How does this Chinese device for catching locusts work?
December 3, 2020 3:02 AM   Subscribe

Here is the patent. The original text is in Chinese and English text is available through automated translation. Could a good speaker of Chinese with some engineering background tell me how this thing is supposed to work?

Context: there's a locust plague going on in Eastern Africa and I'm co-writing a paper about locust-catching methods. It turns out that there are lots of Chinese and Russian patents for such devices (which were pioneered by the US in the 1870s), but they're all in their original language with no proper English translation. I've been able to more or less figure out most of them (they're basically big vacuum cleaners) but I don't get how this one works, except that it has nets on each side, can be mounted on a motorcycle, and the Bernoulli principle is involved. It does not seem to require a power source, but I'd like to be sure of that.
posted by elgilito to Technology (6 answers total) 4 users marked this as a favorite
*I just looked at the abstract* My Chinese is pretty rusty so someone else might be able to offer something more accurate, most of the text is technical details about its construction. The part about the functioning I translated as "after the travel mechanism(??) is disturbed, the hopping locust that's within the scope of the frame is sucked into the net, thus capturing the it. "
posted by Res0ndf7 at 1:08 PM on December 3, 2020

Glancing over the details I think theres some sort of flap or something that when a bug hits it falls back and the bug then gets caught in the net. Sorry if i missed the mark, no engineering background here. The two squares labeled 1 and 2 are what the bugs hit, maybe there is nets attached to the back of them.
posted by Res0ndf7 at 1:14 PM on December 3, 2020

I don’t understand (much) Chinese, but I had a look at it anyway via both versions of the machine translation, and as far as I can see, there’s very limited information on how the device actually goes about catching locusts, as most of it seems to describe the construction.

It seems to be fairly clearly stated that it itself doesn’t need a power source (but should be mounted on a motorbike). The idea seems to be that the locusts are disturbed by the motorbike and they hop into the air and are then sucked into the net. They talk about an airflow channel between the catching frame and the net - so that the flow of air is restricted in some way, so it has a higher velocity. This is where the Bernoulli principle is involved - increasing the velocity means that the pressure goes down and a slight vacuum is produced to suck the locusts into the net.

I have to admit, despite reading it several times, and looking at the drawings, I still don’t have a clear understanding of how that airflow restriction takes place (or how the whole thing works concretely!) I’m not sure how much of that is the translation vs. patent speak vs. me just not understanding vs. it won’t actually work.

As an aside, it’s a utility model rather than a patent. From what I’ve understood from our IP lawyers, that means that there is little or no checking of the application before it is “granted”, only a check that the proper application process has been used. Unlike an actual patent, it won’t have been looked at by a patent examiner.
posted by scorbet at 1:42 AM on December 4, 2020 [1 favorite]

Best answer: The basic operation is clear enough. The device mounts on the seat of a motorcycle. When the motorcycle moves the locusts are disturbed and jump up. On both the left and right side of the motorcycle is a baffle and then below the baffle a net. So the Iocusts jump up and are either sucked into the net or they hit the baffle and sort of bounce into the net.

The other main feature is the net and the baffle are attached via a kind of a spring device so if they encounter an obstacle they just spring up and then spring back down into place.

Also a radio is attached, presumably so that a leader and different motorcycle units can coordinate.

In short, you're driving a motorcycle around scooping up locusts into nets on each side. The device just positions nets in the best location for catching the locusts, has a baffle to help direct the locusts into the net, allows you to position the nets up/down and left/right a little bit to find the best position, and has a spring so that the nets bend up and back rather than just breaking off when an obstacle is encountered.

Here is the most helpful bit of the description:
In the working process of a locust trap of the utility model, when specifically used:
The locust trap is installed and connected to the back seat of a walking device such as a motorcycle. First, adjust the position of the locust trap. The left locust trap frame 1 and the right locust trap frame 2 are positioned axially by the shaft clamp 3, and the left locust trap frame 1, right The locust trapping frame 2 can adjust the axial distance on the left support shaft 4 and the right support shaft 7 within the range of 0~500mm. The vertical angle of the left locust trapping frame 1 and the right locust trapping frame 2 can also be automatically reset by the capture frame. 5 Adjust. When encountering a local obstacle on the ground, the left locust trapping frame 1 and the right locust trapping frame 2 are forced to rotate around the axis. After leaving the obstacle, they will return to their position under the action of the spring 502 to achieve the effect of automatic obstacle avoidance.
posted by flug at 9:51 AM on December 4, 2020 [1 favorite]

This drawing shows the missing piece not shown in any of the other drawings – the giant net that actually catches the locusts. Apparently there is one net mounted on each side of the motorcycle.

The baffles are mounted just above each net and are at a slight angle to help direct the air and the locusts into the net.
posted by flug at 9:57 AM on December 4, 2020 [1 favorite]

Response by poster: Thanks for the answers. For some reason, many of those patents/utility models do not include clear drawings and the texts are somehow obfuscated, but the image of the locust catcher driving around "scooping up locusts into nets on each side" was useful.
posted by elgilito at 9:29 AM on December 11, 2020

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