Views: 0 Author: Site Editor Publish Time: 2026-09-21 Origin: Site
CSTHEATEXCHANGER builds fin tube heat exchanger samples directly from customer drawings before any volume order is placed. We have just completed production of one such build-to-drawing sample. This article explains how we take a fin-and-tube coil drawing through review, sample fabrication, leak testing and shipment, what a drawing needs to contain, and how the sample stage protects you from costly mistakes in series production.
At CSTHEATEXCHANGER we manufacture standard copper tube / aluminium fin commercial coils as well as heavy industrial finned tube heat exchangers for process applications, using water, steam, refrigerant, glycol, ammonia, CO2, thermal oil and other media. Building a first-article sample to the customer's drawing is a normal part of how we start a new project.
The sample completed in this project was built to the customer's approved drawing revision and delivered with the following documentation:
Dimensional inspection report against the drawing (overall dimensions, connection positions, fin pitch, tube count).
Leak / pressure test record at the test pressure stated on the drawing.
Material declaration for tube, fin, header and casing.
Photographs of the finished coil before packing.
A fin tube heat exchanger looks simple — tubes, fins, headers, a casing — but almost every dimension interacts with another. Fin pitch changes air-side pressure drop; tube circuiting changes refrigerant distribution; casing flange positions decide whether the coil actually fits the unit it is going into. A drawing can be correct on paper and still fail at installation.
The sample stage exists to catch that early. When CSTHEATEXCHANGER builds one physical coil to the approved drawing, the customer can:
Fit-check the coil in the real cabinet, duct or frame.
Performance-test it on their own rig against the specified duty.
Confirm materials and finish — fin coating, casing material, header type — before we commit tooling and material for the full batch.
Freeze the drawing revision that all subsequent production will follow.
Only after the customer approves the sample do we release series production. This is the same sequence we apply to our shell and tube units, and it is the reason a CSTHEATEXCHANGER production coil matches the sample the customer already tested.
Every drawing set that reaches our engineering team goes through the same checklist before a single tube is cut.
We confirm the tube outside diameter, wall thickness and material against what we run in production. Our standard tube programme covers:
Tube OD | Standard plain wall | On request |
|---|---|---|
5 mm | 0.28 mm plain | 0.21–0.40 mm rippled tube |
7 mm | 0.30 mm plain | 0.25–0.45 mm rippled tube |
9.52 mm | 0.35 mm plain | 0.40 / 0.50 / 0.70 mm plain; 0.30–0.50 mm rippled |
12.70 mm | 0.35 mm plain | 0.40 / 0.50 / 0.70 mm plain; 0.35–0.61 mm rippled |
15.87 mm | 0.40 mm plain | 0.50 / 0.70 / 1.0 mm plain |
If a drawing calls for a tube outside this range, we flag it and propose the nearest equivalent rather than silently substituting.
Fin material: 8006 H22 aluminium alloy as standard; copper foil or stainless steel fins on request.
Fin surface: flat, corrugated or louvred.
Fin coating: hydrophilic, hydrophobic or gold-epoxy coated foil; tin coating of the finished coil is also available.
Fin pitch and fin thickness are cross-checked against the air-side pressure-drop limit stated on the datasheet.
Number of rows, tubes per row and circuit arrangement.
Header material: steel manifolds are our default for dry coolers, water coils and steam coils; copper manifolds for other products. The drawing is checked for consistency with the fluid.
Connection sizes, positions and orientation (left-hand / right-hand, top / bottom feed).
Casing sheets are available in galvanized steel, stainless steel, plain steel, copper or aluminium. We check flange dimensions, mounting-hole pattern and drain-pan interface against the customer's cabinet drawing.
Even on a pure build-to-drawing job, we re-run the coil selection from the process data (air flow, entering/leaving air conditions, fluid, flow rate, inlet/outlet temperatures). If the drawing cannot meet the stated duty, we tell the customer before sampling — not after the coil is installed.
The output of this review is a short technical report and a marked-up drawing. Once the customer signs off, the sample is released to the shop.
The same drawing-to-sample process applies across our full fin-and-tube range:
Commercial HVAC coils
Hot water coils, chilled water coils, steam coils and steam distributing coils
Evaporator coils, condenser coils, A-frame evaporator coils, multiple-system evaporators
AHU coils, dry cooling coils, rear-door cooling coils for computer rooms
All-aluminium heat exchangers and air-to-water heat exchangers
Industrial coils and finned tube units
Elliptical (oval) finned tube heat exchangers — staggered tube arrangement for compactness, high heat-transfer coefficient and lower air-side pressure drop
Steam air heaters, flue gas air heaters and flue gas waste-heat recovery units
Boiler economizers and air cooler tube bundles
Stainless steel cooling coils and E-coating anti-corrosive cooling coils for aggressive environments
Tube fin air-cooled heat exchangers for hot-air heating, cooling, dehumidification and drying
Typical industries we build for include light industry, construction, machinery, textile, printing and dyeing, electronics, food, starch, pharmaceuticals, metallurgy and painting lines.
Yes. Building a first-article sample to the approved drawing is our standard starting point for new fin tube projects. Series production is released only after the customer approves the sample.
Yes. We review the drawing for manufacturability, materials and thermal performance, return a marked-up drawing for approval, and then build the sample to that revision.
We will select the coil, prepare the drawing and send it for your approval before sampling. Please provide air flow, entering and leaving air conditions, fluid type, flow rate, inlet/outlet temperatures and any dimensional limits.
Our standard programme covers 5 mm, 7 mm, 9.52 mm, 12.70 mm and 15.87 mm outside diameter, in plain or rippled tube, with the wall-thickness options listed in the table above.
8006 H22 aluminium alloy as standard; copper foil or stainless steel fins on request. Fin surfaces can be flat, corrugated or louvred. Hydrophilic, hydrophobic or gold-epoxy coated fin stock is available, and finished coils can be tin coated.
Yes. Matching face dimensions, connection positions, casing flanges and mounting holes is the normal scope of a build-to-drawing order. Where the original coil under-performed, we can propose internal changes while keeping the external interfaces unchanged.
Every sample is pressure/leak tested to the value stated on the approved drawing and shipped with the test record and a dimensional inspection report.
If you have a fin tube heat exchanger drawing — for a new unit, a replacement coil, or a prototype you need to validate before volume production — send it to CSTHEATEXCHANGER and we will return a technical review, a sample quotation and a lead time. If you only have performance data, we will prepare the drawing for you.
Email: info@cstheatexchanger.com
International business: +86 0519 8878 2189
Website: https://www.cstheatexchanger.com/
CSTHEATEXCHANGER — from your drawing to a tested fin tube heat exchanger sample, and from that sample to production you can trust.
