Designing a drenching gun
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  1. #1
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    Default Designing a drenching gun

    I hope I can express myself clearly on what I am wanting to build and hope its in the correct forum.

    I would like to build a hand held chemical drenching gun that will squirt out liquid around the stem of a plant. The amount of liquid needs to be calibrated to a predetermined amount per plant ranging from 5-12mls per plant.

    I had used an automatic livestock vaccination syringe back in the 90's but they were expensive and required a lot of maintenance, esp. the rubber seals on the plunger and valves. The employees' hands and wrists also suffered from fatigue a couple hours into the shift. Carpal tunnel syndrome comes to mind. I have thought of purchasing a bunch from China as priced quiet reasonable now, $4-$12 ea, but cant get around the the CTS.

    Basically wanting to make something similar and simple by using a battery operated metering pump or controller. The regular battery operated garden/ agricultural knapsack sprayers would be the perfect product but the pumps on these sprayers are high volume 1-2 lts/min and way too much pressure. Got thinking maybe a facet type fuel pump or something smaller with some sort of controller to cycle the pump to give the desired volume of liquid at the push of a button. A stepper motor on the pump with some sort of controller?

    I have been chatting to some folks on Alibaba but they just want to sell me whatever pump they have got and don't grasp the idea of what I am looking for.

    Another idea was some form of a peristaltic pump, but that seems too cumbersome and complicated to make.

    Appreciate your input as always.

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    What are those bottle mounted dispensers used at the tavern ?

    Scale one of those up maybe.

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    Why not just use a dosing pump? They are available with all sorts of chimical resistant seals.
    Last edited by slnielsen; 01-04-2020 at 01:04 AM.

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    Is this for fertilization or pesticide? Human exposure safety issues? Amount of total fluid carried, duration of use in a day?

    More information would help, as would pictures and ideally a video of how it's done currently (method you described). With more info we can try to help.

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    In central ca the ag business is king and things like this would be easy there if actual need.

    The university's my be working on something.

    We have not seen nor observed something like this but common farm size in thousands of acres the dispensing of materials is done differently.

    Exactly what are you trying to do?

    Fertilizer is commonly mixed with water as fertigation and other tasks already developed.

    Explain exactly what or why you are doing this task and we may be able to better help you.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

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    "The regular battery operated garden/ agricultural knapsack sprayers would be the perfect product but the pumps on these sprayers are high volume 1-2 lts/min and way too much pressure."

    If this would in fact be the perfect product then I would modify one for your needs. You could add a tube to the end of the hose and mount an small orifice with the hole at a right angle to the tube. This would lower the volume and cause the product to just dribble out the end. The issue you would have then is the delivery rate. If you don't require a lot of precision then you could squeeze the trigger for X amount of seconds to deliver what you need.

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    Morning,
    Thank you, had no idea there was such a thing so have looked. There are a couple of battery operated units but still delivering to higher a volume. Have found a small battery operated peristaltic pump so maybe this might work with a controller.

    Kamoer Kcm-odm Mini Dosing Chemical Metering Pumps Peristaltic Pump Price - Buy Liquid Dosing Pump,Chemical Metering Pumps,Mini Peristaltic Pump Product on Alibaba.com

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    have a poke around here on this site

    SMART Digital S and XL | Grundfos

    They come with controllers already.

    ditch that chinese rubbish.

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    How about those units used to serve drinks. Push different buttons for different drinks and I suppose the amount is preset and adjustable per push. What about pumps that mix epoxy to set ratios.
    Bill D.

    On edit. How about the powered vacination guns.

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    Quote Originally Posted by Milland View Post
    Is this for fertilization or pesticide? Human exposure safety issues? Amount of total fluid carried, duration of use in a day?

    More information would help, as would pictures and ideally a video of how it's done currently (method you described). With more info we can try to help.
    Ok, so part of tobacco culture, once the plant reaches the desired leaf number we break off the top excess leaves, bud, flower manually, called topping. The plant then pushes out suckers like in a tomato plant from the leaf axils. In tobacco we don't want this as it reduces the yield. At time of topping we use a 5ml cup of "suckeride", (a contact fatty alcohol,) which works on contact and burns the tiny suckers. Need to be careful at this stage to not burn the small top leaves of the plant with the chemical. Productivity is low, about 1800-2500 plants per person on an 8hr day with 15200 plants per ha (6150 per acre) The plant after 10 or so days again will try to push more suckers out, and we apply suckeride again. In the mean time the topped leaves have grown out and suckeride will be applied to these axils as previously these leaves where too small to get suckeride.

    The employee has a chemical cup with an extended handle and they dip the cup into the container of chemical hanging from their neck. Often the cup drips chemical onto the leaves which will make burn marks and eventually lead to bacterial disease into the top leaves. The top 6-7 leaves of the plant produce 75% of the crops' yield. Clean cured leaf pays the most. Another draw back of this hand application is that when cupped on, suckeride doesn't hit all the plant's leaf axils on the way down and suckers grow from the missed axils, which requires another operation a week later to remove suckers by hand if larger than 10-15mm as the suckeride wont control larger suckers and reapply the chemical.

    The applicator nozzle I am trying to design is circular with tiny nozzles, about 3-4 or 4-5, that will be lowered over the topped bud to the next open leaf and a squirt of suckeride applied to the stem, improving the ability of the chemical to hit each leaf axil as the axils are in a spiral going down.

    By having an electronic push button on the handle to control the pump and volume of chemical, the employee can push it once applicator is in correct position on the plant. thinking will take maybe 5-7 secs per plant. The key is to getting the suckeride all around the stem and often the employees miss axils and only apply 1-2 axils vs. 3-4 which is also time consuming. Having a sealed back pack of 10-15lts will eliminate spills and house the electronics, pump and battery.

    I have tried to adapt one of my battery operated sprayers but the pumps are too strong and were designed to spray continuously with short periods of cut off time before too much back pressure and bursting of pipes. Unless there is a way to turn the speed of the motor down. Possibly adding a pressure switch to cut out the motor once lines are pressurized, sealing off some part of the pump impeller? will take one apart to see how it was made.

    Photos and video to follow....

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    Did you try looking for drenching Guns?
    Used to medicate farm animals, some appear to be battery powered.
    We dosed hundreds of goats using these with a bottle of meds hung nearby feeding the guns.

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    I don’t know how you’d feed it or if the o rings could be changed to work,,,,, but wouldn’t a battery powered grease gun work??????

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    For such low flow I would forget the pump and use a pressure tank. maybe a co2 tank with regulator output into liquid tank to maintain constant pressure.
    A metered dose inhaler comes to mind. How do automatic bottle fillers measure the product going in?
    Bil lD

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    Overspray?

    Look up "microsprinkler"

    There are many different versions that have different spray type and matters depending on application

    Some spray 10 ft radius for tree root zone while others may fog.

    Looks like you could use a fine mist style on a wand along with a cup shield to protect leaves.

    The spray emitter regulates flow rate and there are many spray pumps that are adjustable from 20 to 100 psi at 12 vdc.

    The wand can be a standard off shelf spray wand with end modified.

    Spray want has built in trigger and pump is pressure controlled so turn on power, place emmiter where chemical goes and pull trigger.

    All off the shelf parts, tractor supply has many ready to go.

    The spray head is where the magic is, that is where you get creative.

    Google netafin drip for a starting point.



    Sent from my SAMSUNG-SM-G930A using Tapatalk

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    Solo backpack sprayer
    ULINE - Shipping Boxes, Shipping Supplies, Packaging Materials, Packing Supplies

    a pressure backpack sprayer like this has a lever that you need only occasionally pump to pressurize the tank. This leaves you to design any sort of wand nozzle arrangement you can dream of.


    here is a battery operated one, but unless i am mistaken it uses the battery and motor to pressurize the tank just like the hand pumped units. not to pump the liquid directly.

    Agri Ease Lithium-Ion 4 Gallon Backpack Sprayer | 90.709.015


    A nice drenching gun with backpack tank. you could have a motorized cam/crank drive 3d printed and clamp it over this handle. that sounds like a fun project. Basically gut a small cordless drill or similar for the batteries and trigger parts and make a motor drive housing that squeezes the handle. This project is a good one for a GOOD "maker" person with a 3d printer.

    Phillips Auto Drench Gun - Premier1Supplies

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    Couple of decades or more back I saw a small dose system working rather like the old fashioned mechanical, cam operated, petrol pumps. Set the stroke of the operating lever/cam to determine the quantity. Delivery spring defines the pressure. As I recall it the intention was to combine a high pressure at the delivery end with a low pressure at the input.

    I imagine something functionally similar could be done with a rotating inlet / outlet valve unit on top of a peg in slot or similar drive to a diaphragm or similar short stroke pump having a single combined inlet / outlet port. Simple battery motor drive. When trigger pushed the system rotates to align the port with the input side and drives the pump down as it turns. Once the pump is at full stroke further rotation moves the port past the inlet hole and over the outlet hole. Pump drives up, either by spring or peg in slot, dispensing the contents as the valve assembly continues to rotate. Motor stops at the end of the cycle with both ports closed off.

    In principle the dispensing gubbins can be done with 3 plastic parts and, possibly, some seals. Make uber cheap to throw away when it leaks.

    Clive

    PS The RCV model aircraft engine works in an essentially similar manner. Albeit with a conventional piston and crank in more "engineered" construction. RCV

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    Just saw ad on tv for a home kitchen faucet. You tell it how many ounces, cups, teas spoons etc. and it spits out exactly that amount.
    Bil lD

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    Pressure tank operating a air powered syringe would give precise metering and you could use disposable syringes that could be replaced when the seals failed. A couple of directional flow valves will give precise flow control.

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    The pump on this sprayer is merely two tubes (one in each hand). Just figure out a sleeve to set the distance the sleeves can "stroke" to set your dispensing amount.

    Search for Indian Backpack Sprayer

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    Quote Originally Posted by CatMan View Post


    The pump on this sprayer is merely two tubes (one in each hand). Just figure out a sleeve to set the distance the sleeves can "stroke" to set your dispensing amount.

    Search for Indian Backpack Sprayer
    I believe such spray pumps are called "trombone" sprayers. You can sleeve it down for your tiny flow rates.
    Bill D


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