Before getting straight to the point, we must understand how internal combustion engines work.
You might think the engine in your car runs on gasoline, and that’s it. Most of us are like that, but not like that. It runs on air, especially expanding air.
That’s what pushes the piston and turns the crank.
The electric spark ignites the compressed air-gasoline mixture, causing combustion that blows the piston down the cylinder.
The piston is connected to the crankshaft, which converts the up and down motion of the piston into rotational motion and the crankshaft then drives the rear wheels.
So, the point is – the more air an internal combustion engine can hold, the more power it produces.
A supercharger increases the pressure or density of air entering an engine to increase its efficiency and power.
So, what’s the difference between a supercharger and a blower? Let’s take a look.
What Is A Supercharger?
A supercharger is more than an air compressor that injects more oxygen into the engine, producing more power.
It is like an air pump bolted to the engine to increase the pressure or density of the air feeding the engine.
It pumps extra air into the engine to increase its intake manifold pressure and is mechanically driven by a belt, chain, or gear on the crankshaft or an electric motor.
The air is accelerated to a high speed and then decelerated to increase the pressure.
Air enters the impeller, where centrifugal force throws it out of the compressor housing, where speed is compressed at high pressure, which significantly increases power without lag.
So, in a nutshell, what a supercharger does is increase the power the engine produces by pumping an air-fuel mixture (or air) into the engine at a rate that exceeds atmospheric pressure.
Superchargers are used as exotic modified street machines or race cars.
What Is A Blower?
Every blower is a supercharger, but not every supercharger can be a blower.
A blower is just another name for a supercharger, especially the Roots-style supercharger, probably one of the oldest superchargers.
At the heart of the root, the supercharger is two counter-rotating meshing lobed rotors.
The two rotating rotors trap air in the gaps between the cams as they spin, allowing air to move from the intake port at the top of the supercharger to the bottom outside the rotors.
Technically, root-type superchargers don’t compress air inside the supercharger; instead, they push air into the intake manifold and the engine.
This type of supercharger is sometimes called a “blower” rather than a compressor.
These car superchargers usually have rotors with twisted lobes to ensure low vibration and quiet operation.
Now that we have understood each of them, let us go into the nitty gritty of their core differences.
1. A supercharger is more than an air compressor device designed to increase the pressure that pushes air into the engine to increase its density so that the engine has a more oxygen intake cycle.
Superchargers are used as exotic modified street machines or race cars.
A blower is just another name for a supercharger, especially the Roots-style supercharger, probably one of the oldest superchargers.
2. A supercharger and a blower serve essentially the same purpose – to pump air into the engine at a rate above atmospheric pressure –
The supercharger is mechanically driven by a belt, chain, gear, or electric motor on the crankshaft, while the blower uses centrifugal force to push the air forward.
Roots blowers don’t compress the air inside the supercharger; instead, they push air into the intake manifold and the engine.
3. The supercharger is designed to increase the engine’s volumetric efficiency by creating positive boost pressure in the engine manifold at some point within its operating range.
Roots blowers rely on two counter-rotating meshing lobed rotors to create a positive displacement pump.
The rotors are precisely synchronized with each other, maintaining a narrow gap between the rotors at all times.
Air is trapped in the gap between the cams as they spin, passing under it and forcing it into the engine.
In summary, both the blower and the supercharger are designed to increase the engine’s efficiency and power by pumping additional air into the engine to increase the engine’s intake manifold pressure, thereby increasing the engine’s volumetric efficiency.
Well, all blowers are superchargers, but not all superchargers are blowers.
The blower is another name for a supercharger, especially a Roots-type supercharger, which was the first to appear, and probably the first to think about talking about superchargers in general.
How Does a Blower on a Car Work
A ‘Blower’ is another name for a compressor, specifically ‘Roots’ type compressors which use long figure-8 shaped blades to force or ‘blow’ air into the motor.
In terms of performance, the only “disadvantage” of using a blower is that it is belt driven by the crank in cars.
It uses some power from the crank to spin the blower, which is the power that could otherwise drive the wheels. It is offset by the fact that the blower allows the engine to make a lot more power.
While a turbo uses the exhaust gases pumped out of a car to spin an impeller that rotates the turbo propeller, this creates pressure simply due to the displaced air volume rather than to prevent the air from escaping.
Turbo recycles waste to increase the power of the engine through the use of exhaust gases.
WHAT IS A BLOWER AND ITS TYPES
In the previous article, I explained what a blower is. So let me tell you the types of blowers available. They are listed below:
- Positive Displacement Blowers
- rotary Lobe Blowers
- helical Screw Blowers
- Centrifugal Blowers
- Multistage Centrifugal Blowers
- High-Speed Blowers
- Regenerative Blowers
What is a Positive Displacement Blower?
A positive displacement blower conveys gas or air from the upper inlet port into the stage using two parallel rotary pistons.
These are mounted within a housing, also called a conveying chamber.
The pistons rotate opposite directions and facilitate gas or air conveyance from top to bottom.
Positive displacement blowers are also known as PD blowers or rotary air blowers.
How does Positive Displacement Blowers work?
There are two types of positive displacement blowers;
1. Lobe
2. Screw.
Lobe positive displacement blower conveys a relatively constant volume of gas from the inlet to the discharge point. It follows the isochoric compression principle, also known as external compression.
In this principle, the medium (gas or air) is forced from an atmospheric condition into a system with a given resistance (back pressure) to achieve the relevant pressure increase.
For this reason, positive displacement lobe blowers are not considered compressors.
The amount of gas the machine handles is fixed by the configuration of its casing and its rotating parts.
In the screw positive displacement blower, the rotors turn in opposite directions and maintain precise alignment using timing. When the rotors mesh, they form a series of working chambers between the rotors and the casing wall.
The gas is sucked from the intake side (suction) and trapped between the rotors and the casing (radially) and the cover (axially).
It is then transported to the compression side (discharge), where the working chamber shrinks, and the air or gas is compressed.
The internal compression leads to a supply of steady, non-pulsating air flow.
It minimizes vibration and maintenance to maximize the lifespan of the blower.
ROTARY LOBE BLOWERS
The rotary lobe blower accommodates the renowned RBS air end. This rotary lobe blower provides an excellent solution for the oil-free conveyance of air and neutral gases. It is equipped with a low-pulse system that reduces the residual pressure pulsation of the conveyed gas below 2% of the operating pressure.
Centrifugal blower
The centrifugal blower uses the centrifugal force generated by the rotating rotor with many blades to squeeze the air to achieve a certain air volume and pressure.
This type of compressor is called a centrifugal compressor because it continuously sucks in the refrigerant vapour and is continuously thrown out in the radial direction when it is working.
The number of working wheels installed in the compressor is divided into single-stage and multi-stage types.
If there is only one working wheel, it is called a single-stage centrifugal compressor, and if it is composed of several working wheels in a series, it is called a multi-stage centrifugal compressor.
In air conditioners, single-stage is generally used due to less pressure increase, while centrifugal refrigeration compressors used in other aspects are mostly multi-stage.
The structure of the single-stage centrifugal refrigeration compressor is mainly composed of a working wheel, a diffuser, and a volute.
When the compressor is working, the refrigerant vapour enters the suction chamber axially from the suction port. The diversion effect of the suction chamber guides the refrigerant vapour from the evaporator (or intercooler) evenly into the high-speed rotating working wheel.
(The working wheel is also called the impeller, an important part of the centrifugal refrigeration compressor, because only through the working wheel can the energy be transferred to the gas).
Under the action of the vane, the steam rotates at high speed with the working wheel, and at the same time, under the action of centrifugal force, it diffuses and flows in the vane channel so that the pressure and speed of the steam are improved.
The gas from the working wheel then enters the diffuser, whose cross-sectional area gradually expands (because the gas has a high flow rate when it flows out of the working wheel.
The diffuser partially converts the kinetic energy into pressure energy, thereby improving the gas flow rate Pressure).
As the gas flows through the diffuser, the velocity decreases, and the pressure increases further.
After the diffuser, the gas is collected into the volute and then led to the intercooler or condenser through the exhaust port.
What Is A Regeneration Blower?
Regenerative blowers are machines used to move the air by non-positive displacement methods.
A positive displacement device captures a certain amount of air and forces it to move a given distance in a given direction.
However, how the regenerative blower moves the air allows some of the air passing through the impeller blades to slip past it.
The air moves forward through the other blade.
The structure of the regeneration blower is relatively simple. It consists of impellers that emanate from the blades.
The impeller is enclosed in a casing, and there is no gap between the tips of the blades and the casing, so they do not touch.
Air flows into the blower from the intake port and exits from the exhaust port.
Regenerative blowers are used in many applications, from heavy industry to chemical and environmental processes.
They are used in operations such as packing, lifting, and transporting products in factories, dust removal, fume removal, sewage aeration, and soil vapour extraction.
Generally, regenerative blowers are best suited for applications that require high air volumes at low pressure or where a vacuum is required
An electric motor or engine drives the impeller to rotate the blades within the housing to operate the blower.
The blower draws in air through the air inlet, which, as it enters, comes into contact with the blades on the impeller.
Contact with the moving blade accelerates the air, which moves it outward toward the housing.
Compressed air is expelled from the blower through the exhaust port, but not all air touched by a given blade is expelled immediately.
The annular space between the impeller blades and the housing allows some air to slide over the first blade in contact with it.
For this reason, regenerative blowers are sometimes called ring compressors or ring blowers. This air falls to the bottom of subsequent blades.
This air is then re-accelerated in the same way as the first blade by contact with the second blade.
Regenerative blowers operate efficiently and are generally relatively compact due to the large volumes of air they move.
They produce less noise than many other blowers and generate virtually no vibration when operating under a dynamically balanced impeller.
The impeller is the only moving part in each unit, and the regenerative blower is reliable with little to no wear.
Therefore, they require little maintenance or downtime.
Minimum clearance between the impeller and housing is required to keep debris out of the blower to ensure trouble-free operation.
Filtering the air before it enters the blower is a great way to keep the equipment clean and the impeller moving freely.
The equipment may be damaged if the impeller and housing lock are damaged.
Some regeneration blowers rely on the airflow through them for cooling. Over-pressurizing the unit can cause airflow to slow or stop, preventing necessary cooling.
If the blower impeller heats at a different rate than the casing, it may be sized faster than the casing.
This mismatch can cause impeller movement to be impeded by contact with the casing. It can also lead to catastrophic failure.
It is one of the most comprehensive articles on blowers you could ever come across. I hope you enjoy reading it.