Vacuum Pumps - Rotary Vane Pumps - Self Priming Pumps

Today, there is a bewildering range of centrifugal pumps available commercially. For pumping of great volume of fluids, slurries and liquified gases, centrifugal pumps make up the vast majority.

Due to its varied applications, a galore of centrifugal pumps are available in the market with diverse specifications in types, shapes and sizes. One can find these pumps in multifarious forms, whether the requirement is for high pressure, low pressure or handling liquids or gases.

Despite of the broad usage and availability of centrifugal pumps, nowadays industries opt self priming centrifugal pumps because of two major reasons: its ability to handle solid-laden liquids and slurries without any trouble and its cost effectiveness. Self priming pumps are primarily known for its quality to automatically reprime itself without the need of suction or discharge check valves. This is possible as it creates and maintains its own sufficient vacuum.

However, frequent troubles in mechanical seal have given rise to sealless variety of pumps. Magnetic drive pumps fall under this category. To create a static shaft seal, a magnetic drive pump uses a magnetic coupling which leads to generation of magnetic force. This force aligns outer and inner magnet via a stationary containment shell. Thus, the need of seal and risk of leakage is completely eliminated. This characteristic makes a mag drive pump a preferred choice to handle corrosive, combustible and highly viscous liquids.

Irrespective of the industrial sector, if one is looking for robust pumps mentioned above then Premier Fluid Systems Inc. is one of the most reputed and trusted firms. It is the unrivaled marketing leader not only for pumps but a wide portfolio of vacuum systems and liquid ring compressors.

Today, there is a wide array of vacuum pumps available in the market. Liquid ring vacuum pumps are one of core type of vacuum pumps and a preferred choice for diverse applications like power generation equipment, petrochemical, seawater de-aeration, pharmaceutical, ground water vapor extraction and food production amongst others.

A liquid ring vacuum pump gives definitive advantage over other vacuum pumps as there is only a single rotating part, a multi-bladed rotating impeller to produce an enormously high pressure. This impeller keyed to the pump shaft, is mounted eccentrically in a round pump casing. When the shaft spins the impeller, centrifugal force drives the liquid to the outer edges of the chamber and draws the gas molecules inside through a valve. These molecules of gas are ultimately compressed and pushed out through the exhaust valve. A sealant fluid used in the liquid ring pump forms a ring around the inside of the casing. This ring of liquid acts as a seal. Popular liquid that can act as sealant includes water, ethylene glycol, mineral oil and organic solvents.

Liquid ring pump is known for its longer life and low-cost of maintenance as it does not require many vanes or valves. Besides, because the operation of this pumps hardly causes any noise and vibration, it can be easily installed in most locations.

Other advantages of liquid ring pumps are:

• Uncomplicated design compared to other vacuum pumps


• Can be constructed from any castable metal


• The temperature of the discharged gas shows very little rise


• Easy maintenance

With all these advantages and its versatility, the balance definitely tilts towards the liquid ring pumps and opting for it would be a wise choice.

A vacuum pump works on the principle of suction mechanism. It operates by moving air into or out of an object. This pump is extensive used across diverse industries such as paper, sugar, coal, mines, chemicals, pharmaceuticals, fertilizer, oil refineries, railways, textile, food processing, dairy, paper, petrochemical, process, distilleries, plastic, breweries, cement, water & effluent treatment plants etc.

Vacuum pumps can be broadly classified into 3 categories:

• Positive Displacement Pump – best effective for low vacuum applications


• Momentum Transfer Pump – also known as Molecular Pump. Often employed in conjunction with displacement pump


• Entrapment Pump – used for ultra high vacuum needs over a short period of time

Liquid ring vacuum pumps are most commonly used vacuum pumps. Liquid ring pumps are type of positive displacement pump which are also utilized as gas compressors.

With the advancement in technology, increased number of vacuum pumps are available in the market which are highly useful for a host of applications for both, home as well as industrial purposes. Some of these applications include, vacuum filtration, moisture extraction, evaporation, vacuum distillation, vacuum condensation, solvent extraction, separating water from paper pulp to name a few.

If you are looking for a robust vacuum pump then there are several options available to choose from. One of the most reputed and trusted firm is Premier Fluid Systems Inc. It is the leader in marketing and servicing pumps and systems of Travaini, PVR-Rotant and other quality brand names. Along with the extensive product line of different vacuum pumps, the Company’s product portfolio also includes highly efficient magnetic drive pumps, centrifugal pumps, self priming pumps and mini pumps.

Essentially, centrifugal pumps are used in industries that need to transport liquids from one point to the other. To increase the fluid pressure and move the pressure through a central piping system, centrifugal pumps use centrifugal force and rotating impellers. These pumps are accompanied by an in-built robust mechanical seal that protects the inner shaft of the pump.

Depending on the usage, centrifugal pumps are available in different types. The most common type being single-stage centrifugal pumps. However, for higher pressure and enhanced quantity of liquid, industries prefer to use multi stage centrifugal pumps. They encompass more than single impeller mounted on common or separate shafts.

Another category of centrifugal pump includes magnetic drive pumps. This class of pumps are the most advanced, sophisticated and expensive type. Magnetic drive pumps use magnetic field to link a motor and an impeller with pump fluids and this facilitates to increase its pressure. Because of the presence of magnetic field, it does not require shaft or seal between the motor and impeller unlike single-stage pump. This feature renders magnetic drive pumps the edge over the other pumps and significantly reduces the internal corrosion, contamination and friction loss.

Adding to the list of different categories of centrifugal pump is self priming centrifugal pumps. A self priming centrifugal pump is designed for economical and trouble-free pumping of water, slurry, dyes, oil etc. It is fabricated to include a large volute that allows it to re-prime itself when under lift conditions. It eliminates the need for suction as well as discharge check valves thus providing prolonged operation without the problems of clogging.

There are different types of vacuum pump available in the market. Each one has its own unique features that makes them different from others. This is where liquid ring vacuum pump is most preferred by the different industries for different applications.

Liquid ring vacuum pump is a member of the rotating displacement pump family which is known for its low price and wide range of applications. Also these type of pumps are well known for low maintenance and its long lasting nature, which makes it popular among the industries. The only drawback of this type of pump is that it cannot be used for large industrial applications. These pumps compress the gases by using the rotator vanes located within the cylinder shaped casing. Then water or any other liquid is forced into the pump and the centrifugal force inside the pump causes a ring to form around the inner lining of the casing. A series of seals are used to create separate compression chambers. Gases becomes trapped in these chambers and become compressed.

The next question that arises is where to find liquid ring vacuum pumps. These pumps can be found offline as well as online. But most of the clients would think of directly ordering them online. It is better to purchase the product directly from the manufacturers. But for this the exact name of product is necessary. Also it is necessary to know whether purchase can be made directly from the manufacturer's website. For example, if the product's name is Siemens model 2B, it is better to make the purchase from the official Siemens website.

It is also important while purchasing that you know everything about the different makes and models of liquid ring vacuum pumps that are available in the market and for what applications they are used as every model of the pump cannot perform every function. Even ignoring a single thing about the pump could lead to a wrong investment by the purchaser.

There are few other questions to ask before making a purchase such as following:

• Operating range and cut in point for the machine.


• Highest level of pressure at which it can operate constantly


• Highest temperature at which it can operate.


• Temperature at which the system will automatically shut down.

To ensure consistency and quality throughout the entire assembly process, every manufacturing unit is equipped with machines that operate on vacuum systems. A vacuum system necessarily comprises of vacuum pumps. Vacuum pumps are devices that work on the principle of removal of gaseous molecules from a fixed volume and thus creating a vacuum. Vacuum pumps come in several diverse types of models and varieties with different mechanisms and applications but their fundamental principle remains constant.

The segment of rotary vane pumps are included in these vacuum pumps. A rotary vane pump is a positive-displacement pump consisting of vanes attached to a rotor that rotates inside the cavity. This causes a vacuum in the center of the pump creating a suction and a void. To fill this void water or other fluid enters into the pump via an inlet valve. Once the fluid is inside the pump, the intake valve shuts and subsequently the outlet valve opens up. These series of events allow the fluid to flow back outside through another path.

Rotary vane vacuum pumps are of two different types. The non-lubricated pump, also referred to as an "oil-free" pump while other type is lubricated pump. Both the types of rotary vane vacuum pumps operate on the same theory but used for different applications.

Rotary vane pumps are one of the most widely used vacuum pumps in manufacturing industry. Their most common use in daily life is removal of water from the basement of buildings. The rationale for using a vacuum pump is, water needs to be moved upwards and this is possible only by creating enough vacuum that will eventually draw the water inside the pump and then push it uphill into the outer area.

Since countless years now, these pumps have been providing revolutionary changes across industries and enriching millions of lives.

For low-pressure solutions, a large number of applications utilize vacuum systems. Essentially, a vacuum system ensures the equipments and products work smoothly. This is because under low pressure conditions, there are less air particles which can cause damage. However, a vacuum system needs an efficient vacuum pump. A vacuum pump is required to remove air, gas or liquid from an enclosed container. This results in formation of low pressure (or vacuum). Factors that influence the selection of an appropriate vacuum pump includes the amount of vacuum produced, the power that is needed to produce it and the flow of air removal amongst others.

The three major categories of vacuum pumping technology employed in vacuum pumps are:  

1. Positive Displacement Pumps


2. Momentum Transfer Pumps


3. Entrapment Pumps

Some of the key applications of vacuum pumps from the extensive list are in: flight instruments, hydraulic brakes, cruise control systems, manufacturing processes like vacuum tubes and electric lamps, various medical procedures and vacuum coating amongst others.

One of the type of positive displacement pumps is a liquid ring pump. Along with its application as a vacuum pump, liquid ring pump is also used as a gas compressor. It compresses the gas by rotating a vaned impeller. As the name suggests, liquid is flowed into liquid ring compressors and by centrifugal force, it forms a moving cylindrical ring to form the compression chamber seal. Liquid used in liquid ring compressors should have appropriate vapour pressure. In most cases, water is used as the sealant liquid.

Another variant of pump is sealless ones and magnetic drive pumps are the flagship pumps under this category. The application scope of these plastic lined magnetic drive pumps is witnessing a striking growth especially in chemical and pharmaceutical industries.
Magnetic drive pumps use a standard electric motor to operate a set of permanent magnetic coupling which in turn are used to transmit torque to the impeller without the need of a seal.  These pumps are very important for pumping of highly toxic and corrosive liquids like acids, adhesives, chemicals, lubricants, coolants etc.

There are several type of vacuum systems available in the market to meet the different needs of different industries. But sometimes it is possible that one cannot find the vacuum pump of his needs and so it needs to be custom built. And this is the most exciting and unique feature of vacuum pumps. Because of number of options in vacuum pumps it is good to gather information about the different options and about your need and then make your decision.

One type of vacuum pump is the rotary vane pump. They are a part of positive displacement pump category. They move the fluid through the pump using the rotating assembly in the pumping chamber. It usually takes one or two rotating vanes to move the gas or the fluid from the inlet to the outlet. As the bulk of the fluid is transferred by the rotary vane pumps the end of the vane barely brushes the housing part and thus creates the seal from the inlet to the outlet.

The movement of the pump can be broken down into three different phases in the rotary vane pumps:

1. Gas or the fluids move through the inlet.


2. The vanes rotate either clockwise or anticlockwise to seal the media between the vanes and the housing wall. Due to the fluids, this volume should remain constant throughout the entire cycling process.


3. Then the gas or fluid is moved through the outlet. The rotor blades are positioned in such a way that it contains a specific volume of the fluid. Due to the cyclic movement of the vanes it creates a smooth flow as the gas or fluid is transferred through the pumping chamber.

Following characteristics of vanes make the rotary vane pumps being used widely by different industries for different applications:

• Can be made from several materials.


• Have the flexibility of being able to choose the inert gases and many different type of gases.


• Can either be internal or external.


• Can also be rigid or flexible.

One will wonder whether these options will be available when he purchases the rotary vane vacuum pumps already assembled. But one can tell his needs in the pump and it can be customized. There are other things that need to be considered while rotary vane pumps is being built. The surface dimensions of the housing and the rotary assembly might be considered while calculating the flow rate. The other requirements that might be included is the vacuum service or air compression.

There are various other options, but this can give the idea of what a rotary vane pump can do.

The self priming pumps are a special form of centrifugal pump that eliminates the necessity for external priming devices. If a centrifugal pump is found on top of the suction vessel or sump , it should be primed before it is started, to get rid of air from the suction line and casing, and to fill the suction line and casing with liquid. This should be done before starting the pump, otherwise the pump won't pump, and the air can harm the pump bearings. The priming operation on a regular centrifugal pump that's operating with a suction lift is done by pulling a vacuum at the top of the pump casing, using a vacuum pump or the plant vacuum systems. A self priming pump eliminates the requirement for this external priming mechanism.

The operating self priming centrifugal pumps work like any other pump that's operating with a suction lift and that has been properly primed. When the pump shut down or stops working, the liquid drains out of the suction line and back to the sump. However, as a result of the special design of the over-sized self priming pump casing, a amount of liquid remains within the bottom of the casing. When the pump is started again, the pump goes through a priming cycle, which generally takes several minutes. Throughout the priming cycle, the liquid that had remained in the pump casing is pushed by the impeller out the discharge, along side some of the air that is in the casing. This creates a vacuum at the impeller inlet, which draws liquid up the suction line. The priming cycle continues till all of the air is pushed out of the discharge and the water has worked its way up the suction line to the impeller. Then, the pump is totally primed and begins pumping like every primed centrifugal pump.

Self priming pumps can be used anywhere where a pump is running with a suction lift. The pump is also costlier than a regular centrifugal pump, however it eliminates the external priming mechanisms, and eliminates any bearings or motors in the sump that other pump types would possibly need. Normally, suction lifts are restricted to approx. twenty feet with self priming pumps.