The simplest answer to this question is that you have to make the inlet valve of the compressor finer to make sure that it sucks air efficiently. For that, you can install any sort of metal extension at the very beginning of the inlet valve.
What Is the Difference Between an Air Compressor and a Vacuum Pump?
In a vacuum pump, the efficiency is higher. As the pump takes input from a relatively closed environment, high pressure is not necessary. The pump can suck air from that kind of environment and make the setup air-free.
On the flip side, the air compressors are used in an open environment. An air compressor has to intake air from the free atmosphere and then compress it to store air inside the tank.
Air compressors can also be used instead of vacuum pumps. But it’s necessary to make sure that air is sucked in a controlled manner. For that, you have to install a metal pipe with a smaller diameter at the intake. This can be done with additional covering surrounding the pipe inlet or directly installing a hose barb.
How to Make a Vacuum Pump With an Air Compressor?
Though air compressors are meant to deal with primary gases, they are used in various applications. It’s probably not a surprise that there are different types of air compressors. However, refrigerator compressors and Tire Inflator-type Air Compressors are used to create vacuum pumps.
A. How to Make a Vacuum Pump From a Refrigerator Compressor?
A compressor inside the refrigerator acts like a ‘pump’ by sucking refrigerant from the condenser and then pass it forward. To convert this type of compressor into a working vacuum pump, we have to follow these steps:
1. choosing a proper base & prepare it
As the compressor is designed to sit inside (backside) of the refrigerator, it doesn’t have any dedicated base of its own, rather it uses the slots that are pre-made in the body frame of the refrigerator.
But when you are using it as a separate pump, it needs something as a base. Moreover, the joints between the two planes have to secure enough to withstand the vibration.
1.1. Choose a square wooden board as the base support structure.
1.2. Make four holes by drilling at four different corners of the support.
1.3 Make additional holes in the pressure gauge.
1.4. If you want to make the setup portable, in this stage, it’s better to make slots for the handlebar.
1.5. Additional supports can be placed underneath the base. It will prevent wobbling.
1.6. Protective coating can be applied at this stage depending on the situation of the base.
1.7. After the coating is dry enough, you can place the compressor and secure it with screws. It’s necessary to use washers between the nuts and bolts to secure the joint.
1.8. Similarly, install the handlebar.
2. Install the circuitry
In general, the compressors are powered by AC voltage that runs through adjacent circuitries of the compressor. These include a capacitor, relay, and additional wirings.
The wiring part, that’s why vary in different compressors. Most manufacturers tend to print the circuit diagram on the body of the compressor. That diagram can be used as a reference. If that’s not the option, you can see the user’s manual provided by the manufacturer.
3. Modify the inlet
As we’ve discussed, a sort of metal extension is needed to make the input airtight. In this case, we can use a metal pipe. A steel jar cover can act as an airtight seal.
First, make a hole at the center of the cover and then pass the metal pipe through it. Connect the other end of the pipe with a PVC pipe by installing proper sealing. Then connect the other end of the PVC pipe with the compressor intake. Here, a sealing tape can be a good companion for making these joints airtight.
4. Block the output
Unlike the refrigerant, the air needs not to go elsewhere through the compressor. So, the discharge point should be blocked. It will prevent any surrounding atmospheric pressure to rush in. for this, you can use a hollow tennis ball (with a hole for connecting the outlet pipe) or a piece of foam.
5. Test the setup
5.1. Start the compressor and check for any spark
5.2. Check for any leak at the intake points.
5.3. Make sure that the wobbling for the vibration is minimized.
B. Convert a Tire Inflator-Type Air Compressor Into a Vacuum Pump
Tire inflator type compressor has a great ability to suck air and so it can also be converted into a vacuum pump very efficiently. You need:
1. Braided PVC tube (1/4-inch of diameter inside)
2. Hose barb (for ¼-inch tube)
3. Epoxy glue
Follow these steps to get started:
1. Open the casing and locate the air intake
Opening the case is relatively an easy task. Usually, several screws hold together the two parts of the casing. Remove those screws by using a screwdriver and apply a little bit of force to divide the casing.
2. Hose Fitting installation
After opening the casing, you can see the pump assembly. Flip that assembly and there you can find the cylinder. At the face of the cylinder, the air intakes should be located. In most cases, these are smaller holes. In some cases, there are barb fittings that connect with mufflers.
If you find such assembly with the muffler, just insert the PVC pipe directly and it’s done! If you cannot find that you have to connect an external barb. It must be rated for use with a ¼-inch diameter pipe. Glue down the barb into position.
3. Prepare the intake
Remove the dust from the surrounding surface and apply epoxy glue to form a wall around the holes. Connect the barb onto the glued surface and let the epoxy get dry, wait about an hour.
4. Fit the hose and modify the casing
Simply put the hose into position and it will automatically be attached. Then cut a properly sized slot at the casing to run allow the pipe to run through it. At last, fix the cover.
Q: Can I run a refrigerator compressor without a capacitor?
Ans: When you are using it with a refrigerator, removing the capacitor may cause the PTC system to fail. But as you are running the compressor as a pump, in this case, the compressor will start without the run capacitor. But over time it will be difficult to start it.
Q: Is it enough to use a tire inflator type compressor as a vacuum pump for lamination?
Ans: Of course! The suction power of such a DIY pump is enough for using it for lamination purposes.
Making a vacuum pump with an air compressor is not a big deal if you know how vacuum works. But you need to take proper safety measurements, especially while drilling and cutting. It’s better to wear gloves in these situations.