Introduction: Versatile Liquid Dispenser

This liquid dispenser is a cheap improvement for everyday life, from parties to camping! This design consists of a small air pump and a faucet like structure, meaning you only need to pump, turn the handle to open the valve, and place your cup underneath. Using it can save mess from people accidentally spilling their drink all over the floor when pouring, and is more enjoyable, especially for younger children. This can also be used in camping conditions, where you may not want to travel all the way to the restroom. You can just pump up the bottle, open the valve, and water will come out at just the right speed. The materials used are pretty cheap, and can be bought from most hardware, craft, or party stores. Buying the supplies for these in bulk is more cost effective, as most supplies used are commonly bought is large quantities, such as PVC, where you only need about 4 inches of.

Step 1: Gather Supplies

For this project, you will need the following:

- 1x Balloon animal pump (or some other small equivalent)

- 1x 1/2 in. PVC T-Joint

- 1x 1/2 in. PVC L-Joint

- ~4 in. of PVC, cut into a 1.5 in. piece and a 2.5 in. piece

- 1x Popsicle stick

- ~12 in. or 1/4 rubber tubing (food safe tubing is a good idea if you are planning on using this as a beverage dispenser)

- 2x bendy straws/normal straws (more tubing also works, as long as it reaches the bottom)

- 1x Sprinkler plumbing valve

- 1x Sprinkler plumbing I-Joint

- 2x Sprinkler plumbing L-Joint (The above three can usually be bought together in a variety pack)

- Liquid container

- 1x bottle cap that fits on the container (must be relatively airtight)

- Hot glue (Duh!)

You will also want to have the following tools on hand:

- Drill (with 1/16 (or similar), 3/16 and 7/32 drill bits)

- Scissors

- Sandpaper

- Pliers

- Saw (for cutting PVC to length)

- Hot glue gun (Duh again!)

Step 2: Prepare Materials for Assembly

Before adding parts together, it is best to modify the parts first

For the T-Joint: Drill roughly a 3/16 in. hole as shown in the picture. Using a smaller bit, such as a 1/16 in., will help the drill to not slide when drilling the larger hole. This hole will be used for air flow. Depending on your pump, this may not be necessary. Sanding the ends of the joint will help with adhesion of the glue.

For the bottle cap: Drill two holes on opposite sides of the cap as show, these should be about 7/32, slightly less than the diameter of the tubing you are using, as this will provide an adequate seal. Sanding down the top of the bottle cap will also help adhesion with the hot glue.

For the 2.5 in. PVC: Using scissors or a similar cutting tool, cut a hole as show going through about half the length of PVC. The goal here is to have a slot in which you can slide the valve into as shown in the next step.

For the popsicle stick: Simply cut in half.

Step 3: Insert Valve

For this step you must insert the valve into the notch you cut in the 2.5 in. length of PVC shown in the last step. This can be tricky, depending on which valve you use. Make sure the valve is able to open and close freely and there are no leaks.

Step 4: Add Tubes to Bottle Cap

Connect one of the L-Joints to 2-3 in. of the rubber tubing and insert into on of the holes in the cap. It should be a little difficult to fit the tubing through the smaller hole (this means it will resist air leaks). This tube will be transporting liquids up and out of the container. Insert 3-4 in of the tubing into the other hole, with most of it sticking out the top. This tube will be connected directly to the air pump.

Optional: Add a little bit of hot glue to the center top of the cap, especially around the sides of the hole, as this will improve the seal. Avoid the edges, as pieces will need to be attached later.

Step 5: Readying the Output Tube

First, make a small circle of glue around the outside of about 2 in. of tubing near one of the ends. Repeat this a few times, to get a size large enough to fit in the other 1.5 in. piece of PVC. You will then add a copious amount of glue into the PVC tube, 1/2 - 1 in. deep.

Step 6: Securing the Valve

Take the valve out of the 2.5 in. of PVC. Attach 2-3 in. of tubing on one end. Re-insert the valve, where the tube is coming out of the un-cut end. Add some glue to the valve so that is doesn't come out.

Step 7: Connecting the Faucet Assembly

Trim the output tube on its longer side and attach a sprinkler L-Joint as shown in the top right image. Next, add 1-1.5 in. of tubing to the sprinkler L-Joint and insert the 1.5 in. PVC tube into the PVC L-Joint as shown in the middle right picture. Connect the valve to the rubber tube sticking out the PVC L-Joint (this part is tricky) as shown in the bottom right image. Connect the 2.5 in. PVC tube to the PVC L-Joint as shown in the top left image (use hot glue if needed because the cut in the pipe will decrease the connection strength between it and the L-Joint).

Step 8: Connect T-Joint and Bottle Cap

Feed the tubes connected through the bottle cap through the PVC T-Joint. connect the tubing coming off the valve to the L-Joint in the PVC T-Joint through the bottom of the "T" shape, as shown on the left image. You may need to pull more tube through the cap to help all connections fit, which will also make it easier to tell air and liquid tubes apart. Insert the 2.5 in. PVC tube into the base of the PVC T-Joint, and glue the bottle cap onto another side of the Joint, as shown in the image on the right.

Step 9: Finishing Touches

Add a little hot glue to the underside of the cap, making sure it DOES NOT interfere with the threads. You don't want to ruin the seal. Connect the I-Joint to the longer bit of tubing, as this will allow you can connect and remove the final liquid tube. Connect the pump to the tube coming out of the open end of the PVC T-Joint. You can sand down the part of the pump where you will be attaching it to the T-Joint for a better connection. Glue the pump to the T-Joint. Make sure the valve is in the on position, and glue the two pieces of popiscle stick to each other and then the valve in the position you want to call open.

Step 10: Preparing for Use

Use your tubing or straws to make a tube that can reach from the head of the container to the base. This will be the tube that pulls up the water, so make sure that it does not have any leaks. When you are ready to use the pump, connect the tube or straw to the I-Joint, fill you container, and screw on the entire assembly.

Step 11: Explanation of Physics

The mechanism behind this build is quite interesting. The pump provides air from the atmosphere into the sealed bottle meaning that the density of air in the bottle increases and therefore so does the pressure. Since the only output to release the pressure is the tube at the bottom of the bottle, the pressure forces the liquid up and out the faucet until pressure evens out again inside the bottle. Opening and closing the valve determines the liquid's ability to escape; if it is closed, the pressure cannot decrease and the liquid does not move, but if it is open, the liquid is allowed to escape.

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