Purchasing a conveyor system can be a daunting task for an experienced buyer. It can be overwhelming for a new buyer. You need to provide some basic, yet critical information to get a quote. The principle that applies to this process is "The question you ask determines the answer you get." The more accurate the information, the more accurate the quote will be. Correct information from the outset will simplify the process and lessen the chance for misinformation down the line.
The first question to answer is what is the product to be handled. Surprisingly, this simple question is sometimes difficult to answer. In general, the conveyor system company needs to know the maximum and minimum dimensions for the products handled. Usually, this information is relayed in terms of composite dimensions, which means that largest and smallest dimensions in terms of length, width, height, and weight do not actually exist in one specific product. If possible, it's best to provide the actual dimensions of all the products conveyed and let the conveyor supplier discern the important data. Pay particular attention to the bottom surface of the product because that is the actual conveying surface. If there are protrusions from the bottom, that will change the type of conveyor quoted. Most conveyor suppliers will quote with a disclaimer that states that all products conveyed must have smooth, flat, conveyable bottoms. It is important to be aware that even a small protrusion can affect conveyability.
Rate of handling is the next piece of the conveyor specification puzzle. This information can be more difficult to obtain than the product data and is often misunderstood. The rate of handling is the number of units conveyed in a given period of time. For the most part, the important statistic for planning a conveyor system is the "peak" rate of handling. More often than not, this will be defined in "X" number of units per minute.
Many times, customers will state the handling rate based on an average rate over a shift or a day of production. The system may be required to handle spurts of production, which make the instantaneous or peak rate higher than the average rate. Although you average 35 miles per hour in your car, it must be capable of going 70 miles per hour for highway driving. The same is true for your conveyor system. It has to perform at the maximum rate. The rate of handling should include anticipated increase in production to meet future demands. Many times a customer will take the rate of the slowest piece of equipment on a production line and use that as the rate of handling. The overall rate will never exceed the rate of the slowest piece of equipment in a production line. Be careful not to overstate the rate dramatically because that will raise the cost of the equipment without giving a return of that investment.
What are you conveying and how fast are you conveying it will answer a lot of questions about your conveyor system. There are a few more items to consider. Are there environmental considerations to be taken into account? In this case, I am not speaking of the global environmental concerns but rather the location of the equipment. Temperature and moisture will have an effect on the conveyor and should be taken into account during the specification phase.
Obviously, if you are considering a conveyor system, there is some type of return on the investment. It could be labor savings, increased production, or improved product quality. When looking at your return, make sure that there is not one item creating a large percentage of your cost. Assume that 98% of your product is 36" wide or less and weighs less than 250 pounds. You have one seasonal item, which equals 2% of your production that is 48" wide and weighs 1500 pounds. That one item will result in a different class of conveyor and could make your investment increase by 50%. It may make more sense to handle that item separately from the conveyor system and thereby reducing the overall investment.
As a customer, the last piece of information required will be a result of self-analysis. While the conveyor supplier can tell you type of equipment you will need, he cannot tell you what your commitment to the equipment will be. Conveyor systems can range from being relatively simple to extremely complicated. I know that I have purchased electronic equipment because it has all types of functions that I never learned how to use. In retrospect, I didn't get a big bang for my buck. A conveyor system has to be maintained and requires an investment of time by the personnel that will operate the equipment. That investment of time is proportionate to the complexity of the system. The more functions, routing options, and sophisticated the control sequencing, the more the manpower investment will be for the system. Don't buy the complex system if you are not going to develop the expertise to understand and maintain it. In short, you can make the system too complicated for your work force to operate. Gauge what your commitment will be and purchase accordingly.
I hope this will you assist you when going to buy a conveyor. Oh, I left out the most important thing to do when purchasing a conveyor system. Call TKF!
Changing elevations on a conveying system is a common occurrence. The first thing to consider when deciding how to accompish the elevation change is to look at the product being handled. The length to height ratio of the product and the distribution of weight of the product will determine the angle of incline that can be used. Certain products such as pallets or alliances would require such a shallow grade that belt conveyors will not be practical. With other products that have a favorable length ratio, a belt conveyor may be the most economical means of conveyance. In general, a belt conveyor will convey at an angle, generally below 30 degrees for unit handling application, and will therefore take up more space than a vertical type of conveyor. The value of floor space should be considered when evaluating the economics of a belt conveyor.
If a belt conveyor is not suited for the application, there are several types of vertical conveyors that can be utilized. At this point, the next critical item to consider is rate of handling. For heavy loads, Vertical Reciprocating Conveyors (VRCs) are generally, the most economical and versatile. A VRC is essentially a conveyor that moves up and down like an elevator. The name comes from the up and down reciprocal motion of the conveyor. Usually, the VRC requires an up, and a down motion to deliver one load. Consequently, the conveyor is limited in terms of throughput. Because many types of conveyor beds can be used in a VRC, it will allow various flow patterns. It can convey to multiple levels, which makes it versatile.
For higher flow rates, a spiral conveyor may be considered. For relatively light handling with small package sizes, the spiral will handle the highest throughput of any of the vertical conveyors. Most of the manufacturers utilize plastic chains, so the overall width that can be handled is in the 27" range. Because there is no sequencing to feed the spiral, the product can be virtually touching, which allows a high flow rate. The spiral can be configured to allow for various flow patterns. There are rubber belt spirals, but in general they take up a lot of room and are quite expensive. Plastic belt spirals are typically a little more expensive and take up a more room than Continuous Vertical Conveyors. A spiral is a point A to point B type conveyor.
Continuous Vertical Conveyors (CVCs) come in several styles. There are flighted lifts which have flights connected to opposing chains that lift the product from a conveyor that is narrower than the product. The flights straddle the conveyor and lift the product from the infeeding conveyor. The product has to be near uniform in the width dimension due to the pick up arrangement. Product is usually pushed from the flights by means of a pneumatic pusher. Because of the pushing type discharge, multiple levels can be serviced by one unit, although pneumatic pushing can be viewed as a drawback, especially with fragile product. Another continuous lift is a pendant style lift which has a carrier suspended from parallel chains that move in a pattern similar to an oblong ferris wheel. Generally, the discharge conveyor allows the carrier to pass through while capturing the product. Multiple levels and flow patterns can be serviced by pivoting the discharge conveyor out of the way when that point is not the destination and in the path when it is the destination. This unit is difficult to maintain, but its flexibility make it a possible solution for multi-level picking operations in a distribution center.
The final type of continuous vertical lift is the four-strand chain style. This conveyor has platforms attached to four chains. The platform has a locking block which allows it to flex in one direction when returning and be rigid in the opposite direction when conveying product. This type of conveyor is only available in a "Z" flow and services only one (1) infeed point and one (1) discharge point. (Some manufacturers make a "C" configuration of this lift, but I have only heard maintenance horror stories about them.) This unit can handle up to forty loads a minute. It takes up less room and costs slightly less than the plastic belt spiral.
That is a brief overview of the options for vertical conveyors. I know I didn't touch on all the options. The best course of action is to call me with the specifics of your operation and I will steer you in the right direction.
I now feel that I am truly a man of the new millennium. I am writing my first blog. That felt good. See ya next time. Oh, it needs to be a little longer and have a semblance of substance, you say. This may be harder than I thought when I agreed to this. I could write some cutting edge information about conveyors. Considering I just sell the stuff, people would probably realize that I don't actually know anything about conveyors. Maybe I should just wing it and throw out some topics and see if anything sticks.
Speaking of the new millennium, there was talk of me getting a Facebook page. I don't really know what it is, but I know I want it. I asked my daughter to be my friend on Facebook (I think that's what they call it), she politely told me "no". Actually, she asked me if I was as stupid as my question. I wonder if Facebook is actually just more technologically advanced vehicle for me to face rejection. When I was younger, I had a blind date with a girl named Louise. I walked up to a young lady and said "Are you Louise?" She asked "Are you Jim?" I said yes. She said, "I'm not Louise." If you don't know Rodney Dangerfield, then I made that joke up. If you do, then please be quiet to the other guys.
I guess that despite the blog, I ‘m not really a new millennium kind of guy. I suppose I could talk about the things that I know well. I don't think sitting on the couch and watching sporting events gives me a unique perspective. So much for that idea.
Maybe I should start by introducing myself. My name is Jim Walsh. I am the Vice President of Sales for TKF, Inc. As you have already surmised since I am writing this blog, I am a new millennium kind of guy. Here are some topics for future blogs:
Acronyms - Friend or Foe. Sure, they shorten things, but they can darn confusing.
Vertical conveying options - Actual topic with value. (I'll probably get a ghost blogger for this one.)
VFDs - Are they over-specified and when are they necessary?
Accumulation - Zero-pressure versus minimum pressure.
Overhead Power & Free Conveyor - Not just for the big factory?
If either of the two readers of this blog have any items that they wish me to comment on, please forward them to me. It can be anything. I am in sales, so having knowledge about a topic has never been a prerequisite for comment.