The first step to optimizing compressed air systems within an industrial facility is to get a known baseline. To do so, utilizing a digital flowmeter is an ideal solution that will easily install onto a hard pipe that will give live readouts of the compressed air usage for the line it is installed on. There is also an additional feature that we offer on the Digital Flowmeters that can help further the understanding of the compressed air demands within a facility.
The Pressure Sensing Digital Flowmeters are available from 2″ Sched. 40 Iron Pipe up to 8″ Sched. 40 Iron Pipe. As well as 2″ to 4″ Copper pipe. These will read out and with the additional Data Logger or Wireless Capability options record the information. When coupled with the wireless capability an alarm can be set for pressure drops that give live updates on the system as well as permits data review to see trends throughout the day of the system.
Generating a pressure and consumption profile of a system can help to pinpoint energy wasters such as timer-based drains that are dumping every hour versus level based drains that only open when needed. A scenario similar to this was the cause of an entire production line shut down nearly every day of the week for a local facility until they installed flowmeters and were able to narrow the demand location down to a filter baghouse with a faulty control for the cleaning cycle.
If you would like to discuss the best digital flowmeter for your system and to better understand the benefits of pressure sensing, please contact us.
When evaluating processes that utilize compressed air and adhering to the Six Steps to Compressed Air Optimization, intermediate storage proves to be a critical role coming in at step number five. Intermediate storage tanks may already be in place within your facility and often times can be implemented as modifications to aid existing lines that are struggling to maintain proper availability of compressed air to keep the line at peak performance.
When determining whether or not a production line or point of use compressed air operation would benefit from a receiver tank/intermediate storage we would want to evaluate whether the demand for compressed air is intermittent. Think of a receiver tank as a capacitor in an electrical circuit or a surge tank in a water piping system. These both store up energy or water respectively to deliver to during a short high demand period then slowly charge back up from the main system and prepare for the next high demand. If you look from the supply point it will see a very flattened demand curve, if you look from the application side it still shows a wave of peak use to no use.
One of the key factors in intermediate storage of compressed air is to appropriately size the tank for the supply side of the system as well as the demand of the application. The good news is there are equations for this. To determine the capacity, use the equation shown below which is slightly different from sizing your main compressed air storage tank. The formulate shown below is an example.
V – Volume of receiver tank (ft3 / cubic feet)
T – Time interval (minutes)
C – Air demand for system (cubic feet per minute)
Cap – Supply value of inlet pipe (cubic feet per minute)
Pa – Absolute atmospheric pressure (PSIA)
P1 – Header Pressure (PSIG)
P2 – Regulated Pressure (PSIG)
One of the main factors when sizing point of use intermediate storage is, they are being supplied air by smaller branch lines which cannot carry large capacities of air. That limits your Cap value. The only way to decrease the V solution is to increase your Cap. The other key point is to ensure that all restrictions feeding into the tank and from the tank to your point of use are minimized in order to maintain peak performance.
“You can’t manage what you don’t measure” is a well-known axiom in engineering & process improvement circles. We talk to callers every day who are keen on conserving compressed air use in their facilities by making a few tweaks, considering a complete overhaul, or more often, some point in between. Bottom line (literally) is, compressed air isn’t cheap, so small gains in efficiency can add up. And large gains can be complete game-changers…following our Six Steps To Optimizing Your Compressed Air System has resulted in users being able to shut down 50 and 100 HP air compressors, saving thousands of dollar A MONTH in operating costs.
Step #1 is measurement, and that’s where the EXAIR Digital Flowmeter comes in. They’re easy to install, highly accurate, extremely reliable, and available for just about any size pipe used for compressed air distribution. They can output a 4-20mA signal straight from their PCB board, or serial comms (RS485) through an optional control board. USB Data Loggers and Summing Remote Displays have proven to be value-added accessories for data management as well.
If you want to go wireless, we can do that too: using ZigBee mesh network protocol, a radio module is installed in the Digital Flowmeter with wireless gateway to transmit data to an Ethernet connected gateway. The transmitting range is 100 ft (30 meters,) and the data can be passed from one radio module to another, allowing for multiple Digital Flowmeter installations to extend the distance over which they can communicate with the computer you’re using for central monitoring. Advantages include:
As mentioned in my post last week. The supply side of compressed air systems within a facility is critical to production. The quality of air produced by your compressor and sent to the demand side of the system needs to be filtered for both moisture and particulate. One method to dry the air, that is the topic for this blog, is deliquescent type dryers.
These dryers operate like an adsorbent dryer such as a desiccant medium dryer. The main variance is that the drying medium (desiccant) actually undergoes a phase change from solids to liquids. Because of this the material is used up and cannot be returned to its original state for reuse. The liquids formed by the desiccant dissolving in the removed water vapor are then filtered out of the air stream before it is passed on to the demand side of the air system.
There are many compounds that are used to absorb the moisture in the wet compressed air. A few options are potassium, calcium, or sodium salts and many that contain a urea base. The desiccant compound must be maintained at a minimum level for the dryer to contain enough media to successfully dry the air.
These dryers are generally a single tank system that is fed with compressed air from a side port near the bottom of the tank. The air then travels up past drip trays where the desiccant and water mixture fall and ultimately ends up in the bottom of the tank. The air then goes through a material bed that must be kept at a given level in order to correctly absorb the moisture in the air. The dry air is then pushed out the top of the tank.
As the desiccant material absorbs the liquid from the compressed air flowing through the tank it falls onto the drip trays and then into the bottom of the tank where it is drained out of the system. This process can be seen in the image below.
The dew point that this style dryer is able to achieve is dependent on several variables:
Compressed air temperature
Compressed air pressure / velocity
Size and configuration of the tank
Compression of the absorption media
Type of absorption media and age of media
These dryers are simplistic in their design because there are no moving parts as well as easy to install and carry a low startup cost.
Some disadvantages include:
Dewpoint range 20°F – 30°F (Again this is according to the media used.)
Dissolved absorption material can pose a disposal issue as it may not be able to be simply put down a drain
Replacement of the absorption material
Even with disadvantages the ability to supply the demand side of a compressed air system for a production facility is key to maintaining successful operations. If you would like to discuss any type of compressed air dryer, please contact us.