What is the Difference Between Blower and Compressor?

Blower and compressor are both machines that convey air power, and both are widely used in industrial fields.

Despite this, they still have some differences in terms of type, working principle, work pressure, application industry, etc.

Let’s have a check.

What is the Blower?

Blowers are mechanical or electro-mechanical devices used to induce gas flow through ducting, electronics, process stacks, among other things. They are most commonly used to carry out gas circulation, such as in heating, ventilation, and air-conditioning (HVAC) applications.

In simple words, a blower intakes gas (mostly air) and propels it at high-speed outwards. These devices are primarily centrifugal, meaning they ramp up the speed of air inflow using a rotating impeller (a specialized fan) and convert it into pressure as it heads to the outlet on the circumferential periphery.

Types of Blower

Blowers are categorized into several types, depending on their application, design, and operational mechanism. Here are some commonly used types of blowers:

Centrifugal Blowers

These blowers use a rotating impeller to increase the speed of the air stream. Centrifugal forces acting on the airflow within the impeller blades accelerate the gas to a high velocity, expelling it in a steady flow.

Positive Displacement Blowers

Also known as rotary blowers, these machines use the concept of positive displacement to move air. They trap a definite volume of air then discharge or force it out against the system pressure. The rotary lobe blower and helical screw blower are two main types of positive displacement blowers.

Regenerative Blowers

Also referred to as ‘side channel blowers’ or ‘ring compressors’, these blowers take advantage of high-speed impellers to draw in air and ‘regenerate’ air molecules for higher pressure.

Axial Blowers

Operating similarly to axial fans, these blowers generate airflow by rotating a set of blades or propeller around an axis. They move air parallel to the shaft around which the blades rotate, making them effective for high flow, low-pressure applications.

What is the Compressor?

A compressor is a machine that takes in a certain quantity of gas or air and compresses it, thereby decreasing its volume and consequently increasing its pressure.

Types of Compressor

Compressors are a critical part of many industries, with different types being used based on their operational mechanisms.

Reciprocating Compressors

Also known as piston compressors, these are positive displacement machines. They use a piston within a cylinder to squeeze the air, thereby compressing it.

Rotary Screw Compressors

Rotary screw compressors utilize two meshed rotating positive-displacement helical screws to force the gas into a smaller space. They are known for their efficiency in mid to high levels of air pressure applications.

Centrifugal Compressors

A dynamic compressor that depends on the transfer of energy from a rotating impeller to the air. It is primarily used in high volume and continuous air flow applications.

Axial Compressors

Another type of dynamic compressor, it works by using rotating blades on an axis, which direct the flow of air parallel to the axis, compressing it as it moves through consecutive stages of rotating and stationary blades.

Rotary Vane Compressors

These feature vanes mounted on a rotor. As the rotor turns, the vanes slide in and out, trapping air and then compressing it as the rotation continues.

Scroll Compressors

These involve a fixed and orbiting scroll. Air gets trapped in the pockets between the scrolls and gets compressed. Especially used in HVACR industry due to their efficiencies and decreased noise pollution.

In addition, they can again be classified into categories such as:

Stationary or portable compressors
fixed speed or variable speed compressors
oil lubricated or oil-free compressors
electric or diesel compressors

Core Difference Between Blower and Compressor

In essence, the primary distinction between a blower and a compressor lies in the ratio of discharge pressure.

Blower

A blower is a device that increases the velocity of air or gas when it passes through it. It moves the air or gas, producing a substantial airflow, hence delivering a moderate to a somewhat significant increase in pressure.

They excel at moving large volumes of air or gas at moderate pressure levels.

Applications of blowers often include ventilation systems, drying systems, and cooling systems where a large volume of air movement at low pressure is desirable.

Their discharge pressure is comparatively lower compared to compressors. Blowers typically operate at less than 20 psi.

Compressor

A compressor is engineered to increase the pressure of air or gas. They operate by compressing air to higher pressure levels, making them suitable for applications that demand pressurized air or gas.

Compressors generally operate above 20 psi and can reach thousands of psi.

They extensive use in industries such as manufacturing, automotive, construction, and healthcare, where compressed air is essential for powering pneumatic tools, operating machinery, and facilitating industrial processes.

Now, the disparity is apparent:

blowers focus on generating high-volume airflow at low pressures, compressors are designed to elevate the pressure of air or gas to higher levels.

Operating Principles: Blower vs. Compressor

The operating principles of blowers and compressors may seem similar as they both deal with air or gas movement, but they perform markedly different tasks and work on entirely distinct principles.

Blower

A blower works on the principle of volume displacement. It takes in air at ambient conditions then expels it at a higher velocity, which leads to a slight increase in pressure.

It uses fan blades or impellers rotating within a casing to produce airflow. The air, guided by the casing, goes through the fan, increases in velocity and exits the unit. The devices typically create an airflow with a moderate surge in atmospheric pressure.

The blower’s operation involves minimal changes to the air, as it doesn’t compress the air but merely displaces it. This method of displacement means the blower will operate at relatively low pressures but with higher airflows.

Compressor

A compressor operates on the idea of ‘compression’. It not only outputs airflow but also changes its state by compressing it.

This process involves reducing the volume of the air or gas and thereby increasing the pressure significantly. There are several types of compressors, and each works a bit differently but adheres to the principle of pressure increase via volume reduction.

For example, in a reciprocating air compressor, the compressor takes in air into a chamber, the piston compresses the air, and then it is released into the system at a high pressure.

Rotatory screw compressors follow a similar principle but use rotating elements instead of a piston.

Efficiency and Energy Consumption

In the efficiency and energy consumption, both blowers and compressors have their specific benefits and considerations. Let’s delve into these aspects and understand how they operate.

Blower

The blower is generally more energy-efficient when it’s about moving large volumes of air at a lower pressure.

Since blowers don’t compact the air but merely displace it, they consume less energy for the same volume of air compared to compressors.

Their efficiency is further increased when they’re used for applications requiring continuous, rather than intermittent air movements such as in cooling and ventilation systems.

Compressor

The compressor is more efficient in systems requiring high pressure, despite their higher energy consumption.

They are designed to compress and thus condense air, which requires more energy. Compressors are thus ideally suitable for tasks requiring high pressure, such as fueling pneumatic tools, and air conditioning and refrigerating systems.

However, energy consumption in compressors can be optimized. for Instance, variable Speed Drive (VSD) compressors adjust their motor speed to align with the air demand, effectively reducing energy wastage.

Regular maintenance can also ensure maximum efficiency by identifying and rectifying potential issues like air leaks and inefficient operation before they escalate.

Maintenance and Service Requirements

Neglecting routine maintenance can lead to reduced performance, decreased efficiency, and eventually total failure.

Routine maintenance of blowers and compressors is almost the same, but compressors also require additional attention to the following aspects:

Replace Consumables

The consumables here include air filters, oil filters, oil separators, etc.

These air compressor spares must be cleaned or replaced regularly, primarily if the compressor operates in a dust-prone environment to avoid harming the compressor’s internal components.

System Pressure Checks

Monitoring the system pressure is advisable to guarantee the compressor doesn’t surpass its intended working pressure, which could be hazardous.

Lubrication

Oil-lubricated compressors require periodic oil changes. Synthetic oils often lengthen change intervals and can improve performance.

Preventing Overheating

Compressors generate considerable heat when in operation. The maintenance of heat exchangers may be your consideration.