Buyer's Tips - The Basic Stuff
Here's the minimum stuff you'll need to cover to make a buy decision.
If you've purchased an industrial vac system before, you need not read this particular page; it's basic stuff.
A machine's duty cycle is determined by how long it is to be operating. It is imperative to match the capability of the vacuum system you purchase to the expected duty cycle.
In general, most small shop-type or canister vacs use high speed (20-25,000 rpm!) vacuum producers that wear out their bearings or carbon brushes in as little as 800 hours. Some of the better European models can get 2,500 hours, but they're costly.
This means that if used just 3 hours per day, a standard canister vacuum will not likely get past 18 months.
Most vacuum systems on the market over 5 Hp use motors that will run continuously for years. There are differences in the types of vacuum producers that make a difference to how long they'll last. Some last 5 years, some last 40. This is fully discussed in our Central Vac section, in Types of Exhausters.
For systems smaller than 5 Hp, make sure that you get something that won't self-destruct if you want your system to last.
The Filter System
Probably no other part of a vac system gets so little attention at first and so much attention after! You're probably even reading this because of the incredible time being wasted with the filters on an existing system.
The filter is a system: you must select among several different types of filter media based on how fine the dust is you're working with.
You'll need to consider how the filter system is cleaned. Most filters on portable units are "shaker type". For some (especially canister types) this means removing the filter and shaking it!
For the larger systems with shakers, there are a number of methods out there, but beware that side-to-side shaking is more effective than up-down shaking, but it's also harder to do. Some cleaning systems out there are pretty useless, others are great. Ask to get it explained in detail.
The shaker type filters need to have the system turned OFF in order to clean the bags. So, unless the filters remain efficient until the material canister fills, the system will need to be turned off and the filters cleaned periodically. This is the single biggest cause of complaint and frustration that users have with undersized "shaker type" filter systems (and the biggest cause of lost time).
The cleaning system may be automatic - either by using an "automatic shut down - shake - and restart" feature, or by using "pulse jet" cleaning, or by using "reverse air".
Only one portable we know of still uses reverse air, and it's not automatic. It is an older technology, but remains effective in some systems.
Pulse jet cleaning is a dust collector technology that enables filter cleaning while the system is still running. On-line cleaning is not as useful as it seems for a system with limited storage capacity and it requires connection to plant air!
Most of the time pulse cleaning systems are reserved for use in portables with cartridge type filter systems. This is because these filters clog easily and must be cleaned often. Many cartridge units claim pulse cleaning, but are misleading in that it is not continuous; the system must be shut down , connected to plant air, and manually pulse cleaned.
In our opinion, if you have very fine dust, steer clear of cartridge systems. Or at least get user references - some cartridge systems out there work well, but many don't. Some manufacturer's even make you take the cartridge out to clean it any way you can.
You should be aware of the "can velocity" - the upward flow of air through a filter canister shouldn't exceed 125 fpm, or you need to ask why it works. If the can velocity is too high, the filters will get clogged too quickly , and/or won't be easily cleaned.
Clearly, you will have to decide how much material storage you can easily handle. If the material is steel shot at 375 pcf, then even a very small container will need to be handled by machine. If the material is paper "fluff" at 5 pcf, you need to ask how to compress this material.
There are numerous equipment standards and optional equipment to handle the different materials. Ask several different manufacturers for their ideas.
Portable machines need to be easily moved. Large wheels push more easily over rough plant floors (and mats, and cables) than do systems with small wheels. You may require that the unit to be moved around the plant by forklift. Or you may have an overhead crane that would be useful.
The system you chose must be easily handled within your plant layout. If it must go through doors and narrow aisles or go into elevators, better check the dimensions and weight.
Then check for material gauge and how robustly the unit is constructed. The system is going out into the war-zone, so if you want it to last it had better be built like a tank!
Generally, any system over 2 Hp will use 3 phase power. You will need distributed power sources throughout the area you want to cover. If it is not in place, you will need to budget for this. Be sure that the connection points each have disconnects, because rarely do portables feature disconnects (under 20 Hp anyway).
Finally, consider the electrical type you need. Many plants require a dust tight electrical enclosure (NEMA 4), but most portables offer only NEMA 1 or 12 (general duty, not sealed) as standard.
Finally, you'll need to consider things like delivery, delivery cost, and warranty. Look at the warranty carefully. Does it cover shipping of replacement parts, or labor? What exactly does it cover and how? You'll be amazed at the different levels of after sales service!
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DuroVac Industrial Vacuums
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1- 888- 330- 3365
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