Compressed Air Modulating Nozzles

At a Glance

Status

under development

Fuel type

electric

Sector

industrial

The RTF plans to incorporate this and othe compressed air measures into the next update of the Compressed Air Standard Protocol.

Decisions

Expand All Decisions

Latest decision

Decision details

Decided

May 22, 2018

Allocate resource to measure development

Decision Details

Allocate resources to developing the following measures:
- DHP for FAF with Optimized Controls
- Commercial and Industrial Fans
- Compressed Air Modulating Nozzles
Not allocate resources at this time to:
- CamfilAir Filter

Proposer Information

Name

Geoff Wickes

Organization

NEEA

Proposed Category

planning

Proposer Documents

ASU Preliminary Assessment Final.docx

ASU Preliminary Assessment Final.docx

Efficient CA Blowing Report.docx

Description

Air Saving Units (ASU) reduce compressed air consumption in blowing end uses by interrupting the flow of air at adjustable rates. ASUs controlled by a pilot pressure can operate at interruption frequencies up to 5 Hz, while electronically-controlled ASUs can operate up to 22 Hz. The theoretical advantage to this approach, as compared to flow-reducing devices based on continuous flow, is that each pulse of air is initiated at a slightly higher pressure than the pressure delivered in a continuous flow. This results in a rapid series of impulses that deliver a momentary increased impact to the target. The adjustability of the frequency and duty cycle (relative durations of ON and OFF flows within a pulse) of the pulses provides an opportunity to “tune” the ASU to the specific end use. Open blowing of compressed air is often used in industry and is nearly always a wasteful means of achieving some end. Examples would include the removal of dust or contaminants from a specific process or area; cooling parts that have been heated during the manufacturing process; drying parts that are wetted as a necessary part of manufacturing; to provide cooling air to employees or overheated bearings; to position parts along a production line; or to achieve numerous other specific effects. Reasons for employing open blowing usually include some combination of the following: • Lack of understanding of the cost of compressed air • Ignorance of more efficient means of achieving the desired effect • Ease of implementation • Staff that is unaware of its use in “inherited” systems ASUs save energy by interrupting, at adjustable frequencies, the flow of compressed air to blowing end uses. A mechanical advantage is provided in that a series of impulses is delivered to the end use rather than a steady stream of air. The impulses are delivered with somewhat greater force than a steady stream of air as the pressure in the ASU has an opportunity to recover during the OFF period of each cycle. The effect is similar to the slight “kick” that is felt when the spray head on a garden hose under pressure is first opened. That kick is due to the full pressure of the water starting to flow, but the pressure in the hose then drops quickly to as a steady stream develops. Each time the spray head is closed, the pressure rebuilds and the kick is felt the next time it is opened. The impulses delivered by the ASU are analogous to the spray head only the impulse delivery rate is much faster. Figure 1 shows the initial impulse for each valve opening as well as suggesting the independent settings of ON (flowing) time and OFF (no flow) time.