When you're in production around the clock, you need a compressor with 24-hour dependability: the QSI. When Quincy began building rotary screw compressors over a quarter of a century ago, they knew that they would be a primary power source for their customers. In fact, they knew that a customer's ability to run a plant at full capacity might well depend on the performance and reliability of their products.

With that in mind, they set out to build the most reliable rotary screw compressor on the market. They called it the QSI, and it soon became the compressor of choice among those who value quality. Today a number of those original QSIs are still in service, because everything Quincy did in the design and manufacture of those first QSI machines took quality a step beyond the existing standards. Quincy is still dedicated to maintaining its reputation as the quality leader.

Quincy checks the quality of each rotor with the only polar coordinate measuring machine in use at a U.S. compressor manufacturer. All static parts are checked prior to final assembly by precisely calibrated coordinate measuring equipment in their Quality Assurance Department. Every machining process is checked, with no detail overlooked.

Quality is never easy: it's an arduous, time-consuming proposition that requires serious dedication. But as long as our customers depend on us for tough, reliable compressors, quality will always be the watchword at Quincy. It's the one big reason why Quincy compressors are undeniably the world's finest.

QSI Features & Amenities

• Airend - The QSI airend is the heart of the compressor package. Its design and manufacture are critical to reliable, efficient operation. Quincy packs more high quality features into this airend than any other manufacturer.
• Shaft seal - Quincy has developed a shaft seal arrangement with unmatched reliability. Quincy uses a triple lip seal design as the primary shaft seal, with a single lip outboard providing the final seal to the exterior. Should any lubricant pass the triple lip seal, it would collect in a cavity between the seals and be scavenged back to the airend.
• Triplex bearings - The typical bearing arrangement for compressors of this class is a duplex arrangement. The QSI design gives you a minimum of 130,000 hours with a superior "third bearing" arrangement. This provides 30-100% more life than competitive machines.
• Axial flow inlet housing - Quincy has found that axial flow inlet improves compressor efficiency by 5 -7% over traditional radial flow designs. This allows the QSI compressor to deliver the same amount of air as the competitors, using 5-7% less power. Housings on 245-750 models also have an integrally cast flange to directly connect the airend to the drive motor. This design eliminates any chance of coupling misalignment.
• Positive lubrication system - Quincy compressor uses a positive displacement, gear type lubricant pump to assure proper lubrication to the rotors and bearings. This pump is directly driven off the rotor shaft, so lubrication is assured as soon as the compressor starts. The pump also provides proper lubrication during periods of unloaded operation. This pump, in combination with our precision machined inlet valve, allows our machines to release reservoir pressure and cut unloaded BHP to 15 percent or less, the lowest in the industry. This is significantly better than most competitive machines, which must maintain internal pressure for proper lubrication, thus resulting in power costs running from 35-45 percent of full load BHP requirements.
• Asymmetrical rotor design - Quincy's rotor profiles are designed to deliver the maximum air flow using the minimum horsepower. Years of profile development have yielded efficiency improvements of better than 20% over our first designs. Profile design, however, is not the only factor in compressor efficiency. No other compressor manufacturer holds tighter manufacturing tolerances than Quincy. Quincy is the only rotary screw compressor company in the United States that uses a polar coordinate measuring machine to ensure that every rotor measures up to our standard of excellence.
• Oversized heavy-duty air filter - QSI compressors come standard with inlet filters other manufacturers sell as optional equipment. Our filters are sized to handle capacities well in excess of the compressor requirements.
• Nema frame motors - Quincy's QSI packages are designed to use NEMA frame motors in a variety of voltage and enclosure configurations. No "special" of "proprietary" motors are used on any QSI compressor. While proprietary motors may cost less initially, Quincy knows that this approach lacks the simple serviceability that reliable NEMA frame motors provide.

Above, we have reviewed the features that give you the most efficient design, including axial inlet, lubricant pump, highly efficient rotor profiles, and tight machining tolerances. To take advantage of the QSI's built-in-efficiency under a wide range of operating conditions, Quincy offers a full range of control modes.

Capacity control for the QSI line is handled through a full-range modulating inlet valve. This valve matches compressor output to system demand. The capacity range over which the valve operates is fully adjustable, allowing the compressor operation to be matched to system demands for the most efficient use of energy.

A selector switch on the control panel allows the user to select auto-dual control or continuous run control. in the auto-dual mode, the compressor will load, unload, and modulate in response to system demand. If there is no system demand for the pre-set time delay, the compressor will shut down the main drive motor and, on air-cooled units, the fan motor. The compressor then goes into a "standby" mode and continues to monitor system pressure. As soon as the system pressure drops, the controls will react by restarting the compressor.

Continuous run operation can be selected if typical plant operations include frequent, brief periods of no air usage. In continuous run, the control circuitry bypasses the timer and the compressor does not shut down. This control method prevents excessive restarting and extends the motor life in certain applications.

The compressor control panel has a maintenance and shut down annunciator panel to indicate various service and shutdown conditions. A graphic display showing the compressor schematic has amber lights to indicate the need to service the air filter, lubricant filter, and separator element. Red lights indicate shutdown conditions for high air or lubricant temperature, and drive or fan motor overload. These indicators are designed to allow easy remote sensing of all service and shutdown conditions. The control panel also includes:

• Start button
• Red mushroom stop button with twist lock
• Power-on light
• Lamp test button for annunciator panel
• Discharge air pressure gauge
• Percent capacity gauge
• Hour meter
• Compressor discharge temperature gauge

All gauges are 2 1/2", stainless steel backed and beveled, with silicon dampened dashpot movements. They provide the reliability and service life of liquid-filled gauges, without the possibility of liquid leaks. Temperature and pressure gauges have both English and metric scales.

Outstanding Package Features Ensure 24-Hour Reliability

• Low noise. Quincy QSI compressors have the lowest noise level of any non-cabineted compressor in their class. Two cabinet options offer even lower noise-as low as 73dba.
• Low fluid carryover. Quincy's separator design and engineered fluids combine to produce fluid make-up rates of less than 3 PPM and downstream carryover rates of 1 PPM or less.
• Easy serviceability. All normal maintenance items are conveniently located at one end of the machine for easy serviceability.
• High-efficiency fluid filter. Quincy uses a 10-micron absolute fluid filter with a special micro-fiberglass media to provide the best protection for the airend and bearings.
• Oversized aftercoolers. The QSI line of compressors uses aftercoolers with a 3-5 degree approach at standard conditions. This means more moisture is removed by the aftercooler, improving dryer efficiency.
• UL-approved electrical controls. all Quincy compressor electrical controls are designed, inspected, and approved to UL and NEC specifications.

Sae O-Ring Fittings

We've designed the QSI with far fewer potential leak points than other compressors in its class. One such feature is the use of castings in place of discharge piping; another is the use of SAE O-ring fittings on all lubricant pipe joints over 1/4" in diameter. These connections boast a superior design to standard pipe fittings, and are used extensively for trouble-free installation and operation in the hydraulic and fluid power industries.

When you're in production around the clock, you need a compressor with 24-hour dependability: the QSI. When Quincy began building rotary screw compressors over a quarter of a century ago, they knew that they would be a primary power source for their customers. In fact, they knew that a customer's ability to run a plant at full capacity might well depend on the performance and reliability of their products. Please review the Quincy QSI product brochure by clicking here (1MB PDF file) and contact the sales team at Air Perfection Inc. should you have any questions. Click here to visit our sales department online.