Frequently Asked Questions (FAQ)
How much does a twist tube cost per foot?
How can I get a copy of the engineering data?
Why can't I get a price without all of the design and development work?
What is the development process of becoming a Delta t customer?
How long does it take to get samples?
What is the lead-time for production orders?
What are the advantages of the DELTATWIST™ tube?
Does Delta t do any fabrication other than tube twisting?
What is the range of sizes that Delta t can twist?
What part design assistance can Delta t offer?
What materials can be twisted?
What industries use twisted tubes?
How much does a twist tube cost per foot?
The cost of a DELTATWIST™ tube depends upon many factors. The cost of the material is dependent upon the metal grade selected, tube OD, tube wall thickness, standard or special sizes, welded or seamless tube and order size. The fabrication costs are dependent upon order size (set up costs), other fabrication processes required and tolerances required. Given all of these variables, the best way to price a DELTATWIST™ tube is one application at a time. We are happy to provide quotes.
How can I get a copy of the engineering data?
The parameters of a twist configuration (flute OD, flute ID, number of starts and flute pitch) are all individually and continuously changeable, resulting in thousands of different twist configurations for a given raw tube. We do not have standard twist configurations. Each of these different twist configurations will have it's own heat transfer improvement and pressure drop characteristics.
With so many configurations, we have never developed a 'set' of standard twist tubes for which to publish engineering data. The engineering and design are done one application at a time to meet the specific requirements of the customer. We would rather fit a DELTATWIST™ tube to the customer's application than require a customer to fit his application to one of a set of standard twist configurations.
Why can't I get a price without all of the design and development work?
We don't know what something will cost until we know what that something is. The part has to be designed, assuring that it will meet the customer's requirements, and then priced. We are glad to do this design work.
What is the development process of becoming a
Delta t customer?
Inquiry Phase - Conversations between the customer and Delta t determine if the application is one where the Delta t product will be helpful. The customer will furnish the information and requirements for their application by completing an "Engineering and Quote Request" form.
Design Phase - Delta t designs a unit to meet the requirements of the customer. They will then provide a quote describing this design with costs in prototype and production quantities. The first design approval comes from the Customer.
Sample Phase - If the design and costs are satisfactory with the customer, Delta t will fabricate sample(s) as ordered by the customer.
Test Phase - The customer will test the Delta t unit in one of their pieces of equipment. The testing is done in this 'real-life' condition rather than in a Delta t lab, for there are parameters in an actual unit that will not be duplicated in the lab. If the unit does not meet all of the requirements, Delta t can, with the test results, 'calibrate' their computer models to produce a design that will work. Any second generation samples are at no cost.
How long does it take to get samples?
Sample delivery can be from 1 week to several weeks, depending upon such factors as the material needed, whether we have any of that material in stock, when machine time will be available, when tool building labor (if needed) will be available, etc.
Prototypes are 'hand built' without the aid of machines or tooling. Also all set up time is allocated to just one, or a few, parts. The prototype parts are more expensive than the production parts. They are a necessary component of the part development process.
What is the lead-time for production orders?
Total lead-time is a combination of material lead-time, tooling lead-time, fabrication lead-time plus freight time. Material lead-time can vary from 2 days to 12 weeks depending upon the grade of material purchased the amount of material purchased and if the material is a standard size. Tooling lead-time will be concurrent with the material lead-time. This tooling lead-time may be more or less than the material lead-time depending upon the quantity and complexity of the needed tooling. The fabrication lead-time can be from 2 days to 4 weeks depending upon the fabrication processes needed to make the part. Shipping the parts to the customer can vary from 1 to 5 days, domestically, and up to 10 days, overseas, all depending upon the location of the customer and the method of transportation selected.
For instances of blanket orders with consistent shipment quantities and frequencies, the lead-time can be reduced to the fabrication time and freight out time only.
What are the advantages of the DELTATWIST™ tube?
More surface per foot of tube - up to 50% more.
Heat transfer is dependent upon the surface area it has to transfer through. More surface per linear foot of tube will give that percentage of increased heat transfer.
More turbulence - The turbulence producing design will break up the 'boundary layer' of fluid on the surface of the tube (which tends to insulate), will mix the fluids producing a more uniform temperature across the fluid and will keep the fluid in the 'turbulent range' at much lower Reynolds numbers.
More flexibility - This flexibility will allow the tube to be coiled or bent at a tighter radius resulting in a smaller package size. The tube can also be used in applications of vibration and misalignment.
Does Delta t do any fabrication other than tube twisting?
For some customers, we twist a tube and put it in a box.
For other customers we anodize, assemble, bend, blast, bracket, braze, coil, coat, deburr, dry, electropolish, end form (enlarge, reduce and shape change), glue, heat treat, inspect, leak test, paint, polish, passivate, pressure test, test, UL/CSA list, weld and most any other process needed to make a part, all at tolerances you need.
Many (most) of the processes at Delta t are made at our facilities by our personnel. We have the ability to make processes (machines and tooling) that make parts with less labor or less skilled labor, thus reducing the cost of the part.
The processes at Delta t are created to meet a customer's needs. We do not build a process and then go try and sell them.
What is the range of sizes that Delta t can twist?
The maximum size is dependent upon the length and horsepower of our twist machines. The horsepower required is a combination of tensile, tube OD and tube wall thickness. The following sizes are the current approximate maximum tube sizes we can twist.
Aluminum 2.75" OD x .049" wall
Copper 2.25" OD x .028" wall
CuNi 2.0" OD x .028" wall
Carbon Steel 2.0" OD x .028" wall
Stainless Steel 1.5" OD x .035" wall
Welding multiple pieces together can make an unlimited length of tube, continually twisted.
If an application has the volume to justify building a machine to do larger tubes, we will build it. We have the capability to make samples of larger DELTATWIST tubes on a machine that is not suitable for production.
What part design assistance can Delta t offer?
HEAT EXCHANGE ENGINEERING - Delta t will take the specifications that are provided by the customer that describes his application, and design a part (tube, coil, etc…). We will then provide the customer with a description/drawing of the part and a quote of that part in both prototype and production quantities. There may be variations in design and/or quantity for the customer to choose from. The material selection and design approval are with the customer.
MANUFACTURING ENGINEERING - During both the development and production phases of a part, the manufacturing engineers at Delta t will work to conceive and recommend process and part changes that will be of benefit to the customer. These changes may be part design changes, process changes that remove operation (eliminating labor) or process changes that automate operations (exchanging labor dollars with fewer equipment dollars).
What materials can be twisted?
Any material can be twisted, give the correct temper (aluminum, carbon steel, stainless steel, titanium, copper, CuNi).
What industries use twisted tubes?
As heat exchangers and flexible tubing are used in every industry, so can the DELTATWIST tube be used in every industry.
How we do this is part of the secret. Anything is easy if you know how and have the correct tools. Delta t knows how and has the right tools. More important than 'how a tube is twisted' is 'how a twisted tube will benefit your heat transfer application.
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