1) What is the advantage of buying Drilled Brass and Naval Brass plates from us?
Necessity is the mother of invention. European Plate rollers are able to give large plates which are 1200 mm x 2400 mm in size. This enables the user to cut their requirement from the larger plate with limited wastage. Our rolling size limitation is 700 mm x 1600 mm which does not offer us this option. We have therefore moved to the ready-to-use drilled tubesheets and circles and plates in the made-to-order market. We are able to recycle the scrap and thus reduce the cost. Since about 40% of a drilled tubesheet falls off as scrap, recycling makes the activity substantially more cost effective.
2) Why do you outsource?
Our regular clients rely on us. They often prefer to deal through us. So our outsourcing is a service we provide to our customers based on our long experience of purchasing engineering goods.
3) Do you take responsibility for your outsourced supply?
Yes. This is why our customers ask us to handle their third party business. We only get the work outsourced if we know the supplying facility well or have done our due diligence on it.
4) Are you willing to outsource anything the customer requires?
Only if we have confidence in the product and people involved.
1) Will a Turbulator help in all cases?
No. For maximum efficacy, the following conditions need to be present.
- The fluid is viscous.
- The shell or airside coefficient is much higher or can be made higher than the tube side coefficient. Otherwise there is little sense in increasing the coefficient on the tube side.
- The flow is not already turbulent.
- Generally liquids with viscosity like water do not benefit from turbulators and liquids like oils do.
- Gasses and air on the tube side have a significant improvement with turbulators.
2) Can you guide us as to whether a Turbulator is warranted in our application?
Yes, of course.
We thrive on client engagement.
However there are two possible situations.
In the easy first case, we have the data and can guide you.
In the second case, we have an experience of clients already doing it but do not have the data. In a lot of such cases we have worked with clients to get their prototypes developed and know of their success as evidenced by orders but do not have hard data to support it.
Examples of the second case are:
Our clients’ use of turbulators in static mixing and in-line reacting. Our clients’ use of turbulators in Falling Film Evaporators.
3) Do you have a static knowledge database or do you continuously research, experiment and add to it?
Thermodynamics Research Division:
Systemic complacency is a horrible thing. The Thermodynamics Research Division was thought up to counter just that.
We’re an engineering company that makes precision products for heat transfer applications the world over. It’s not enough for us to stick to what we know. Making Fin Tubes or Turbulators a certain size, with a certain diameter, from a certain material, with x loops and y turns and hiding behind the “what’s worked before”.
The Thermodynamics Division exists in two forms. One is an idea that challenges everybody who works here daily to think up new applications, ask questions of our existing products and constantly make them walk a validation tightrope to ensure that they’re well capable of making it to the other side. The other form of TRD is a Test Rig located in Pune that’ll empirically simulate conditions where all those questions, new applications and performance ratings can be answered, tested and validated.
The Test Rig has been set up in collaboration with Bormash LLC (Russia) and houses a mini heat exchanger, a high powered boiler, a wind tunnel, sensors to pick up flow rates, pressure differentials, temperatures at both inlets and outlets and a SCADA system that’ll translate all the simulation data to an on-site computer, generating graphs and performing calculations to give a well-rounded picture of what sort of performance our products are capable of.
It’ll be a validation headquarters for our existing products.
And a proving ground for our prototypes.
Understandably, the data generated from these test runs is strictly confidential and will only be shared with members of the conceptengg.com network. The data may be provided on request at the discretion of top management but only after a prescribed NDA form is signed and sent to CEI’s corporate headquarters.
4) Which is the best type of Turbulator?
It is a good question and our answer would be dependent on your application. The following are the important questions to ask.
- What the viscosity of the fluid is.
- What the flow rate is. Higher the flow rate, higher the pressure drop for every type of turbulator. This increase is always more than proportional. So if the flow rate and viscosity are high you may need a lighter turbulator.
- Is the fluid dirty and does the tube have to be periodically cleaned. In this case though the Rigid Soldered Turbulator may give a higher performance, it cannot be removed. Here, a flexible or twisted tape may be warranted.
We will be happy to help you select the right turbulators for your application. In very general terms:
- The rigid Turbulator has the highest performance. But cannot be removed for cleaning. It is also more expensive than other turbulator types.
- This is followed by the flexible Turbulator. Which is cheap, easy to install and both removable and cleanable.
- This is followed by the twisted tape. This is especially useful when retrofitting an existing heat exchanger where there are limitations on the allowable pressure drop and number of passes. They are also ideal under various conditions of flow, allowable pressure drop ranges and viscosity. Being an old warhorse, its data is part of the HTRI package used by many heat exchanger manufacturers.
5) What if I am worried about fouling?
Generally, turbulators arrest the build-up of scale on the tube wall due to the turbulation they create. This protection from scale build-up is very substantial. However, over time scale can build up for dirty liquids. The beauty of turbulators is that due to the increased efficiency provided by them, the exchanger will continue to perform even after some scale build-up. So when the exchanger stops performing the scale buildup may have become substantial. If it is so much that it binds the Turbulator to the tube wall it will become difficult to clean or remove the Turbulator. In such a case the soldered Turbulator is not warranted. These should be used for cleaner liquids. The Flexible Turbulator has been given a strong stainless steel spine. This allows it to be pulled out for cleaning of the tube. However, if very substantial scale has been allowed to build up the loops may become damaged and the Turbulator may not be reused. If the tube is substantially blocked then removing this type of Turbulator may become difficult. The twisted tape Turbulator is easiest to remove clean and reinsert.
6) Can I reuse the turbulators?
The rigid Turbulator cannot be removed and reused.
The flexible turbulators can be removed and reused after cleaning. This of course depends on the level of fouling that has occurred.
The twisted tape Turbulator can be removed, cleaned and reused a number of times.
7) Can you ship in small lots for my prototype?
Yes we can. We are very interested in helping our customers develop their concepts and products and you will find us very cooperative.
8) What if I need a small quantity for a small specialized heat exchanger?
Again, we thrive on relationships and a huge community of happy customers. We are happy to help and courier small quantities to your door as required by you.
9) How do you deliver?
We do sea, air and courier shipments.
As a lot of our customer requirements are urgent or small in weight or for a specific exchanger, we have developed very good rates with the courier company and do door delivery of thousands of kilos per year through courier. In fact our courier rates have been designed so that delivered to your door it is cheaper than airfreight.
Again this is to build a meaningful relationship with you the customer.
10) How do I secure the turbulators in place?
This depends on your Turbulator type.
Rigid turbulators are generally soldered inside the tubes or at least brazed at the ends. They are thus bonded to the tube and do not require further securing. Here the best option is to buy tubes with the turbulators pre-fitted.
Flexible Turbulators are pressure fit and in most cases do not need to be secured. As a measure of abundant caution they can be provided with anchors at the ends. Download our catalogue for details. You may also see the section on Flexible Turbulators on our website.
Twisted Tape Turbulators come with a hole at the ends. They can be secured by passing a wire through these holes in the manner illustrated in the section on Twisted Tape Turbulators. They too, can be secured at both ends if needed.
11) Can you help me design? Is there a cost to it?
We will be happy to help you design. Depending on the project we charge USD 100, 150 or 200 per exchanger (to cover our cost). For regular customers who work in partnership with us we may waive this fee.
12) Can you make a Turbulator as per my requirement and specification?
We will be happy to do this as long as it is within the realm of our abilities. Most turbulators are.
13) Can I have access to your data?
Our data has been prepared for our customers and is meant to be of use to them. However, quite naturally we wish to protect it from our competitors and uncommitted one-time customers.
We wish to build a relationship with you as your turbulator expert and will gradually make available all the data you require as we build a good working relationship.
14) Can you supply tubes already fitted with soldered or other turbulators?
Yes, we can. In fact, we would be happy to and have arrangements with good tube mills for tube supply as we buy large quantities for our fin tubes division.
15) What type of Turbulator do I use if my fluid is dirty?
Please see our answer to question 5.
1) Can you assist with the design for my application?
Absolutely, we can.
2) Do you charge for design?
We are a pretty proactive bunch. So, while we do charge a small fee per design to cover our costs, we absorb these costs when it is for a regular customer or where we are working jointly on a project. We also refund the fees in case it is followed by an order.
3) Why do Pin fin tubes weigh less than L type fin tubes?
Pin Fin tubes are made from wire. Being cylindrical, wire has a larger area per unit of weight than the strip used in L type fin tubes. Also, due to the looped nature of the wire, less material is put on the tube than in the case of L fins. Consequently, the surface area of fins per meter of tubes is also less. However due to the superior turbulence created by the looped wire the actual heat transfer per meter of tube is significantly higher than in the case of L Type Fin Tubes. All of this together contributes to the weight differential between wire wound fin tubes and L Type Fin Tubes. In the case of similar metals, it is weighing half and in the case of Aluminium L fin vs. Steel wire fin they weigh about the same.
The higher performance S5 pin fin tubes have an airside heat transfer performance per meter of tube that is 250% of the L type fin tubes.
4) How do we compare the surface area for Pin Fin Tubes and L Type Fin Tubes?
Actually we don't compare the surface area of the two types of fin tubes. The reason is that it is not comparable as the wire fins are way more efficient. However it makes sense to compare the linear heat transfer coefficient per foot or meter of tube to get a relevant comparison.
5) Why is airside pressure drop important?
Pressure drop is important as it is a root cause of power consumption. The power consumption increases exponentially (refer to the fan laws) with a linear increase in pressure drop. This is why it is important to design equipment with optimum number of rows giving the best trade-off between power consumption and heat transfer. With Pin Fin tubes, as the number of rows is halved, the power consumption is significantly reduced.
6) Why can you not give Wire Wound Fin Tubes with Aluminium fins?
Aluminium does not lend itself to soldering. Hence we cannot use Aluminum tubes as Pin fin tubes are soldered.
7) What causes the temperature limitation on the Pin Fin Tubes?
Pin fin tubes have the pin fins soldered to the tube for good bonding and strength. The consequence is that if the melting point of solder is reached, the solder softens and the pin fins come loose. However, the solder we use has a melting point of 190 degrees C and on request a high melting point solder is provided with a melting point of 290 degrees C.
8) How do turbulators help?
The Pin fin tube has a tremendous airside heat transfer coefficient. When the fluid on the tube side is viscous the tube side heat transfer is limited reducing the overall heat transfer coefficient. By using turbulators on the tube side it is possible to significantly increase the tube side heat transfer rate also. So by using turbulators we are able to match the heat transfer coefficient on both sides to increase the overall heat transfer coefficient and hence performance.
9) Why is the advantage in steam heaters so pronounced?
Steam has a very high tube side coefficient. The tube side is therefore the dominant side. This situation begs for the airside coefficient to be high to best utilize the heat transfer potential of steam. With Pin Fin tubes we are able to achieve a very high airside and therefore overall heat transfer coefficient.
10) What is the best way to clean a Pin Fin tube?
Unlike L Type Fin Tubes, the pin fins are soldered to the tube and have a very strong bond. It is possible to hose the tube off for cleaning. The L Fin could get damaged by high pressure hoses, but not the Pin Fin.
11) How do we cut the Pin Fin tube into smaller lengths?
After cutting the tube, the wire loops (soldered to the tube and held in place by a binding wire) have to be pulled out with the binding wire with a set of pliers. After removing the required number of fin rows, the fins must be removed from the binding wire. The wire can then be tied back around the tube. This procedure may sound complicated but is easy to do. The solder residue must then be cleaned from the tube. This can be done by heating and wiping off.
12) Can we order the tubes in smaller lengths to prevent having to cut them at site?
Yes we can give the tubes in the required lengths.
13) What is the market acceptance of Pin fin tubes?
The Pin fin tube has been around for several decades in the UK and Australia where Copper Pin fins are popular. We have been able to produce it with Carbon Steel fin and Stainless Steel fins to develop its potential for steam applications. It is currently not used by Oil refineries, however, it is extensively used in Power Plants as well as in Machinery of all sorts.