Pneumatic Insect Collection Device
See the Prototype in Action in this video.
This is log of the development of an insect collection device developed for California Polytechnic Universities (Cal Poly) College of Agriculture under the guidance of the Cal Poly Appropriate Technology Research and Development Group.
The primary goal of this project is develop a device that is capable of collecting bugs using an air blower powered by a battery which can, in turn, be charged by a solar panel. Two secondary goals are: 1) that the device be capable of collecting a sample of insects from a variety of plant types that is representative of the insect population of those plants and 2) that the device be capable of collecting a large enough percentage of insects from plants so that it might be applied as a method of pest abatement.
Current State of Project Update
The prototype is now powered by an 18V lithium polymer battery that is much lighter,
smaller in size, and of greater charge capacity than the previous battery. A removable battery compartment made of fiber-glass composite is affixed to the main-tube with adhesive backed hook and loop; theis houses the power switch and battery. The estimated run-time of the new battery is about 20 minutes though further testing is required to establish whether this is the case or not. An unexpected result of increasing voltage supplied to the motor was that the increased fan speed caused the fan blades to stretch out slightly and contact the cylinder wall. This problem was solved by removing material from the cylinder in the areas where conflict was occurring. The fan is fully functional though it tests should be designed to ensure the device will safely operate at the higher voltage before anyone is allowed to operate the device.
Some design considerations have changed since the last update, the current prototype is to be carried by hand only and with no components mounted
to a backpack. This change was made in order to see if we might come up with a design that more closely matches RVI’s D-Vac operation, while improving upon its usability and function.
|Perma-Cool 3300 CFM|
We have kept the same “fan on a tube” design as we used for the previous prototype due to the ease of manufacture and because it closely resembles the D-Vac form. This time though we opted to make the cylinder out of a fiber-glass composite to reduce weight and add rigidity. Greater rigidity is necessary on this prototype because we have also added a larger, more powerful blower. We again decided to use a Perma-Cool blower as it is capable of moving more air than any other pre-made direct current fan of its size (12in diameter). To power the fan, we first thought to use another sealed lead acid (SLA) battery like the one used to power the first prototype. We found that having the SLA battery mounted to the fan tube made it heavy and tiring to wield, so we went with a lithium polymer battery instead. The new battery, while being smaller in size and lighter in weight, also has a much greater charge capacity.
The blower, fiberglass cylinder, bug capture net, carry handles, and blower safety backing are all made and assembled but we are waiting on specific battery connectors to arrive in the mail to make the device completely operational.
Using the SLA battery, the prototype was tested in the Cal Poly Student Experimental Farm where it successfully captured a wide variety of bugs from a diverse selection of vegetation.
Construction of a new version of our fan on a tube bug vacuum began today as we began making a new tube out of fiberglass. We are using fiberglass because we can create a tube that is rigid enough to mount our fan to that is also light-weight. We intend to mount the fan tube to a backpack that will also carry the batteries. The fan tube will then be reduced down to where a flexible duct will connect it and a collection cone that will house net.
We will then test the apparatus for effectiveness at collecting insects of various forms of plants.
|Ron Holding the D-Vac|
We met with Ron of Rincon-Vitova Insectaries (RVI) today in Monterey where he talked to us about the the current and past bug vacuum products that RVI had developed. Many of the contraptions he show us used squirrel cage blowers as the driver of air – some powered by gas engines and some by electric motors. The D-Vac is now the only bug vacuum that RVI sells and is intended for bug sampling.
Notably, our fan on a tube pulled nearly the same volume of air per second as did RVI’s D-Vac when we tested both with our anemometer. When we showed our device to Ron he was interested in what we had come up with. We took both the D-Vac and fan tube out to RVI’s garden and used both to sample the bugs there. Something we noted about the D-Vac and it’s two-stroke engine powered blower is that it was more capable of pulling air through a reduced opening at a higher velocity than our fan tube. This seemed to give it more versitility as Ron demonstrated using different reducers to sample different types of plants and trees.
Today we put together our prototype Bug Sucker core which is composed of the new Perma-Cool fan, a 3’x3′ sheet of aluminum rolled into a cylinder, and duct tape. The assembled core was connected to a car battery and performed as well as we had hoped – moving significantly more air than
the commercial vacuum cleaners we tried. Tomorrow we will take the core to the physics lab to take
measurements of its power consumption and to test the fan’s behavior under various conditions.
The plan going forward is tentatively:
- Measure power consumption and intake air velocity
- Decide on a battery and method of carry
- Test prototype core on various plants
- Design second core based on what we learn
Currently, Brent is working on drafting our design in AutoCAD
Mike was able to get in contact with the people who make the D-Vac, a bug vacuum already in
existence. They said they are interested in collaborating and possibly meeting with us in Monterey,
where they are based.
Experiments with existing commercially available vacuum cleaners has made evident that our bug sucker must move significantly more air than your average workshop vacuum. This has led us to search for an electric blower that moves the greatest volume of air possible that is also a size convenient to carry on one’s back. Presently, we have ordered an after market automotive radiator fan due to it’s great air moving capabilities and low cost.
Moves 2350 cubic feet per minute
Draws 4.7 amps at 12 volts
Fan diameter is 10 inches
Shroud dimensions 11x10x2.25 inches
The intention now is to construct our own vacuum machine according to the basic design below – we will have to wait to execute until the fan arrives: scheduled for Wednesday 06/29/2016
|Bug Sucker Core|
Persons Actively Involved
Brian Park ————— ME Student
Thomas Headland —– ME Student
Eltahry Elghandour —– Mechanical Engineering Advisor
Pete Schwartz ———– Physics Advisor
Ashraf Tubeileh ———- Horticulture and Crops Science
Ron Whitehurst ———- Rincon-Vitova Insectaries
Persons Previously Involved
Mike Stromecki ——— Aero Student
Brent Taylor————– BRAI Student
|Pete Schwartz inspects the first haul of insects during prototype demo.|