Everything about Vacuum Pump – BACO ENGINEERING

Content

1 BACOENG Vacuum Pumps

2 Vacuum and Ultimate Vacuum

3 So, what is the right type of vacuum pump?

Pump-down test

4 BACOENG Vacuum Pump compared with Other Brands

5 Different Applications, Different Pumps

Typical application and recommended model

6 Recommended videos from Youtube.com

7 Common problems and Solutions(FAQs)

8 What should I do while failure occurs?

9 Parts & Fittings Link for Vacuum Series

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BACOENG Vacuum Pumps

BACOENG is offering a number of vacuum pumps for a variety of purposes, especially for maintaining air conditioning units in cars or for stationary units, in manufacturing for degassing or mechanical manipulation, and other interesting applications.

Vacuum and Ultimate Vacuum

In our normal environment the air pressure is around 100,000 Pascal or 760 millimeter of mercury column. Let’s look into a closed vessel like a steel tank with a pipe and a valve connected to it. As long as the valve is open, the chamber has the same pressure as the normal environment, since it is open to the atmosphere. If a pump is attached to the pipe then gas (like air from the atmosphere) can be either forced into the vessel, which creates a positive pressure or over-pressure, or it can be forced out of the vessel, which creates a negative pressure or vacuum. In both cases the relative pressure (positive or negative) is displayed in comparison to the outer atmosphere.

Normal vacuum pressure gauges show relative pressure. Therefore any measurements are dependent on the atmospheric pressure, which is dependent on height above sea level and air conditions. Let’s say we have a certain vacuum at sea level and the gauge shows -0.095 MPa. At 900 m or 2950 ft height above sea level the same vacuum gives -0.085 MPa on the gauge, although the vacuum quality in the two situations is exactly the same.

Hence, for a good measurement a number of outer parameters need to be carefully considered or artificially kept constant. Additionally, the vacuum tank, pipes, pump, and the gas fed into the pump need to be perfectly dry. Any leaks need to be significantly smaller than the pumps ultimate vacuum. Because these difficulties comparing pumps with a simple measuring setup is hard.

Depending on the application, a weak vacuum can be sufficient or an extreme vacuum may be required. I.e. for holding material in place by a vacuum chuck the vacuum does not need to be perfect, but the gas leaking into the suction cup needs to be removed fast enough. For other applications, like removing the air from an electron tube or a vacuum chamber of a scientific device the vacuum quality needs to be better by magnitudes but required quantity may be tiny.

Aside of the quality also the quantity of gas pumped, measured in cubic feet per minute (CFM) is important to consider. For a water pump it is a simple task to figure the time required to empty a vessel, but pumping gas is different. For an example let’s look at a tank of 6 cubic feet volume and a pump with 3 CFM.

If the vacuum pump removes half of the volume, then at the same time the gas remaining inside expands and takes up just the same volume again, although at half the pressure. If you empty out half of that again, the same thing happens, now reaching a quarter of the original pressure, and so on. In result, the pressure in the tank is converging zero, but never reaching it.

The geometric displacement (“free air displacement”) of the pump stays the same all the time, but with decreasing gas density the mass flow decreases steadily. After some time of pumping you reach ultimate vacuum, which is the pressure that the pump can reach at best, because the air from the outside forces in with the same strength as the pump is moving it out again.

If the vessel and pipes to be evacuated are very well sealed – that is especially the connectors in between them – then, up to the point of ultimate vacuum, the CFM rating is only effecting the time needed to decrease the pressure down to a desired point. For less well sealed applications like a vacuum chuck with a much higher leak rate the CFM rating may decide on success or fail.

Guessing leak rates is not easy, but for sure it is recommendable to take a pump with an ultimate vacuum being quite a bit better (that is lower!) than the required vacuum, because otherwise you get into the flat end of the curve shown above, where it takes very long to reach the required vacuum and small unexpected leaks possibly make you fail at all.

So, what is the right type of vacuum pump?

There are very different types of vacuum pumps available for different purposes, but affordable and most suitable for a wide variety of uses are rotary vane pumps. With a pump of that type you can reach around 1 Pa or 7.5 Microns, that is 1/1000 Percent of normal atmospheric pressure. For even better vacuum the core piece of the pump is doubled up, so that the first stage creates a pressure of around 1 Pa for the second stage, which then can get down to around 0.01 Pa or 0.075 Microns of ultimate pressure.

BACOENG is offering a variety of single stage pumps as well as double stage pumps listed in the table below.

The ultimate pressure ratings for the single stage pumps are great and excellent for the double stage pumps. The different models and motors provided by BACOENG allow a well matching selection for the intended CFM rating and vacuum quality.

Pump-down test

BACOENG did a series of time measurements for pumping down a 5 gallon vacuum chamber. In a diagram of pressure over time the theoretical curves and measurings show up like in this diagram:

Due to the nature of gas pressure there is always a very flat end of the curves towards the right. Somewhere in that right end the ultimate pressure was reached, but this type of diagram does not allow a good decision whether the pumps do well or not.

This changes dramatically if the pressure axis is displayed in logarithmic scale, as shown in the next diagram. Due to the logarithmic axis all the curves now appear as straight lines and show clearly the values that can be expected at the theoretical optimum. The measurements of all tested pumps except for the Mini 3CFM are closely matching the theoretical maximum, demonstrating an accurate construction and manufacturing without significant internal losses within the pump.

For the MINI 3CFM the motor power is the limiting factor. The MINI 3CFM still reaches its ultimate pressure, but it takes longer and is less efficient due to the reduced motor power. That is a backdraft, but the pump has its benefits in regard to size and weight if you look for something perfectly transportable.

In addition to the conventional rotary vane pumps BACOENG is now also offering an oil-free pump. Oil-free is a useful technology primarily in two respects: If there is no oil as sealant and lubricant in the pump, then no oil can be contaminated when pumping vacuum from a setup where water or solvents may be exhausted with the gas to be evacuated, i.e. for running a distillation on a rotary evaporator. Also the pump does not need an oil separator / exhaust.

For several industrial processes oil is undesired in the production process, i.e. for food processing, in the pharmaceutical industry, and for handling clean products. Because rotary vane pumps always have a slight loss on vacuum oil in their exhaust they are not usable in such cases.

If the gas stream to be evacuated carries water or substances that are accumulating in the vacuum oil and destroying its properties, an oil-free vacuum pump is the way to go as well.

These pumps are designed in a different way than rotary vane pumps and require a high degree of manufacturing accuracy. Therefore the price is usually 'industrial' as well.

BACOENG Vacuum Pump compared with Other Brands

Two typical competitor models show the advantages of BACOENG pumps:

While Brand-R delivers the highest free air displacement it is also the highest in price. In opposition, Brand-X delivers a lower ultimate vacuum as well as free air displacement. This lower priced model is technically as well as from the viewpoint of design inferiour to the BACOENG model.

For low vacuum requirements and when time is not important you may want to choose Brand-X. If you seek for a good performance at a competitive price it is recommended to go with BACOENG.

The BACOENG single-stage vacuum pumps show a great ultimate vacuum. They include an oil separator to minimize smell and loss of oil. You do not have to deal with distributors and separate gauge instruments right on top of the tank because the pumps already come with it!

The design is kept in the traditional orange / silver look of BACOENG. The body of the pump is well shaped and the heat fins going across the oil tank and motor give the unit a neat and compact appearance. The pumps come in 110 V and 220 V for all available versions to allow usage with either power systems.

The BACOENG double-stage vacuum pumps deliver an ultimate vacuum of up to 0.01 Pa / 0.075 Microns and are pumping down in almost the minimum time calculated by the gas theory. Depending on the model you can get up to 10 CFM free air displacement, outnumbering many competitors for portable vacuum pumps.

The pumps are delivered with an efficient oil mist separator and a vacuum gauge. The body of the pump is well shaped and the heat fins going across the oil tank and motor give the unit a neat and compact appearance. The pumps come in 110 V and 220 V for all available versions to allow usage with either power systems.

Different Applications, Different Pumps

The MINI BA-1A is a nice and light-weighted pump, that will fit in the tool box and not add to much weight. The smaller motor is the main reason for the reduced weight, but also increases the pumping time if you have to deal with larger systems. An oil exchange is easy and low in price due to only 150 ml for a full exchange. This pump will be good for car AC and small home AC systems and for occasional work in the shop.

The Standard BA-1 is probably the right pump for you, if you are basically happy with the CFM rating and pressure of the Mini but don’t want to give in on power. The motor is ¼ HP. Additionally due to the lower RPM of the rotor the noise development is smaller and the moving parts have presumably a longer life.

If you need a higher ultimate vacuum or a higher CFM rating then take a look at the Advanced 2BA-1.5.. It is a 2-stage pump with an ultimate vacuum of 0.01 Pa or 0.075 Microns and delivers 5 CFM free air displacement. Regarding the pump-down time the motor with ½ HP seems well dimensioned and the filling is still only 300 ml of oil. Additionally the pump comes with two different connectors, 1/4 SAE and 3/8 SAE, so that you don’t have to worry about adapters.

Check out the Prenium 2BA-4 if you need an even higher CFM rating and weight is not a problem. This beast brings 16 CFM and is also a 2-stage pump, but equipped with a ¾ HP motor. It comes with 2 SAE connectors, 1/4 SAE and 3/8 SAE, just like its smaller brother.

Now there is an oil-free vacuum pump available as well, the HL-40V. If you want to get rid of oil changes or if oil smell in the exhaust is undesired then this pump may be fitting to you.

Typical applications and recommended model

Vacuum pumps can be used to transfer gases or to make use of the air pressure surrounding us permanently. There are a wide variety of applications.

Filling AC units requires removal of the normal air and moisture within the piping and the compressor before refrigerant can be filled in. This is a classical application for vacuum pumps, no matter if for cars or stationary units. Vacuum is applied to remove as much as possible air from the system. At the same time the moisture evaporates at low pressure and is also exhausted from the system. If that is done, the refrigerant can be filled in through a specially designed valve system. The CFM-rating depends on the size of the AC system, so for maintenance on a car the MINI BA-1A will be well fitting, while for an entire house installation you might want to go with the Standard BA-1.

Some processes, like mold making with silicon or casting with epoxy resins requires the liquids to be as free of bubbles as possible. Unluckily the preparation of these liquids requires stirring, which introduces bubbles into the highly viscous liquids. It is not possible to let them just sit and wait for the bubbles to move out by means of gravity, because the chemicals would set in the meantime. Exposing the mixtures to vacuum allows the bubbles to grow to a multiple of their normal size, forming a foam. The foam is mechanically instable and by a repeated exposure to vacuum and normal pressure the bubbles burst and the trapped gas leaves the mixtures in a few minutes, resulting in clean molds or casts. For the amount of resin or silicon used normally you would like to go with the Standard BA-1 pump.

A similar application is the degassing of wine after maturing. It contains carbon dioxide that for some processes of wine making has to be removed from the wine. Stirring it with mechanical tools always contains the risk of unintentionally introducing harmful microorganisms that spoil the product. Some pressure changes from normal pressure to vacuum and back release the carbon dioxide from the wine without mechanical interference. The pressure should not be below the boiling point of alcohol, so the most important part is to have a gauge, which comes with all BACOENG pumps. The HL-40V oil-free pump would be the best fitting one, or you use a MINI BA-1A with an exhaust hose.

In mechanical manufacturing the usage of vacuum chucks is quite common now, as it allows to hold down objects without much manual labor. Large or fragile work pieces to be processed that have at least one flat side are placed on a plate with many small holes. The plate is attached to a vacuum pump. By removing the air from underneath the work piece a vacuum is formed and the air pressure is holding down the work piece during mechanical processing. For this kind of work you need a pump with a high CFM-rating, like the Standard BA-1 or even the Advanced 2BA-1.5.

In the same way vacuum is used for manipulation of sensible objects that shall not be touched during processing or for lifting gear, where objects can be lifted without the need of attaching hooks or ropes to them. The CFM-rating is usually quite low, so the MINI BA-1A or the Standard BA-1 fits usually for applications.

Air pressure is also indirectly used when wrapping products in plastic foil or for vacuum forming. For wrapping the object is enclosed in plastic foil. By vacuum unnecessary air is removed to reduce the package volume. Then the exhaust opening is closed by welding the plastic shut. The technology is used for weatherproof packaging of large machinery before shipping as well as for simple products like coffee. Depending on the size of enclosing bags select a pump with either smaller or larger CFM-rating. You do not need a very good vacuum. A single-stage pump like the Standard BA-1 will do the trick.

Forming is a different technique and facilitates a negative shape in a vacuum box with a flexible rubber top. Then i.e. a hot and flexible piece of plastic is put on top of the negative and the lid is closed and quickly evacuated. The flexible top is pressed down due to the vacuum building up underneath and presses the still flexible hot plastic against the negative shape, where it cools down and hardens. If you do not use a vacuum buffer (surge tank) then use the largest CFM-rating that you can get, like the Prenium 2BA-4.

Removing gas for impregnation or restoration of porous objects like wood allows to quickly transfer impregnating liquids into the thousands of small pores to alter properties, appearance, and resistance. The wood is put into an impregnating liquid, like wax or oil and placed into a vacuum chamber. Under vacuum, gas sitting in the pores expands and bubbles out. The vacuum is released and now liquid can enter into the pores and remains there. For smaller pieces of wood and an appropriate vacuum vessel you would like to go with the Standard BA-1 pump.

For scientific purposes a wide field of applications for vacuum exists. Vacuum pumps are used for distilling and separating liquids at low temperatures, to transfer liquids within equipment by suction, or to increase the speed of filtering. Surface modifying processes like plasma vapor deposition and sputtering would not be possible without vacuum. Vacuum also allows the creation of very clean environments. In vacuum particles can not float, they fall as fast as a feather in vacuum. Mostly the vacuum requirements are very high, so choose a pump from the Double series with a CFM-rating according to your application.

Recommended videos from Youtube.com

Choosing the right pump
https://www.youtube.com/watch?v=Q0Pj0A_dsdQ

If you want a quick yet good introduction on picking the right type and size of vacuum pump in respect to AC-maintenance you may want to spend 3 Minutes on:

Lab activities
https://www.youtube.com/watch?v=rCDznFHTMac

This is a nice introduction into vacuum pumps and some additional utilities useful for laboratory use.

How to Properly Recharge Your AC System
https://www.youtube.com/watch?v=Pdq8JAlct6s

Changing AC on a car is not explained in a sentence, but these 13 Minutes give a good instruction on how to do it!

Removing CO2 from matured wine using a vacuum pump
https://www.youtube.com/watch?v=Wdlt45LRBbY

This video describes how to remove carbon dioxide from matured wine without the need to use a mechanical stirrer. We recommend to make use of the pumps gauge and stay above 5.8 kPa or 1.7 inches of mercury to avoid boiling off the alcohol! :)

Vacuum-forming
https://www.youtube.com/watch?v=YRYygUcGqiI

Forming of plastic parts using negative shapes, described in just 5 minutes along with the piping and setup. For this technique facilitating a vacuum buffer (a surge tank) is often useful and avoids to have to buy monster pumps at the same time.

Degassing silicone
https://www.youtube.com/watch?v=bbSvzD8g_S0

Silicon is used to prepare casting molds, but needs to be free of bubbles to allow the cast to cleanly divide from the mold as well as for perfect surfaces. The video demonstrates the proper degassing procedure facilitating a vacuum tank with an translucent acrylic lid.

Stabilize driftwood
https://www.youtube.com/watch?v=5CLdQTtQYwE

Working with wood that is partially deteriorated is often giving nice results due to the unique texturing caused by fungus or sea water. To make that wood last, proper preservation is necessary. In this video is shown one way to do it.

Common problems and Solutions

7.1 Is it necessary to refill oil?

Answer: Yes. Rotary vane pumps are quite sturdy devices when well designed. The most important point is to keep the oil filling on the required level. The moving parts in the pump needs constant lubrication to seal of the vacuum properly and to avoid overheating. With not enough oil in the tank the pump overheats and starts boiling the oil. This is a frequent source of excessive oil mist and noises.

7.2 Do we have to use professional vacuum oil? Can you replace it with other oil?

Answer: Vacuum oil is a specialized oil with a very high vapor pressure that prevents the oil from steaming of under vacuum. If the wrong type of oil is used or the correct oil is contaminated by water or solvents that came with the evacuated gas, then the oil will appear cloudy or seem to boil when under vacuum. The evaporating water or solvents will carry oil droplets along and potentially overload the oil mist separator, so that it can not hold back the oil properly.

Use only the proper oil. Car oil and similar products are not useable. Use a cold trap if you have to evacuate excessive amounts of gases containing water or solvents to separate them from the gas stream before they reach the pump. Exchange vacuum oil that is cloudy or discolored or smells like solvents.

7.3 My vacuum pump is very hot. After continuous use for an hour, it suddenly stopped working, what should I do?

Answer: If the pump runs for a while without creating vacuum, the motor may overheat and stop. Both continuous working time and container size should been taken into consideration. The following situation often cause overheating：

A. Long continuous operation
B. The volume of the container is too big and does not match the vacuum pump
C. Vacuum oil is improper or not been replaced in time

The BACOENG pumps come with a thermal protection for the motor that turns off the motor before irreversible damage is happening. Wait until the motor has cooled down sufficiently and then start again. Do not let the pump run for long times without vacuum building up. Under vacuum the pumps has to carry much less load because it only moves the little bit of air leaking into the system.

7.4 Does the liquid and leak weaken the vacuum?

Answer: Yes. Leaks or liquids in the vacuum system are disturbing sources of gas for long times or forever. Very deep vacuums below the vapor pressure of intruded liquids can not be achieved, as long as there is still liquid. When reaching deep vacuum the liquid starts boiling and creates large amounts of vapor that keep the vacuum weak.

Solution: If you let water into vacuum pump inadvertently, vacuum pump oil will be soon emulsified which will overload the motor, cause strange noise, overheat, lack of vacuum and even damage the internal parts. You‘d better replace vacuum oil and dry the vacuum oil tank.
If a few liquids are in the system, dry out the vessel and pipes manually or try to evaporate all the liquid by applying vacuum for a long enough time.
Search leaks by slightly pressurizing the system and apply soap water on the potential weak points. Look out for bubbles forming and redo the connectors or fix the leak.

7.5 I've been using the pump for three months, and there's a lot of oil mist coming out of the oil cap lately, is that normal?

Answer: Vacuum oil provides lubrication for the rotation of the vacuum pump motor. In this process, it will produce oil mist which cannot be avoided no matter what brand it is. If the vacuum pump is not working properly, overheating, or making loud, grinding noises, this will also cause oil mist.

Solution:

1. Oil mist is always caused by improper handling, so please make sure using vacuum pump correctly.

a. Don't run overload.

b. Don't pump atmosphere.

c. Use proper vacuum oil. No.100 recommended.

d. Add oil to middle of tank scale.

e. Exchange oil that is cloudy or discolored or smells like solvents. Recommand once a month.

2. Install oil mist separator. There are 2 types separators: fundamental and industrial. BACOENG pumps can be equipped with a fundamental separator which can filter most oil mist. The industrial filtering effect is better which can filter 90% oil mist, but costs dozens of dollars . If you need it, you could purchase on www.bacoeng.com.

3. While using vacuum pump, pay attention to the sound pump makes. If the noise is too loud, inspect the pump.

* How to identify if oil mist is normal?

In determining the correct operation method and reasonable pump noise, the oil mist is regarded as normal.

7.6 Were you able to pull a full 30" of vacuum? I could only get 27" which is 10% too low for proper AC evacuation.

Answer: Normal vacuum pressure gauges show relative pressure. Therefore any measurements are dependent on the atmospheric pressure, which is dependent on height above sea level and air conditions. Let’s say we have a certain vacuum at sea level and the gauge shows -0.095 MPa (-28 inHg). At 900 m or 2950 ft height above sea level the same vacuum gives -0.085 MPa (-25 inHg) on the gauge, although the vacuum quality in the two situations is exactly the same.

Generally, this model of vacuum pump is supposed to be able to achieve 30" of vacuum, more specifically it should reach 29.9", or 99% of vacuum, which is good enough for AC evacuation. However, what you reached in only 27", which is 90% of vacuum, or around 70,000 microns, it is far above ultimate this vacuum pump can reach. Please check if there is anymore leaking, or stop valve and turn off the vacuum pump for a few minutes to see if there is anything leaking. If you are sure this is due to the vacuum pump malfunction, please return to Amazon to get a full refund. If you have any further question, please contact us to get support.

7.7 I have installed and used this vacuum chamber in accordance with the instructions, but it is still not sealed.

Here attached correct steps for you:

1.Open the top cover of the gauge(on the chamber)

2.Tighten the joint and keep seal

3.keep the chamber cover clean,and press the cover tightly to let it suck the chamber

Now, we will analyze several possible scenarios are analyzed that lead to non sealing:

1.There is something leak, according to the instructions to determine the leak point (pump, pipe joints, barrels), if it is barrel leak, and then check which specific parts of the leak (table, valve, silicone ring), we will send you the relevant accessories.

2. Silicone rings may be dusty and please clean or wipe it with water.

3. When you vacuum, please press the silicone ring

4. Uneven edge of vacuum chamber will lead to leakage (the possibility is relatively small because of full inspection), if it is, we will resend a new barrel to you.

7.8 Vacuum pump pulls vacuum very well however it leaks oil back into the tube and chamber, contaminating the experiment being performed. Is there anything wrong?

Answer: It could be that some seal in the pump is not in place. Oil are sucked out of the pump due to pressure differential. Please operate it as below:

1. When you want to stop working, closing the exhaust valve on the vacuum chamber first and then turn off the pump.
2. When you want to start working, turning the pump first, then the exhaust valve.

What should I do while failure occurs?

We suggest you reading our CUSTOMER FEEDBACK SURVERY first. Pls see below.

Generally, 95% product problems can be solved after your self-checking. If you still cannot solve your problem, please fill it out, then send back to us so we can figure out exactly how to assist you.

BACOENG Official Email Address:

sales@bacoengineering.com support@bacoengineering.com

BACOENG After-Sale Service Hotline: + 1 (855) 969 - 4361

Parts and Fittings for Vacuum Series

Please visit our website to purchase.
https://bacoeng.com/collections/vacuum-pump-chamber-parts-fittings

If you have any problems about vacuum pump, pls feel free to leave messages below. We will answer you ASAP.

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