PERC Updates
Independent Test Results
February 9, 2012
Lompoc (CA) School District performed a CO test of the Lompoc City's PERC unit. This is a very important, independent study and they have agreed to let us use it. Click here to view the report.
Pest Control Services
June 20, 2011
We are pursuing working with the Pest Control industry to develop units that are easier to use, fast to start a job and fast to finish a job and go on to the next job. We have large reels with 300’ hoses. Reports from the field have said that the motorized reels are hard to unreel though nice to reel back up. They are very expensive.
For now, I recommend that the manual reels are ordered on new units. They are much more economical, not near as much to go wrong and they have in all probability a shorter turn around time on the job.
Allen
Rules of thumb for "What unit do I need?"
February 15, 2011
I recently did a time cost production analysis for a customer in helping him decide what unit to buy for his acreage.
This is a difficult problem for those that would max out a 206 but have minimal acreage for a 412. And of course the same is true with the 412 compared to the 620.
Working with several custom operators we have come up with the mounds per acre in a gopher infested field that would constitute a fairly mild infestation. We determined that 20 to 25 mounds per acre will allow an operator using the PERC 412 to treat from 3 to 3 1/2 acres an hour. This would calculate out to about one minute per mound. Thus, if there were 40 mounds per acre, you could expect to treat about 1-1/2 acres an hour with the 412 and so on. The 620 can cover about about 1.7 times the area covered by the 412 in any given time frame. The real advantage to the 620 is that it has 40,000 ppm of CO in the exhaust gas while the 412 has about 25,000 PPM of CO. The 206 tests at 20,000 ppm of CO.
The determining factor is cost per acre of the machine, labor availability and of course availability of capital. Most farmers have shown that they can justify the capital purchase of their PERC unit when the per acre cost of the machine is between $10 and $40. Getting the dirt out of the hay, reductions of breakdowns in the field from gopher mounds and a faster, smoother harvest are factors used when justifying the cost of the machine.
Consequently, the recommended acreages for each machine are as follows:
206 and the 206T up to 200 acres
412 200 to 1,000 acres
620 1,000 to 2,000 acres (custom operators and large operations that can have a full time operator can cover up to about 3,000 acres in a 12 month time frame weather permitting.)
Model updates:
February 15, 2011
We have done a lot of machine improvements in the last year. First we have replaced the SS coil flex tubing with a seamless ribbed flex tubing that delivered the gas to the cooling coils and from the cooling coils to the compressor. (206 and 412 only.) To date, this looks like a life of the machine improvement. We have not changed the flex tubing on the 620 because of the additional cost of the ribbed tubing and the reduced vibration of the 620 has prevented the flex tubing from showing any failure.
The old load geni has been replaced by a pilot valve. It is simpler, cheaper, filtered and has not had a failure in several months.
The belting we used for the vibration pads has been replaced with rubber impact material that does not have any cording. it is working great and has reduced vibration.
You will notice that the wand holders are better located, has one wand per tube and gives a lower profile. (412 and the 620.)
We are in the process of offering 300' reels for the 206 and the 412. These are targeted for the pest control industry, an area we are just getting started marketing in. The profits from treating urban yards are astounding. A skid mounted 412 is on the drawing board and looks to be popular to set in a small pickup for pest control businesses. It is not recommended for commercial agriculture, efficiency in the field is reduced in comparison to the trailered unit pulled with an ATV.
Carbon Monoxide testing
April 4, 2010
We have recently purchased a new Carbon monoxide tester. We can test CO in ppm up to 10,000 ppm and above that in percent. We are testing every new unit prior to delivery and to say the least, it is very interesting. First, no two motors have tested alike. The 13 hp motors will test from 14,000 ppm to 21,000 ppm. The 6.5 hp motors have very little test history yet, but it would seem they will test in the 15,000 ppm range. The twin V 20 hp motors are testing from 30,000 to 40,000 ppm. We have tried and will continue to test methods to increase the CO levels. Soaking the foam air filter cover in oil and wringing out the excess oil seems to not effect the motors running and does increase the CO by about 1,000 ppm. Choking the motor by about 1/8″ to 1/4″ has had a dramatic effect on the CO, from 20 to 40 percent increase. This does not seem to effect the power of the motor.
I have advised those that call in with poor kill rates to concentrate their treatment area at any one setting to a local area of 20' or less. Do not spread out the wands because that will only reduce the toxicity level in all the burrows. Remember, we are building up the toxicity level by probing a single burrow system multiple times. A single probe in a separate burrow system will not kill the gopher but will take CO away from the other probes.
As we gather more information on our testing of the CO levels, I will post it here.
Allen
Flex tubing on all PERC’s.
January 28, 2010
Some of the most valuable information I get comes from the field. Probably the most perplexing has been units several months old that seemed to decrease in their toxicity to kill gophers. The answer had to be air contamination of the exhaust gasses, but everything was tight with no visible air leak. When the unit was new, it worked great. After several months, there seemed to be more and more gopher mounds showing up in the area treated.
I figured it out, but it took some serous head scratching!!
The contamination problem was (and is) coming from the SS flex tubing from the motor to the cooling coils and from the cooling coils to the compressor. Vibration has always been a serous consideration and it reared its ugly head once more.
The flex tubing is really a long strip of light weight stainless steel that is formed to hook together in a spiral. Tolerances are tight and when new, it is close to air tight. But with use, the units vibration causes continue flexing of the tubing and causes the joints to create very small cracks that will leak.
There is positive pressure inside the tube from the motors exhaust and it has been assumed that this positive pressure would overcome any cracks that developed from use. But we missed one very important fact. The positive pressure works great when it is blowing towards the hooked joint. When it is blowing away from the hooked joint, it causes a vortex in the V formed by the joints which in turn creates a venturi effect. This vortex will actually cause a vacuum that will draw outside air into the exhaust stream in the flex tube. This creates a venturi effect and introduces air contamination to the exhaust reducing its ability to kill rodents.
On the 620 and the 412, this is very easy to fix. If the unit is within a year old, the flex tube can be inspected and if the folded portion of the joints point away from the motor or exhaust flow, it will not suck air. If it is pointed towards the motor, it will suck air.
If the fold is pointed towards the motor, take the clamps loose and reverse the direction of the flex tube and re-clamp it. If the unit is over a year old with heavy use, the tubes should be replaced. Either we can furnish the tubes or they can be bought from most auto supply stores.
The flex tubes on the 206 pose a bit of a complication. I have not found exhaust pipe clamps that will fit on the one inch tubing we use. While we can furnish the rings, the tool needed to tighten them up is the band-it junior and is a special tool. Heavy duty screw type clamps can be used in combination with a high temperature gasket sealant. Any exhaust gas that leaks will be minor and in this situation, air will not be sucked into the exhaust stream contaminating it.
I am drawing up an illustration that will have both graphic form and written instruction that we will mail to PERC owners. I appreciate your patience and want you to know that we are dedicated to keeping all our units in the field working.
Allen
Alfalfa Conference a big success.
January 17, 2010
We are home, a bit road sore, but had a great conference in Kennewick, WA. No sales, but several that are putting the PERC units in their spring budgets as well as a couple of custom operators that are starting gopher control businesses in Washington.
Very interesting comment by a custom operator in Eastern Oregon. "The custom gopher business is what is paying the bills!" Like many businesses as well as farming, he was severely stretched to pay his bills. The gopher control business he set up last fall has brought in the cash that keeps their operation afloat.
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