Multi Operator Central Vacuum Systems

Multi-Operator Central Vacuum System Overview

Central vacuum cleaning systems that support more than one operator usually use a "dynamic" type of vacuum producer.

These machines maintain an equal vacuum while the air volume changes, with horsepower increasing with flow.  To the operator, this means performance doesn't change as the number of operators change.

Normally, the size of hose used is less than 2.5" ID and less than 50 feet long.

Central vacuum systems are made up of six major components: the vacuum producer or exhauster; the filtration system; the discharge device; the conveying or piping network; the hose and tools; and the control system.

All the above must be selected to work specifically for your application.  No two systems will be the same, so each must be engineered individually.  If you have an application in mind, please contact us..

The Vacuum Producer

For many applications, we use HSI multi-stage centrifugal exhausters.  These are tough-as-nails, cast iron exhausters that will still be running when you and I retire.

Note particularly the inline filter (the can closest to the motor - the other one's a silencer).  This protects the exhauster and operators against filter failure - and should NOT be considered optional in our opinion. 

HSI centrifugal exhausters range in size up to 25,000 icfm for vacuum levels under 13" Hg.   They provide for clean, dry, pulsation free flow at relatively low noise levels.

The Filtration System

We design and fabricate filter separators to suit your specific application.  While most dry powder systems will incorporate a QLP type pulse jet filter, there are separators designed to handle liquids, or abrasive, or explosive materials.

Filtration must be designed as a "system".  The type and characteristics of the material is important, of course; but we also need to know what you want to do with the material.

If the material is to be continuously discharged back to process, no internal material storage is required.

If the material is to be stored within the system, and batch discharged with the system shut down, a certain storage capacity is required.  Note please that the storage internal should be slightly LESS than the intended receiver hopper, or you'll get a nasty overflow.

The Discharge Device

Discharge valves are an often overlooked component, but in our (humble) opinion, one of the most important!

Many systems are specified with a standard 8" gate valve for batch discharge.  But a huge number of materials will "bridge" over a little valve.

Most materials that bridge are better continuously discharged through a rotary air lock valve like the one shown on the left.  If the material is abrasive, a "flapgate" type valve is preferred.

For batch discharge systems, an oversized valve will always be helpful.  A vacuum cleaning system will always suck in material that isn't "specified".  No other component in the system has the potential to waste more maintenance time!  We make our valve recommendations based on long term reliable performance, NOT price.

The Piping Network

A well designed pipe network MUST take into account the minimum number of operators expected to use the system.

It's easy to design a vacuum system for the maximum number of operators using the system.  Any dust collector designer can do that, and all the published "How To" booklets out there will let you design a system also.

However, it's not nearly so easy to design a pipe system to accommodate a variable number of users, and ensure material conveys back to the separator.  

A centrifugal exhauster changes its air flow based on demand, so if a 6" pipe requires 600 scfm to convey materials, and the number of operators changes to drop the air flow below 600, how do you prevent plugging of the system?  Best to call, and we'll show you.  There are lots of tricks.

Conveying networks may be specified as O.D. tubing and fittings (the most common for multi-operator systems).  Schedule 40 and 80 piping is more common for loading systems.  Bends are usually long radius type.

The system may be joined together with "shrink sleeves" or with bolted compression couplings.  All systems take into account static conductivity.

The Hose and Tools

Hose and tools must be lightweight, yet be of a robust, industrial duty design.  There are hundreds of types out there, but we've managed to pare down to a selection of the best.