Low-Pressure Air Compressors

The difference comes down to operating pressure and the cost to get there. High-pressure compressors are built for applications such as pneumatic tools or general shop air that require 100 PSIG or more. Low-pressure compressors are built for applications that only need 25 to 45 PSIG, such as pneumatic conveying or aeration. Running a high-pressure air compressor and reducing the output with a regulator wastes the power spent compressing air past the pressure the process actually needs.

Low-pressure screw compressors offer several practical advantages over both high-pressure compressors and conventional blowers:

• They produce more airflow per horsepower than a high air pressure compressor of the same size because less energy is spent on compression.
• They put less stress on downstream components, hoses, and fittings that aren’t rated for high pressure.
• A screw airend delivers steadier, more controlled airflow than a blower, without the surging that can accompany demand changes.
• Variable-discharge port models adjust their internal compression ratio to match actual demand rather than running at a fixed setting.

Low-pressure air compressors supply various industries that need high airflow at a modest operating pressure, rather than standard shop air. Common examples include pneumatic conveying of bulk materials, wastewater treatment aeration, food and beverage processing and general manufacturing lines that use low-pressure air for cooling, drying, or material handling.

No. The KRSL is an oil-flooded rotary screw compressor that uses oil injection in the airend for cooling and sealing, along with a three-stage oil separation system to keep carryover below 3 ppm. If your application requires oil-free air, ask our team about Canex’s oil-free compressor options instead.

Yes. An undersized compressor runs at full load continuously and struggles to keep up with demand, while an oversized compressor cycles on and off more than it should, wasting energy and adding wear on components. This matters even more in intermittent-use applications, where demand can shift from a steady flow to a burst lasting a few seconds and back. Matching your compressor’s capacity to your facility’s actual demand curve helps keep operating costs down and extend equipment life.

Compressing air requires more power consumption the higher the pressure ratio, so a compressor pushing air to 100 PSIG and then regulating it down to 25 to 45 PSIG spends energy on compression that the process never uses. A low-pressure compressor with a variable discharge port, like the KRSL, produces air only at the pressure the job requires, so that wasted compression work is never done in the first place. The effect compounds with pressure: in an application like wastewater aeration, every 2 PSIG above the process requirement adds roughly 1% to energy consumption, so running a system that’s over-pressured by even 20 or 30 PSIG adds up over a year of continuous operation.