I like some better than others, but I don’t believe I’ve ever had bad pizza. That’s why I was pretty excited when I got to talk to a caller from a popular pre-packaged pizza crust maker. When these crusts leave their oven, they spray a coating of seasoned oil on them. This not only flavors, but preserves the quality from the time they make & package them to the time I celebrate life with a tasty slice, right out of my oven.
They were using inexpensive liquid-only nozzles that led to an inconsistent application of the oil…sometimes too much; other times, too little. And, it was always spraying, even in between the individual crusts as they came down the conveyor, leading to wasted oil that had to be cleaned up later.
They were already familiar with our Super Air Nozzles, as they had several Model HP1125SS 2″ High Power Flat Super Air Nozzles in use for blowing off the packages prior to labeling, so the caller asked if we might have a solution for the oil too.
After considering the size of the crust and the distance at which they needed to install the nozzle, they decided to try a Model AF2010SS Internal Mix Flat Fan Pattern No-Drip Atomizing Spray Nozzle. This applies a consistent and even coating of oil, and, by feeding a signal from the oven controls into a solenoid valve in the compressed air supply line, they’ve eliminated the excess spray, leading to savings in material cost and cleanup time.
If you’d like to know more about how EXAIR Atomizing Spray Nozzles can save you time, mess, and liquid, give me a call.
A receiver tank is a form of dry compressed air storage in a compressed air system. Normally installed after drying and filtration, and before end use devices, receiver tanks help to store compressed air. The compressed air is created by the supply side, stored by the receiver tank, and released as needed to the demand side of the system.
But how does this work?
The principle behind this concept is rooted in pressure differentials. Just as we increase pressure when reducing volume of a gas, we can increase volume when reducing pressure. So, if we have a given volume of compressed air at a certain pressure (P1), we will have a different volume of compressed air when converting this same air to a different pressure (P2).
This is the idea behind a receiver tank. We store the compressed air at a higher pressure than what is needed by the system, creating a favorable pressure differential to release compressed air when it is needed. And, in order to properly use a receiver tank, we must be able to properly calculate the required size/volume of the tank. To do so, we must familiarize ourselves with the receiver tank capacity formula.
Receiver tank capacity formula
V = ( T(C-Cap)(Pa)/(P1-P2) )
V = Volume of receiver tank in cubic feet
T = Time interval in minutes during which compressed air demand will occur
C = Air requirement of demand in cubic feet per minute
Cap = Compressor capacity in cubic feet per minute
Pa = Absolute atmospheric pressure, given in PSIA
P1 = Initial tank pressure (Compressor discharge pressure)
P2 = minimum tank pressure (Pressure required at output of tank to operate compressed air devices)
Let’s consider an application with an intermittent demand spike of 50 SCFM of compressed air at 80 PSIG. The system is operating from a 10HP compressor which produces 40 SCFM at 110 PSIG, and the compressed air devices need to operate for (5) minutes at this volume.
We can use a receiver tank and the pressure differential between the output of the compressor and the demand of the system to create a reservoir of compressed air. This stored air will release into the system to maintain pressure while demand is high and rebuild when the excess demand is gone.
In this application, the values are as follows:
V = ?
T = 5 minutes
C = 50 CFM
Cap = 40 SCFM
Pa = 14.5 PSI
P1 = 110 PSIG
P2 = 80 PSIG
Running these numbers out we end up with:
This means we will need a receiver tank with a volume of 24.2 ft.³ (24.2 cubic feet equates to approximately 180 gallons – most receiver tanks have capacities rated in gallons) to store the required volume of compressed air needed in this system. Doing so will result in a constant supply of 80 PSIG, even at a demand volume which exceeds the ability of the compressor. By installing a properly sized receiver tank with proper pressure differential, the reliability of the system can be improved.
This improvement in system reliability translates to a more repeatable result from the compressed air driven devices connected to the system. If you have questions about improving the reliability of your compressed air system, exactly how it can be improved, or what an engineered solution could provide, contact an EXAIR Application Engineer. We’re here to help.
I wrote a blog a few weeks ago about increasing efficiency with EXAIR Super Air Nozzles. In the application for that blog we used engineered nozzles to place open pipes, resulting in an efficiency increased of ~65%. This week’s installment of efficiency improvements boasts similar figures, but through the replacement of misused liquid nozzles rather than open pipe.
The image above shows a compressed air manifold with a number of nozzles. BUT, the nozzles in this manifold are not compressed air nozzles, nor do they have any engineering for the maximization of compressed air consumption. These are liquid nozzles, usually used for water rinsing.
In this application, the need was to blow off parts as they exit a shot blasting machine. When the parts exit the shot blasting process they are covered in a light dust and the dust needs to be blown away. So, the technicians on site constructed the manifold, finding the liquid nozzles on hand during the process. They installed these nozzles, ramped up the system pressure to maintain adequate blow off, and considered it finished.
And, it was. At least until one of our distributors was walking through the plant and noticed the setup. They asked about compressed air consumption and confirmed the flow rate of 550 m³/hr. (~324 SCFM) at 5 BARG (~73 PSIG).
The end user was happy with the performance, but mentioned difficulty keeping the system pressure maintained when these nozzles were turned on. So, our distributor helped them implement a solution of 1101SS Super Air Nozzles to replace these inappropriately installed liquid nozzles.
By implementing this solution, performance was maintained and system pressure was stabilized. The system stabilization was achieved through a 61% reduction in compressed air consumption, which lessened the load on the compressed air system and allowed all components to operate at constant pressure. Calculations for this solution are shown below.
Compressed air consumption of (9) model 1101SS @ 5.5 BARG (80 PSIG): 214 m³/hr. (126 SCFM)
Total compressed air consumption of 1101SS Super Air Nozzles:
Air consumption of 1101SS nozzles compared to previous nozzles:
Engineered air nozzles saved this customer 61% of their compressed air, stabilized system pressure, improved performance of other devices tied to the compressed air system, and maintained the needed performance of the previous solution. If you have a similar application or would like to know more about engineered compressed air solutions, contact an EXAIR Application Engineer.
I had the pleasure of discussing a spot cooling application with a customer this morning. He wanted to get more flow from his Adjustable Spot Cooler, but still keep the temperature very low. He machines small plastic parts, and he’s got enough cold flow to properly cool the tooling (preventing melting of the plastic & shape deformation) but he wasn’t getting every last little chip or piece of debris off the part or the tool.
After determining that he had sufficient compressed air capacity, we found that he was using the 15 SCFM Generator. The Adjustable Spot Cooler comes with three Generators…any of the three will produce cold air at a specific temperature drop; this is determined only by the supply pressure (the higher your pressure, the colder your air) and the Cold Fraction (the percentage of the air supply that’s directed to the cold end…the lower the Cold Fraction, the colder the air.)
Anyway, the 15 SCFM Generator is the lowest capacity of the three, producing 1,000 Btu/hr of cooling. The other two are rated for 25 and 30 SCFM (1,700 and 2,000 Btu/hr, respectively.)
He decided to try and replace the 15 SCFM Generator with the 30 SCFM one…his thought was “go big or go home” – and found that he could get twice the flow, with the same temperature drop, as long as he maintained 100psig compressed air pressure at the inlet port. This was more than enough to blow the part & tool clean, while keeping the cutting tool cool, and preventing the plastic part from melting.
If you’d like to find out how to get the most from a Vortex Tube Spot Cooling Product, give me a call.
Earlier this morning I received a phone call from a gentleman in search of a more efficient compressed air solution. The application was to remove thermoformed plastics from a mold immediately after the mold separates. In the current state, the application is consuming ~40% of the available compressed air in the facility through the use of (9) ¼” open pipes, consuming a confirmed 288 SCFM at 60 PSIG. Due to the use of an open pipe, this customer was facing a safety and noise concern through the existing solution.
After discussing the application need and the desire to reduce compressed air use, reduce noise, and add safety, we found a suitable solution in the 1101 Super Air Nozzle. Installing (9) of these EXAIR nozzles will reduce the compressed air consumption by over 65%!!! Calculations for this savings are below.
Existing compressed air consumption: 288 SCFM @ 60 PSIG
Compressed air consumption of model 1101 @ 60 PSIG: 11 SCFM
Total compressed air consumption of (9) 1101 nozzles:
This is the percentage of air which the new EXAIR solution will consume. To put it another way, for every 100 SCFM the current solution consumes, the EXAIR solution will only require 34.38 SCFM. Installing these EXAIR nozzles will result in lower operational cost, lower noise levels, and increased safety for this customer – all while maintaining or improving the performance of the blow off solution in this application.
EXAIR Application Engineers are well versed in maximizing efficiency of compressed air systems and blow off needs. If you have an application with a similar need, contact an EXAIR Application Engineer. We’ll be happy to help.
Albert Einstein famously said, “Nothing happens until something moves.” And unless it’s in a perfect vacuum when it moves, there’s gonna be friction. Especially if it’s in contact with something else besides air. And where there’s friction, there’s heat. This pretty much applies to almost every single evolution in the manufacture of…well, just about everything.
I’m probably not telling you anything you don’t already know, but heat can be a BIG problem. It can:
Shorten tool life. Not only do worn tools take longer to cut, they can also present safety issues. You can get hurt WAY worse by a dull blade than a sharp one.
Cause thermal expansion. If you’re machining something to a precise tolerance, and friction heat causes it to grow, it won’t be the same size when it cools down.
Melt plastics. And even softer metals. This isn’t good for the part…or the tool, either.
Those are just a few of the problems heat causes in manufacturing operations, and they’ve been traditionally addressed with mist (liquid) coolants. And they work just fine…most of them are water-based, and if you want to get heat out of a solid piece of something, water will do the job VERY quickly. Other additives in the coolant provide a measure of lubricity, corrosion control, emulsion prevention, etc. It’s easy, well-known, and time-tested. There are some drawbacks, however:
It can be messy. When a part (or a tool) in motion gets sprayed down with liquid, it tends to fling that liquid all over the place. That’s why most machines fitted with mist coolant have spray shields.
Not only is it a hassle to clean up, if you don’t stay on top of the clean-up, it can lead to slip hazards.
Speaking of hazards, if you can smell that mist (and you know you can,) that means you’re breathing it in too. Remember the lubricants, corrosion inhibitors, emulsion preventers, etc., I mentioned above? Yeah…they’re not all what you might call “good for you.”
Recirculation systems are common, which means the coolant sump is gathering solids, so the lines and/or spray nozzles can clog and be rendered useless.
They incorporate EXAIR’s Vortex Tube technology to produce a stream of cold air.
They’re reliable. There are no moving parts; if you supply them with clean, dry air, they’ll run darn near indefinitely, maintenance free.
They’re quick & easy. With a built-in magnet for mounting and a flexible cold air hose, you can be be blowing cold air right where you want it as quickly as you can attach an air hose and open the valve.
Speaking of opening the valve, that’s all it takes to run a Cold Gun. They’re producing cold air at rated flow and temperature, right away. No “ramp up” time to get into operation.
They’re clean. That cold air stream just becomes…well, air. No mess. No slip. No clean up. No smell. No problem.
We’ve got four Models to choose from, depending on the nature of the application:
If you need to cool parts or tools down, and want it to be effective and clean, give me a call.
Recently we have blogged about Compressed Air Dryers and the different types of systems. We have reviewed the Desiccant and Refrigerant types of dryers, and today I will discuss the basics of the Membrane type of dryers.
All atmospheric air that a compressed air system takes in contains water vapor, which is naturally present in the air. At 75°F and 75% relative humidity, 20 gallons of water will enter a typical 25 hp compressor in a 24 hour period of operation. When the the air is compressed, the water becomes concentrated and because the air is heated due to the compression, the water remains in vapor form. Warmer air is able to hold more water vapor, and generally an increase in temperature of 20°F results in a doubling of amount of moisture the air can hold. The problem is that further downstream in the system, the air cools, and the vapor begins to condense into water droplets. To avoid this issue, a dryer is used.
Membrane Dryers are the newest type of compressed air dryer. Membranes are commonly used to separate gases, such as removing nitrogen from air. The membrane consists of a group of hollow fiber tubes. The tubes are designed so that water vapor will permeate and pass through the membrane walls faster than the air. The dry air continues on through the tubes and discharges into the downstream air system. A small amount of ‘sweep’ air is taken from the dry air to purge and remove the water vapor from inside the dryer that has passed through the membrane tubes.
Resultant dew points of 40°F are typical, and dew points down to -40°F are possible but require the use of more purge air, resulting in less final dry compressed air discharging to the system.
The typical advantages of Membrane Dryers are-
Low installation and operating costs
Can be installed outdoors
Can be used in hazardous locations
No moving parts
There are a few disadvantages to consider-
Limited to low capacity systems
High purge air losses (as high as 15-20% to achieve lowest pressure dew points
Membrane can be fouled by lubricants and other contaminants, a coalescing type filter is required before the membrane dryer.
If you have questions about getting the most from your compressed air system, or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.