What a shell and tube heat exchanger does in your system
One fluid runs inside a bundle of parallel tubes, the second fluid circulates through the surrounding shell, and heat crosses the tube wall. Because the two sides are separated by a metal tube sheet rather than by plates and gaskets, the design tolerates high pressure, high temperature and dirty fluids, and the bundle can be built in alloys that a plate unit cannot use. That is why chillers, chemical plants, refineries, food lines and marine systems still specify it.
The price of that robustness is that the design has to be decided early. Pass arrangement, baffle spacing, tube velocity and the choice between a fixed, U-tube or removable bundle determine the pressure drop, the fouling behaviour and whether the unit can be cleaned at all. A quotation that only states an area has not answered any of those questions.
What we can change for you
Shell and bundle — diameter, length, tube count, pitch, baffle spacing
Materials — shell, tube, tube sheet and channel in the alloy your fluid needs
Connections — nozzle size, position, orientation and flange standard
Mounting — support feet, saddles and lifting points to your installation
Four things that decide whether the unit works
These are the four questions that come up in almost every buyer's first email — and the four places where a cheap quotation usually fails.
1. The area is quoted, the hydraulics are not
A unit sized only by square metres may meet the duty on paper and still be unusable: tube velocity too low and it fouls, too high and it erodes; pressure drop outside the pump curve and the whole loop has to be redesigned.
Our answer: U value, tube velocity, pressure drop on both sides and fouling allowance are calculated and issued with the quotation, so the numbers you approve are the numbers we build to.
2. One tube joint between product and service fluid
A tube-to-tube-sheet joint is a few millimetres of expanded or welded metal. In pharma, food or any duty where a leak means contamination rather than a repair, that single barrier is the risk the whole purchase has to be judged on.
Our answer: expanded, welded or expanded-and-welded joints to your specification, a double tube sheet where cross-contamination is not acceptable, and a pressure test record per serial number.
3. The alloy is chosen to hit a price, not a duty
Carbon steel on brine, seawater or an acidic stream fails inside the first year, usually at the tube sheet. Replacing one unit is cheap; the shutdown, the lost batch and the damaged reference account are not.
Our answer: shell, tube, tube sheet and channel are specified separately — SS304/316L, copper-nickel 90/10, titanium, duplex — against your fluid list and water analysis.
4. A design that cannot be cleaned
A fixed tube sheet cannot be opened on the shell side. If the fluid fouls, the unit loses capacity quietly over eighteen months and there is no way to brush it — a decision that was made at the drawing stage and discovered too late.
Our answer: we tell you what your duty allows before quoting — fixed, U-tube or removable bundle — including the cost and the maintenance consequence of each.
Where these units are installed
Six duties cover most of what leaves our workshop. If yours is close to one of them, the starting drawing already exists.
Chiller and heat pump OEMs
Evaporator, condenser and economizer bundles built into your frame, with nozzle positions agreed before the shell is cut.
Chemical and pharmaceutical
316L, duplex or titanium wetted parts, and a double tube sheet wherever product and service fluid must never meet.
Marine and offshore
Copper-nickel 90/10 and titanium bundles for seawater duty, with material certificates issued against the vessel or project number.
District cooling and HVAC
Large water-to-water units with removable heads, so the site maintenance team can brush the tubes without lifting the shell.
Food and beverage
Hygienic pass arrangement, full drainability and wetted surfaces a CIP cycle can actually reach.
Power, ORC and waste heat recovery
High temperature and high pressure designs with expansion compensation, rated for the loop rather than for a catalogue.
Choosing between the four designs
One decision fixes most of the cost and all of the maintenance. It is made at the drawing stage, not after the first shutdown.
| Design | Use it when |
|---|---|
| Fixed tube sheet | Both fluids are clean and the budget is tight. Cheapest and most compact, but the shell side cannot be opened for mechanical cleaning. |
| U-tube | The shell side fouls, or the temperature difference is large. One tube sheet, free thermal expansion, bundle can be pulled out. |
| Floating head | Both sides must be opened for cleaning, and the unit sees wide temperature swings. Costs more and needs a larger shell diameter. |
| Double tube sheet | Product and service fluid must never mix. Two independent sheets with a vented gap, so a leaking joint shows up as a drip, not as contamination. |
Not sure which one? Send the duty and the fluid list. We will tell you which of the four works for it — and, more usefully, which one will not.
From your data to a tested unit
Four steps, and you approve the drawing before a single tube is cut.
Duty and fluids
Flow, inlet and outlet temperatures, allowable pressure drop and the fluid list. A data sheet is ideal; a spreadsheet is enough.
Thermal design and drawing
U value, tube velocity, pressure drop and fouling allowance calculated, then a GA drawing with nozzle positions for your approval.
Fabrication and test
Bundle, shell, tube sheet and heads built to the approved drawing, then hydrostatic test and, where required, a helium leak test per serial number.
Documents and packing
Material certificates, test records, GA drawing, IOM manual and a packing list your customs broker can work from.
What to send for a technical answer
Fluid names and concentrations · flow rates · inlet and outlet temperatures · allowable pressure drop · design pressure and temperature · connection standard and orientation · GA drawing if the unit must fit an existing space.
Send the data sheetWhich overseas buyers request a quotation
Six buyer types raise most of our RFQs. Each one opens with a different question — these are the ones we answer first.
Chiller and heat pump OEMs
Can the bundle fit our existing frame, and can you match our nozzle drawing?
Asks for: frame dimensions, connection schedule, sample unit before series order.
Chemical and pharma engineering firms
Will you supply a double tube sheet, and can the shell side be opened for inspection?
Asks for: wetted material list, surface finish, certificate package, test records.
Marine and offshore yards
CuNi or titanium on seawater — and will the certificates clear class survey?
Asks for: alloy grade, sea water velocity, lifting points, sea freight packing.
District cooling and HVAC contractors
Removable heads, lifting points, and a footprint that fits the plant room.
Asks for: site dimensions, lifting weight, pump head available, delivery window.
Food and beverage processors
Does it drain completely, and can CIP reach every wetted surface?
Asks for: pass arrangement, drain position, gasket material, cleaning procedure.
Replacement and retrofit buyers
Can you reverse-engineer a bundle from the old nameplate and a photo?
Asks for: nameplate photo, nozzle centre distances, tube count, pass arrangement.
Questions buyers ask before the RFQ
Which design should I choose — fixed, U-tube, floating head or double tube sheet?
It follows from how the unit fouls and from whether the two fluids may ever mix. Clean fluids on a tight budget point to fixed tube sheet, a fouling shell side or a wide temperature swing to U-tube or floating head, and any contamination risk to double tube sheet.
What do you need from me to quote?
Flow rates, inlet and outlet temperatures, fluid names and concentrations, allowable pressure drop, design pressure and temperature, and the connection standard. A GA drawing is only needed when the unit has to fit an existing space.
Can you build a replacement bundle for a unit we already run?
Yes, where the shell is still sound. We work from the nameplate, the original drawing or measured nozzle positions, and match tube count, pitch and pass arrangement so the new bundle drops in.
What testing and documents come with the unit?
Hydrostatic test on both sides, plus a helium or pneumatic leak test where the duty calls for it. Records are issued per serial number: material certificates, test reports, GA drawing, IOM manual and packing list.
Do you build to TEMA, ASME or PED?
Drawings are issued to TEMA practice and can be adapted to your own company standard. Where a stamped or notified-body route is required, say so at RFQ stage and we confirm what we can supply before quoting.
What is the lead time?
It is set by alloy availability, tube supply and test scope, so we give the date at drawing approval rather than at quotation. Once the drawing is accepted, that date goes into the order.
Hangzhou Airman Environmental Technology Co., Ltd. is one of the most professional shell and tube heat exchanger manufacturers and suppliers in China, specialized in providing high quality products. We warmly welcome you to buy customized shell and tube heat exchanger made in China here from our factory.
evaporating heat exchanger, heat exchanger methacrylate, heat exchanger lithium