob and the additional generators, they could dial in the cooling capacity to keep the chain at the desired temperature.  If the chain was too cold, the sole would not wear properly, and if the chain was too hot, it would change the composition of the rubber material.

They mounted the Adjustable Spot Cooler to the abrasion machine with the dual points blowing on each side of the chain. They quickly noticed that they could keep the chain cooler than the specified temperature.  As a trial, they replaced the generator to the 30 SCFM (850 SLPM) flow rate.  This increased the cooling capacity of the Spot Cooler.  With the higher cooling capacity, they could increase the speed of the abrasion machine to shorten the failure cycle.  This was a great benefit to have as they were testing different rubber compounds to determine the best product; a pronounced advantage in research and development.

If you find out that heat is causing problems in your application, you can contact an Application Engineer at EXAIR for help in finding the correct cooling product. In this instance, friction was the culprit and the Adjustable Spot Cooler was the solution.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Let’s Cool Things Down With Heat Transfer Equations

When it comes to cooling products, we get many questions on what would be the best method. Generally with larger parts with heavy mass and large surface areas, we would recommend the Super Air Amplifiers, Super Air Knives or Super Air Nozzles. We have to look at many factors to determine the correct method, but if look at the mass of the part, the ambient conditions, the speed of the conveyor, and the change in temperature, we can get a good start in setting up an application.

In determining a good estimate, we use a couple of heat equations to help. As with any customer, you want to make sure you have as much information to get a good platform to start. We use two equations to begin. The first equation is used for the product that needs to be cooled.

Equation 1

q = m * Cp * (T2 – T1)

Where:
q – heat (BTU) or (Kcal)
m – Mass (Lb) or (Kg)
Cp – specific heat (BTU/Lbm oF) or (Kcal/Kg oC)
ΔT – Temperature (oF) or (oC)

Once we have the amount of heat that we need to remove, then we can look at the product to cool it. With Super Air Amplifiers, we use an equation that is used in fan cooling. This is the second equation.

Equation 2

h = 1.08Qs(T2 – T1)       OR                h = 0.33Qs(T2 – T1)

Where:
h – heat rate (BTU/hr)                                   h – heat rate (Watts)
Qs – Flow (SCFM)                  OR                   Qs – Flow (NM^3/hr)
ΔT – Temperature (oF)                                  ΔT – Temperature (oC)

 

As an example, we have an aluminum part that came out of a baking oven at 400 oF (204 oC), and we want to cool the part down to 100 oF (38 oC) for handling.  If we give the part a mass of 20 lbs. (9.1 Kg), we can determine how long we would need to cool the part. The specific heat, Cp, of aluminum is 0.22 BTU/Lbm oF or Kcal/Kg oC. Applying this to Equation 1, we get the following:

q = 20 lbs * (0.22 BTU/lb/oF) *(400 oF – 100 oF)

q = 1,320 BTU

Or

q = 9.1 Kg * (0.22 Kcal/Kg/ oC) * (204 oC – 38 oC)

q = 332 Kcal

This tells us how much heat we would need to remove in order to handle. To keep going along with this example, we will use the 120021 Super Air Amplifier. With the large amplification level, it has a flow of 436 SCFM (740 NM^3/hr) at 6” away. To produce that volume, it only uses 8.1 scfm of compressed air at 80 psig. There are a couple of things that we should consider with our estimation. Ideally, we will want to be at a distance where the velocity will be between 1,700 to 2,500 fpm (8.6 to 12.7 mps). This gives us the best velocity for the maximum cooling rate. Depending on certain situations, you may have to add a little more time for cooling if the velocity is too high or too low. With the 120021 Super Air Amplifier, a distance of 18” from your target will give you a velocity close to 1,850 fpm (9.4 mps). The other consideration is the rate of heat loss. The bigger the temperature difference, the faster it will cool. As you get near the target temperature, the rate change becomes smaller. With that, I usually take the average temperature as an estimate. Using our example above, it would be (400 + 100)/2 = 250 oF, or (204 + 38)/2 = 121 oC. The other estimation will be the temperature of the ambient air. It will be cooler as it first hits the target and then heat up. If we add roughly 7 oF (4 oC) to the ambient air temperature because of the velocity, then the ambient temperature would become 68 + 7 = 75 oF (20 + 4 = 24 oC). With Equation 2, we will get the following:

h = 1.08 * 436 SCFM *(250 oF – 75 oF)

h = 80,404 BTU/hr

Or

h = 0.33 * 740 NM^3/hr * (121 oC – 24 oC)

h = 23,687 Watts or 20,372 Kcal/hr

With Equation 1 and Equation 2, we can estimate the amount of time needed to cool the part. In having to remove 1,320 BTU at a rate of 80,404 BTU/hr, the equation will give us 1,320 BTU/ (80,404 BTU/hr) = 0.016 hr or 1 minute.  In metric units, 332 Kcal/(20,372 Kcal/hr) = 0.016 hr or 1 minute. This means that we will have to keep the target in the air stream for about 1 minute. Depending on the geometry of the part, the angle of the amplifier, and the speed of the conveyor, we may need multiple Super Air Amplifiers. As I mentioned before, these are estimations, but it will help in getting an idea for your project. You can always contact the Application Engineers at EXAIR for any help.

Cooling with Air Amplifiers

Cooling with Air Amplifiers. The Super Air Amplifiers are mounted across the top of this connecting rod/piston assembly. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Adjustable Air Amplifier Removes Heat, Protects Thermocouple

I was working with a customer recently who had a fairly interesting application that I’d like to share with you. The customer operates a steel furnace and they have an automatic, liquid steel temperature probe that does not have sufficient time to cool down before they take another temperature measurement which should be a minimum of 5 minutes.

The probe consists of a 6 foot long, ¾” pipe, attached to the end of a 12 foot long beam. The beam lowers the pipe with the probe attached into the steel bath to take the temperature (see sketch below). The pipe is covered with a consumable, cardboard type of tube (pictured above) which is the thermocouple.  A contact block with wiring inside the pipe connects to the thermocouple. This contact block becomes heat damaged because the pipe does not have enough time to cool between temperature measurements.

steel temperature

The customer was originally thinking about using a Super Air Knife to cool the probe and pipe between temperature measurements. After discussing options, the customer took our advice and went with (2) of our 2” Stainless Steel Adjustable Air Amplifiers (model 6042) instead. The Air Amplifiers are able to be mounted at the “parked” position of the pipe / probe and actuated to blow down the pipe and thermocouple length-wise during this time.

The high velocity airflow was able to carry enough heat out of the assembly between temperature measurements that the contact block was no longer becoming overheated and damaged as it was before. We decided to suggest this option to the customer because the air usage for this option was less than that of a 60” long Air Knife and the Stainless Adjustable Air Amplifier has temperature rating of 400°F which was easily able to withstand the heat in the application.

Neal Raker, Application Engineer
nealraker@exair.com

 

 

Full Flow Air Knife Increases Airflow By 3000%

Condensor Housing

Inside of the housing of the photo above is an EXAIR Full Flow Air Knife. The housing serves as a shield to a condenser on a specially built machine for one of the Big Three U.S. auto manufacturers. The purpose of the air knife within the housing is to supplement heat removal by passing large volumes of ambient air over the condenser, thereby helping to return the gaseous fluid to a liquid state.

When compressed air was supplied to the air knife in this photo, there was very little airflow. Knowing that there was something amiss, and that an Application Engineer could offer potential solutions, the OEM called in to EXAIR.

Immediately upon seeing the photo, the root cause of the problem was evident. There was no ambient air available for the air knife to entrain. It looks like an attempt was made to open the housing *in the bent edges at the top of the housing), but it was not enough.

Removing the housing from the machine revealed the following internal installation.

Condensor Housing Internal

With such a setup, there was no entrainment of ambient air, and the total airflow was only a fraction of what it should be. Removing the current shield and fabricating an alternate design which allows ambient airflow solved the problem in this application. Compressed air use remained low, and total airflow was increased by 3000%.

EXAIR products keep compressed air use low and performance to a maximum. For help with your application, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

EXAIR Can Customize for Your Application

Once again this week, I had a customer call in with a special request on one of our products.  The customer had purchased a 6030 Adjustable Air Amplifier to cool plastic components after they were formed in a previous process.  These components are made continuously and the only way to test the cooling capabilities was during a production run.  If there was any error in the system, a whole batch of product was rejected, so the customer needed to be able to fine tune the process easily.  The space was very confined, so the customer had taken the 3/4″ outlet and connected a 3/4″ hose with hose clamps in order to direct the air to the proper area.  From the 3/4″ hose, they had necked down the line to 3/8″ hose to fit into their process.  By necking down the outlet of the air amplifier, the customer was limiting the output of the 6030, but it was enough air to get there job done.  Now that he had successfully used the 6030, the customer wanted to rollout the idea to other product lines and create a more robust system than hose clamps and homemade reducers.  Fortunately, for this customer and many others, EXAIR has the skill and flexibility to manufacture custom solutions.

air amp

The customer wanted to roll the project out into 25 production lines, and create a more robust system.  The first idea that came to mind was using a threaded Line Vac to replace the Air Amplifier.  This would be a stock item that would produce a similar amount of air flow as the air amplifier through a 3/8″ hose.  Obviously, the Air Amplifier would produce more airflow in free air, but since we are restricting that flow with a 3/8″ hose, the Line Vac and the Air Amplifier would produce similar air flow in this application.  Unfortunately, the customer didn’t have the ability to test the process with the Line Vac, because of his production schedule and the risk of losing a batch of product during the testing.  Because of these requirements, the customer asked us to produce (25) Special Air Amplifiers with threaded outlets to replace his 6030 that he was currently using.  The Adjustable Air Amplifier would give the customer the ability to adjust the air flow by changing the air gap in the Air Amplifier to his exact specification.  This adjustability means he can set the Air Amplifier to meet his current requirements, and adjust if the conditions change on his production line.  Also, the system would now be threaded so he could install hard pipe to make a permanent and robust system throughout the facility.

Special Air Amplifier

Dave Woerner
Application Engineer
davewoerner@exair.com
@EXAIR_DW

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