Since it hasn’t been introduced you could suppose that the drainage tile customers don’t value some of the benefits that would be gained by using a drainage pipe with a smooth inside such as:

• higher flow capacity given the better Mannnings N flow coeffeicient for a smooth wall pipe
  

  Sample of coilable smoothwall corrugated pipe

• longer runs without increasing the diameter
• possibility to use a lower slope
• better internal cleansing / flushing
• reduced fuel consumption given the possible downsizing of mains.
• Higher equipment usage with the possible extension of runs.

When looking at the above list there seem to be too many benefits to the end user for this product not to enter the market. So one can conclude the barrier to entry must be a technology barrier, with the drainage tile manufacturers not having the appropriate technology to make the product in North America.

In my next posting I’ll talk about some of the requirements that the technology to make coilable corrugated pipe must have to be higly efficient and compete with the low cost 4″ corrugated pipe.

If you have questions about how to make corrugated doublewall pipe in coils you can check out my corrugated pipe technology page and then send us a question, we’ll be happy to get you more information.

Corrugated pipe scrap reduction machine

As corrugated pipe production has gotten larger and larger in diameter it has become a nuisance in the plant to deal with the scrap that can be produced during start up. In pipe diameters ranging from 24″ – 60″ it becomes more and more expensive to buy a huge grinder to deal with large pipe pieces. Why not chunk it down into smaller rectangles and use a lower horsepower grinder?

The traditional way to handle the corrugated pipe is to bisect into quarters, or sometimes eighths in shorter pieces of 4′ – 5′ in length. Most of this work is done on a sawzall. I’ve been to a few start-ups that we considered quite efficient, but even in these situations the staff can have 30 – 40 feet of pipe to cut up and put in the grinder. When your dealing with 60″ pipe this can be an ominous task, and a few pounds as well. The last thing you want is for the pipe to go in the yard to be cut later, get dirty and contaminate your regrind stream when it eventually does get cut and ground.

As you start to run your plant with shorter production runs – a typical strategy to reduce inventory and increase flexibility to make products the customer wants – then your start-up scrap becomes a more frequent occurrence.

The machine from Adescor isn’t a shredder, or fancy device to reduce the pipe into small granular pieces. Its a good old fashioned simple shear that chunks the pipe into approximately 6″ by 18″ pieces, and does this automatically on pipe lengths of about 5′.  A typical  length the guys will cut during start up to check the inside of the pipe before they run it through the downstream equipment.

The machine works well, and is already proving very popular with the guys in the plant. For the owners, you get the scrap cut up much quicker, back into regrind and into the extruder with less contamination. For more information on the Adescor corrugated pipe scrap reduction system please get in touch with us at Profilepipe Machinery or send us an inquiry from this site.

TK

So ,what have I noticed after the past 21 years going to the K?

If you are looking to buy a machine that makes corrugated pipe, the mechanical technology hasn’t changed much. You have vertically oriented corrugators, and horizontal table top styles. These two designs can be dated back to Fraenkishe making the design in the table top horizontal configuration and then Reifenhauser, making the first vettically oriented machine. 

Each has particular benefits in certain customer situations. You can also make this comparison about air cooled Vs. water cooled, both work, and work well if the proper climate exists, or the investment to make the proper climate is made by the customer.

 This is also the challenge about how long a corrugator you buy? Should you buy a machine that is set up for 5 years down the road in output? A much bigger investment, or should you start with a lower capacity machine with the ability to extend in the future? Why not ask this to the guys who are trying to sell you their great technology? What is the upgrade potential? Let them help you make the money to buy the fastest technology.

So, come back in a couple weeks, I’ll have a few more points on what you need to be looking for if you’re ready to buy a corrugator. As a point to all, you should be doing a credit check on all the corrugator suppliers before you give them any of your money! Rumours are rampant in the industry about one of the majors running out of cash.

When you consider the amount of heat we take out of the pipe after extrusion, you have to believe there is a use for it.

Their is the obvious technology of using waste hot air or water to preheat the resin entering the extrusion process, this is simple and has been done for years. What I am trying to find is a technology that turns our waste heat into a mechanical energy.

I have come across information on the Stirling engine. This is a technology that generates mechanical energy from low temperature heat sources, and has been known for over a century. What I haven’t been able to find is a company that has developed this technology around waste heat temperatures in the 90 – 120 F range.

I also wonder why the chiller technologies have not been developed for a reverse process to cooling. I have read that it is possible to use low temperature waste heat to drive a compressor, and as such you could drive a generator set to produce electricity, recycling it back into the plant. It seems so simple, but so far I haven’t found any suppliers.

So, this is a topic I am really interested in, but have had great difficulty finding information. If you have some direction for me, or can add some ideas to recycling heat in an extrusion plant I would be excited to read your comments.

Unicor UC1800 corrugator

In it they discuss their fall agents meeting in Bamberg, an article on their high speed UC125 corrugator for the production of cable protection pipe, and another article on their UC1800 for the production of large sewer pipe.

Unicor continue to offer inovative solutions for their customers with a dedication to machinery development that some would say is unsurpassed  by their competitors.

If you have specific questions about the articles in the Unicor newsletter and are located in North America get in touch with me.

Corma HSC series 2 perforator

I first became aware of the Valley Gear slotting perforator in the late 90’s which had a slotter spindle retraction system allowing an in-line coupler to pass by the cutting heads without the bell itself being perforated.

I am aware Valley Gear have a number of US patents on their perforators that deal with many of the mechanics that would be similar to the design Corma are promoting to have invented.

You can view these patents for yourself by going to any of the numerous patent search sites and looking up any of the following patents.

 If you are looking at the Corma HSC Series 2 perforator ask the hard questions of Corma about the state of existing patents governing the design. As a buyer I would definetly want their guarantee that the design is free from infringing other patents, and I would ask them to indemnify me from harm if as a user I was drawn into patent litigation.

If you find this topic interesting, or better still have some comments about the subject please take the time to add a comment and I’ll get it on the blog in quick time.

Beware on this design.

When talking to users of automatic coilers, the most common long term problem becomes repeatability of the strapping head. The strapping operation on a pipe coiler is a high duty operation with many variables that can change over time. The strapping head is also the most complicated electro-mechanical component on a pipe coiler, with many small precision components, numerous sensors, and high speed actuations.

Automatic pipe coiler for corrugated pipe

So, does this mean automatic pipe coilers are a bad thing? Not at all. What it means is you really need to evaluate the strapping component of the machine, understand how it operates, and ask lots of questions of your supplier.

Some of the obvious questions:

1. What are the wear parts, and ask for pricing of these.
2. Are the common purchased items: sensors, gears, bearings, off the shelf items with any of your local industrial suppliers.
3. What is the sensitivity of the machine to various types of strapping.
4. How does the strap feed and accumulator system work?
5. What is the repeatability of the strapping cycle out of 1,000 cycles.
6. How are the strap races manufactured, and can they easily be maintained for smooth, obstruction free operation.

 A focus on the strapping head is one of the most important reviews you can make when evaluating automatic pipe coiling. Ask your vendor for references, and make sure you call them.

There are also opportunities for retrofitting and improving an existing machine. While this tends to be complicated, it’s not impossible, and can be very worthwhile. If you have significant up time opportunity take a hard look at it.

For more discussion on how the strapping system between machines compare, get in touch with me at Profile Pipe Coiler or ask a question in this blog article.

TK

The guys making this video were very creative using the ubiquitous 4″ corrugated pipe in their mini movie “The Idol of Jinnea” You can find the video clip at about 3:30 into their movie.

This vyes with some of the Christmas reindeer we have become used to seeing, or the many other seasonal decorations we see corrugated pipe turned into.

Sorry for the break from my typical technical discussion, but I had to smile when I came across this.

TK

Cross section of a corrugated Pipe that was low pressure injection molded with a PE foamed material in a pipe corrugator

I can think of many products that would benefit from a continuous extrusion process: architectural trim, corner molding, foam pool noodles (imagine a snake design for your kids), possibly even specially profiled gasket designs with indents and detents not suitable for traditional profile extrusion.

Pipe corrugators when fitted with molds can many make shapes suited for a straight open close mold mechanics, it is even possible to fit molds with special inserts that can be retracted prior to opening.

Pipe corrugators by their name pigeon hole themselves into a very narrow technology niche, rename them and a pipe corrugator is a very sophisticated continuous extrusion takeoff system capable of moving molds past a fixed injection point, at high speed, with great precision while supplying vacuum to the mold cavity for even filling with very controllable cooling or heating systems.

Over the past 40 years pipe corrugators have evolved in the light weight profile walled pipe extrusion industry with tremendous mechanical advances from the traditional vertical chain carrier air cooled style machines. Today very high speed liquid cooled or heated molding systems are available and could easily be adapted into a multitude of possible continuous extrusion or continuous filling applications.

Low pressure injection molding on a pipe corrugator has already been proven by manufacturing solid PVC ribbed pipe.

With rapid development of the composite extrusion industry, more conversion of traditional building materials, the penetration of foaming technology into the extrusion industry it seems imminent that development groups will be looking for more advanced systems to perform high speed continuous mold filling of infinite length products.

So, what would one look for if evaluating a product application for a continuous injection molding extrusion process.

• How does the material flow, does it pour or extrude. Material with low viscosity at exit of the injection nozzle are likely best run in a vertical process using gravity to their favor. Materials with high viscosity are likely to handle the more typical horizontal extrusion filling orientation.
• What is the mold cooling or curing temperature needed. Molds typically are cooled, and water cooling systems are well proven and advanced. Heating systems, which are really higher temperature operating curing systems are also available, but more expensive due to the oil heat transfer system used.
• What is the tolerance in the product design for flashing? As a general rule, the less tolerance for flashing, the more expensive the machinery. The function of the mold mechanics requires mold halves in repeating increments typically called the mold length. This characteristic of the extrusion filling process requires thorough evaluation of not only the product design, but the capabilities of the machinery, and the ongoing maintenance to maintain the required flashing specification.
• How does the technology manage thermal expansion and contraction of the mold set? This is a critical component of setup and efficiency. When a mold train running in an endless loop changes in length from thermal expansion or contraction it affects the drive gear train, it’s important to review how this is accommodated in the machine design.
• Can the continuous extrusion device be easily changed in mold train length? In many applications a discreet part will be made and later cut, when dealing with a continuous mold train of a fixed length you must design the discrete part length to result in an integer quotient when divided into mold train length. This relationship should always result in a review of the finest gear pitch increment that the mold train is driven by. Resulting in the possible mold length variations for part design.
• What is the line speed you can get to. In the corrugated pipe industry line speeds approaching 200’/min have been talked about. In the 4” corrugated drainage tubing technology line speeds of 120’/min are known. In the end the line speed is governed by the contact time the product needs to cool or heat prior to release from the mold. Continuous extrusion technology for pipe corrugating has been made with a mold – product contact distance from 12” to as long as 20’, it very quickly becomes a ROI calculation.
• Are changeovers important? If it’s a one product line likely not, but with the outputs of this technology that’s unlikely. A complicated area to discuss, but intuitively the faster you can change a line the more money you can make. Make sure you understand the complete changeover process: die, molds alignment, height adjustment.

An advanced takeoff system allowing continuous vacuum forming at high speeds under tight temperature control is highly developed in the pipe industry. I am sure there is a cross over opportunity to apply this concept to low pressure injection molding. Ten years ago in the corrugated pipe industry throughputs of 4,000 lb’s per hour were off the map, today you routinely hear people talking about them.  Is it possible to continuously form a profiled solid or foamed extrusion at such speeds? I believe so.

For more discussion you can get in touch with me at Profile Pipe Machinery or please make a comment to this article.

TK

Certain statements in the article relating to a comparative assessment of forming velocity, wall distribution and long-term wear and tear with respect to the Corma and Fraenkishe machines were made without any objective basis or justification.  My intent of the article was not to take away from the long record of performance of the Corma corrugator design, but more to engage any readers who might be interested in corrugator comparisons to look at these specific aspects of corrugator operation.

We would encourage anybody interested in mold speed, wall distribution and long term wear to contact the respective corrugator manufacturer for more information and technical data.  To find further information out about these topics contact Corma at www.corma.com or Unicor at www.unicor.com.

Tony Kime