A Guide To Diesel Rotary Screw Air Compressors

May 28, 2021

D60 Diesel Driven Air Compressor

What Is A Diesel Rotary Screw Air Compressor?

A diesel rotary screw air compressor is an air compressor fueled by diesel that uses rotors to compress air. Diesel air compressors allow operators to generate compressed air on demand for powering tools and equipment.

How Does A Diesel Rotary Screw Air Compressor Work?

A diesel air compressor uses a small engine to convert diesel fuel into mechanical power and then converts that mechanical power into air power.

Like all diesel engines, the diesel engines found in rotary screw air compressors are internal combustion engines. They combine air, fuel, and lubrication in high-pressure cylinders, forcing the mixture to combust, which moves the engine’s pistons.

This mechanical movement forces the rotors (AKA rotary screws) to move, which compresses the air. This air is circulated through the system, along with lubricating oil, passing through various filters and coolers, before it is ready for use.

To learn more about the intricacies, read VMAC’s article: How Does A Diesel Driven Air Compressor Work?

What Are The Benefits Of Diesel Air Compressors?

There are numerous benefits to diesel air compressors, including:

Diesel Rotary Screw Air Compressor Same Fuel Type: Operators who already have a diesel truck will save time at the pump if they match their fuel type. Some diesel air compressors, such as VMAC’s D60, can even be plumbed right into the vehicle’s fuel tank, making fill-ups a breeze.

Fuel Efficiency: While diesel and gasoline costs are often similar per gallon, diesel is approximately 25% more efficient to burn. That means the same amount of fuel goes a lot farther between fill-ups. A diesel rotary screw air compressor can be a smart choice for operators concerned with fuel costs.

Easy To Move: Diesel rotary screw air compressors are mounted on the truck’s deck, making them easy to move between trucks if operators upgrade their vehicle. Alternatively, operators can use a skid-mounted or wheel-mounted diesel air compressor, which easily moves around a job site.

High Flashpoint: The high flashpoint of diesel makes it a safer option than gasoline in environments where sparks frequently occur.

Reliable Engines: Diesel engines have a reputation for being hardy, and small diesel engines, like those used in rotary screw air compressors, are no exception. Operators who want an air compressor backed by a reliable small engine may favor diesel rotary screw air compressors.

What Are The Benefits of Rotary Screw Air Compressors?

Rotary screw isn’t the only type of diesel air compressor available, but it is the superior option for mobile applications. When compared to reciprocating air compressors, there are numerous benefits:

100% Duty Cycle: Rotary screw air compressors run at 100% duty cycle, while most reciprocating air compressors can only run at 20 to 30% duty cycle. That means for every 100 seconds a recip air compressor runs, it’s only supplying full power for 20 to 30 seconds. Some 2-stage reciprocating air compressors can run at 100% duty cycle, but even these will eventually run out of air in the tank because they produce less power than the tools use. Because of these shortcomings, operators with reciprocating air compressors need to purchase bulky air receiver tanks to store extra compressed air and pick up the slack.

Longer Lifespan: Rotary screw air compressors are built to last. In a mobile setting, manufacturers like VMAC guarantee the rotary screw will outlast the life of your truck (with proper servicing). Meanwhile, reciprocating air compressors are known to break down and require more routine replacement.

VMAC's first rotors

More CFM: Rotary screw air compressors are also powerful, providing more CFM per HP than reciprocating air compressors; this means a smaller air compressor can provide higher outputs, saving weight and space on vehicles. Quieter: Reciprocating air compressors tend to be loud, especially compared to most rotary screw air compressors.

Energy Efficient: Rotary screw air compressors are more energy efficient. Operators can save on fuel and trips to the gas station by choosing a rotary screw model.

With so many benefits, why would anyone choose a reciprocating air compressor? First, they have a lower upfront cost, so they require a smaller capital investment. A reciprocating air compressor can be a logical short-term choice for budget-strapped buyers.

The second reason people choose reciprocating air compressors is that they can do many of the repairs themselves. Rotary screw air compressors are more complex machines and require qualified service technicians if they break. However, a rotary screw air compressor that is properly maintained should not require skilled service repair work.

Tools Frequently Powered By Diesel Air Compressors

impact-gun-tire-changeNumerous applications use diesel air compressors to power their air tools. The most common air tools powered by diesel air compressors include:

  • Jackhammers
  • Impact wrenches
  • Tire inflation tools
  • Grinders
  • Sanders
  • Chipping hammers
  • Backfill tampers

When Should I Consider A Diesel Rotary Screw Air Compressor?

Operators who already have diesel trucks or equipment should consider diesel rotary screw air compressors. Vehicle-mounted options are a great fit for mobile heavy-duty mechanics, mobile tire service technicians, and 24/7 roadside repair technicians. Meanwhile, skid-mounted or wheel-mounted diesel air compressors are a solid option for remote job sites

Additional Diesel Air Compressor Resources