Achieving High Vacuum Levels With a Micro Air Compressor
In this article we’ll look at a couple of methods you can use to boost the vacuum levels you get from a micro air compressor. Specifically, we’ll take a look at Turbomolecular pumps and liquid ring pumps. We’ll also discuss ways to avoid liquid slugs in your vacuum pump.
Liquid-ring vs. ejector pumps
When choosing a pump to handle a vacuum application, it is important to know whether liquid ring or ejector pumps are appropriate. These types of pumps differ in design, construction, and function. Although they can both create a high vacuum, they also have their own advantages and disadvantages. For example, if a system requires the creation of a vacuum in a high pressure region, it is likely that a liquid ring pump is more suitable. On the other hand, if the process requires a lower vacuum, then a ejector is the ideal solution.
A liquid ring pump is similar to a rotary vane pump. The difference lies in the fact that the ring of liquid moves against the axial wall of the pump housing. This provides a seal between the impeller vanes. This is done to prevent leakage of gas from the pump.
Another feature of a liquid ring vacuum pump is that it can evacuate gases that contain steam. They are generally capable of producing an intermediate vacuum of 50 to 100 mbar. Liquid-ring pumps are most commonly used in the process industry, but can be useful in other situations. Typically, they are powered by an induction motor. Other common motive fluids include air, nitrogen, and steam. Whether they are used in vacuum degassing or other processes, they are ideal for handling explosive gases.
Unlike liquid ring pumps, ejectors can be made of a wide variety of materials. Some are metal, while others are made of plastic or fiber reinforced. Ejectors are very simple to operate and require minimal maintenance. Additionally, they offer the lowest cost of capital. Moreover, they have the highest throughput capacity.
Both liquid ring and ejector pumps can be operated in series or in parallel. If the pumping speed curve is variable, then it is possible to use a kinetic transfer pump in place of one or both of these systems. Kinetic transfer pumps are designed to provide superior performance in a wide range of applications. Generally, the throughput and compression ratio of the pump are optimized through a variable pitch model. However, these models are often less efficient than liquid ring models. In addition, kinetic transfer pumps may not have sealed volumes.
A liquid ring vacuum pump has a low power consumption. Because of this, they are ideal for applications where a long operating life is required. They are also capable of handling fire, dust, and ice water. Their efficiency is not impacted by metal-to-metal contact, which is advantageous for these types of applications.
As compared to ejectors, liquid ring pumps have a low operating cost. They can work at a higher vacuum than ejectors. Depending on the design and the process, the amount of energy consumed can be quite low. They are especially effective when handling sensitive process fluids.
Avoiding liquid slugs in vacuum pumps
The best way to avoid liquid slugs in a vacuum pump is to use a micro air compressor. This patented device combines a centrifugal force with a high-pressure once-through oil to draw process gas and lubricate moving parts. Designed to operate in ambient conditions, it can be a cost effective solution to the problem. It is also a great way to avoid liquid migration back into the system on the off-cycle. However, there is a downside. One common problem with such pumps is that they can become overwhelmed with a large amount of process gas, and a high flow rate can lead to clogged rotors and valves. For these reasons, designers should be savvy about the tradeoffs involved when selecting an onsite source for vacuum pump supplies. Similarly, a proper sizing and configuration of the micro-compressor can be the difference between a satisfactory pumping performance and a slug fest. To achieve optimum results, it is important to determine the optimum balance between high pressure and low flow rate. A suitable combination was determined using a series of tests under a wide range of atmospheric conditions.
The trick is to select an opportunistic combination that offers the best value for money without sacrificing performance or reliability. This is an ongoing challenge in the vacuum industry, and one that can be solved by careful design and implementation. Ideally, a micro air compressor should be used as a last resort, preferably in conjunction with a larger, more powerful unit. There are a few things that engineers must consider before installing such a unit, such as the number of vacuum ports required, the type of fluid to be drawn from the apparatus, and the maximum ambient temperature at which the machine operates. Once these factors have been taken into account, the project can be set up and commissioned for testing.
To test this hypothesis, a small scale capillary microreactor was fabricated using a polyether ether ketone. In fact, the micro-channel used for the experiment was not much bigger than a tenth of a centimeter in diameter. Although the system had been rated as one of the lowest cost, it still had to be carefully controlled. It was also necessary to use a syringe pump to deliver the nanofluid, which was dispensed in micron-sized beads to prevent bubble formation. During the experiment, the most important parameters were recorded, including the slug length, flow rate, and the liquid’s density. By using the aforementioned data, it was possible to determine the optimal flow rate and slug length for a variety of nanofluid concentrations. Moreover, by employing a Y-junction mixer to provide a uniform flow of nanofluid, it was possible to determine the magnitude of the nanofluid’s signature properties and to determine how it interacts with the surrounding environment.
Turbomolecular pumps
Turbomolecular pumps are a type of vacuum pump that has been used for a wide range of applications. They can produce vacuums up to 10-11 mbar, and are ideal for ultra-high vacuum applications. However, the performance of turbomolecular pumps can vary considerably depending on the types of gas they are working with. Therefore, it is important to choose a turbomolecular pump that is appropriate for your application.
In general, a turbomolecular pump works on the principle of collision. The rotating blades of the rotor hit the molecules in the chamber. These are then released into the simulation domain. This results in an optimally compressed volume of gas. It is important to note that the compression ratio of a pump varies exponentially with the molecular weight of the gas being pumped.
A typical turbomolecular pump stage might contain eight or twenty rings of blades. This stage should be made up of a combination of rotating and stationary blades. Ideally, the blades should rotate at a speed equivalent to the mean thermal velocity of the gas being pumped. Generally, light gases have higher thermal velocities than heavy gases.
As the speed of the rotating blades increases, the mechanical energy of the blades is transferred to the gas molecules. Each molecule is subsequently reflected in random directions. Thus, this process is often referred to as a “drift velocity.”
The number of rings of blades is not necessarily an indication of the degree of pumping efficiency. The number of rings can be very large, but should not exceed a minimum of one meter. Similarly, the speed of the rotors is not necessarily a good indicator of the rate at which the molecules are pumped. Instead, the speed of the rotors may be an indicator of the optimum flow conditions at the inlet of the pump.
To achieve a high vacuum, the turbomolecular pump needs to operate at a high rate. This is achieved by employing a fast-spinning fan rotor. In most cases, the rotation rate is between 20,000 and 90,000 rpm. If the pressure is extremely low, the rotor can be rotated at a rate of tens of thousands of revolutions per minute.
However, the real power of a turbomolecular pump comes from its ability to reduce the pressure in the chamber to ultra-high vacuum levels. Specifically, these pumps are able to attain total pressures lower than 1×10-10 mbar, which is a significant advantage.
Despite the high speed and low pressures involved, turbomolecular pumps are relatively durable. They can be expected to last for more than two hundred thousand hours of operation. Additionally, the technology is oil-free. This makes them a suitable choice for a wide variety of clean and harsh applications.
Although turbomolecular pumps are capable of achieving ultra-high vacuum conditions, they cannot work at atmospheric pressure. Therefore, they need to be connected to a vacuum chamber in a sealed environment. There are a few ways to do this. First, you can use a rotary vane or piston pump. Alternatively, you can connect the pump directly to a chamber with cooled baffles.
