Neometrix / Aviation & Aerospace Fuel Test Systems / Heated & Cold Fuel Supply Rig / NMX-HCF-30

NMX-HCF-30 · ENGINEERED-TO-ORDER CLASS — COLD SOAK · HOT FUEL · HELD STEADY

Heated & Cold Fuel Supply Rig. Fuel is not one liquid. It is a different liquid at every temperature.

Name: Heated & Cold Fuel Supply Rig
SKU: NMX-HCF-30

A fuel-system test run on room-temperature fuel tells you about room-temperature fuel. In service, the same hardware meets fuel that is thick and waxy at one end and hot enough to oxidise at the other.

So the rig has to make the fuel arrive at the temperature the test asks for, at the flow and pressure it asks for, and hold it there. In this rig, the temperature is part of the supply.

Discuss a fuel supply rig Capability note (PDF)

A heated and cold fuel supply rig on one stainless steel skid: two tall upright insulated vessels, a plate heat exchanger and a pump joined by insulated pipework, and a plain stainless steel control cabinet beside the skid, and no people

Fig · 01 — A heated and cold fuel supply rig: insulated conditioning vessels, a heat-exchanger and pump skid, and a control cabinet — illustrative render.

The cold end

chilled fuelcold soak, wax and water managed

The hot end

heated fueloxygen managed, deposits avoided

The delivery

held steadyflow, pressure and temperature together

The safety basis

flameproofhot fuel treated as a hazardous area

Status

engineered to orderno unit yet delivered

ISO 9001ISO 14001ASTM D1655 aviation fuel referenceASME Section VIII vessel referenceIEC 60079 hazardous-area reference

Overview

Why the fuel's temperature matters more than the pump that moves it.

Because a fuel-system test on the wrong fuel condition proves the wrong thing, however accurate the pump and the meter.

Fig · 02 — The rig in one picture: the fuel is conditioned first, delivered to the unit under test second, and returned last, with the thermal utility and the nitrogen blanket behind the conditioning stage.

A pump test on comfortable fuel says little about the day the fuel is cold or hot.

What the rig is actually for

It supplies fuel to a unit under test — a pump, a valve, an injector, a heat exchanger or a whole fuel sub-system — at a chosen temperature, flow and pressure, from a cold-soaked condition to a hot one. It holds each condition steady while the test runs.

Why fuel at the wrong temperature proves little

Fuel is a mixture, and its properties move with temperature. Cold, it thickens and can throw wax crystals that block strainers. Warm, it thins and its vapour pressure rises. Hot, it starts to oxidise. A component that behaves at room temperature can still stick, starve or foul at either end.

Why cold is a problem of patience

A cold soak takes time: the whole tank, the loop and the unit under test have to reach the temperature together. Wax that has formed does not clear the moment the fuel warms, and traces of dissolved water can turn to ice and block a filter. The rig chills the fuel evenly and waits, rather than chilling the outlet and hoping.

Why hot is a problem of chemistry

Hot fuel that carries dissolved oxygen oxidises, and the products can deposit on hot surfaces as a coating that fouls heat exchangers and changes the flow. So the rig keeps its own heated surfaces only slightly hotter than the fuel, and blankets the fuel with nitrogen, so that it does not change the fuel it is meant to deliver.

Why the flow is measured by mass

An engine burns fuel by mass, and the density of fuel moves with temperature. A meter that counts volume drifts as the fuel warms or cools. The rig measures mass flow directly, and logs temperature and pressure beside it.

Why the whole rig is designed as a flameproof installation

Hot fuel can give off flammable vapour, and the space above it has to be kept inert. That makes the rig a classified hazardous area from the start: the electrics, the venting, the interlocks and the nitrogen blanket are designed together, not fitted afterwards.

The cycle

Fill, condition, soak, deliver, return, and make safe.

Six steps, and the two that make the test valid are the conditioning and the soak, in that order and before any flow reaches the unit under test.

FIG · 02HEATED & COLD FUEL SUPPLY RIG · FILL / CONDITION / SOAK / DELIVER / RETURN / MAKE SAFE — CONDITION THE FUEL, THEN TEST

The step people skip is the soak. Fuel that has reached temperature at the outlet has not necessarily reached it in the tank, the loop or the unit under test.

Fig · 03 — The same strainer and pipe wall at three fuel conditions: wax collecting on the strainer when the fuel is cold, clear flow in the comfortable middle, and a deposit layer building on a heated wall when the fuel is hot — a drawing of the idea, with no values.

1 · Fill

The conditioning vessel is filled and purged with nitrogen, so the fuel starts with as little oxygen and water as possible.

2 · Condition

The heating or chilling system brings the fuel toward the setpoint through the heat exchangers, without overheating the fuel at the heater surface.

3 · Soak

The fuel circulates until the whole tank and loop agree on the temperature, and the control system confirms it rather than assuming it.

4 · Deliver

Fuel flows to the unit under test at the requested pressure and flow, measured by mass, with temperature logged beside it.

5 · Return

Fuel comes back to the vessel, and samples can be taken so the condition of the fuel is checked during the test, not only before it.

6 · Make safe

The rig is brought to a safe temperature, drained or blanketed with nitrogen, and left in a defined safe state.

Work content

What the rig contains, element by element.

Read it as a checklist: a rig missing a row will buy that row back later, usually the first time a test result cannot be explained.

The heat-exchanger and pump skid of a fuel conditioning rig: a plate heat exchanger with clamped plates, a centrifugal pump with a plain motor and insulated pipework on a stainless steel frame, and no people

Fig · 04 — The heat-exchanger and pump skid at the heart of the rig: insulated pipework and a plate heat exchanger on a stainless steel frame — illustrative render.

Element	What it does	What matters
Conditioning vessels	hold and condition the fuel	insulated and jacketed, to a pressure-vessel code
Heating system	brings the fuel up to temperature	heated surfaces kept only slightly hotter than the fuel
Chilling system	brings the fuel down to temperature	even and patient, with no local freezing
Heat exchangers	transfer heat between the fuel and the utility	sized for the whole range and kept clean
Fuel pumps	move the fuel round the loop	suited to thick cold fuel and thin hot fuel
Nitrogen blanket & purge	keeps oxygen and moisture out of the fuel	hot fuel does not oxidise and the vapour space stays inert
Filtration	protects the rig and the unit under test	sized for cold, waxy fuel as well as clean fuel
Pressure control	holds the delivery pressure	steady across the flow range
Flow control & mass-flow measurement	deliver and measure fuel by mass	independent of the density change with temperature
Temperature measurement	reads the fuel at tank, loop and outlet	the soak is confirmed, not assumed
Return & sampling line	returns fuel and takes samples	fuel condition can be checked during the test
Insulation & heat tracing	keep the loop at temperature	no cold spots to trap wax and no hot spots to foul
Flameproof electrics, venting & interlocks	protect against flammable vapour	designed to the classified hazardous area
Control system & HMI	sequences conditioning, soak, delivery and safe state	the test cannot start before the soak is complete
Instrumentation, testing & documentation	prove the rig before handover	temperature, flow and pressure checks, with records

The row that decides whether a test result means anything is never a machine. It is the control system. The best heat exchangers and the best meter on a rig that lets the flow start before the soak is complete will deliver fuel at a temperature nobody asked for.

Fig · 05 — One rig, three support systems: the thermal utility for heating and chilling, the nitrogen blanket and purge, and the measurement of mass flow, temperature and pressure.

Full specification — expand

System	Insulated, jacketed conditioning vessels to a pressure-vessel code; a heating system and a chilling system with heat exchangers; fuel pumps for thick cold fuel and thin hot fuel; a nitrogen blanket and purge system; filtration; pressure and flow control with mass-flow measurement; temperature measurement at tank, loop and outlet; a return and sampling line; insulation and heat tracing; flameproof electrics, venting and safety interlocks; a PLC control system with instrumentation; and testing and documentation before handover
The One Idea	Fuel is not one liquid. It is a different liquid at every temperature, so the temperature is part of the supply, and the test should not start until the whole tank and loop have reached it
Why Cold	Cold fuel thickens and can throw wax crystals that plug strainers, and dissolved water can turn to ice in a filter, so the rig chills the whole loop evenly and soaks it, rather than chilling the outlet and hoping
Why Hot	Hot fuel that carries dissolved oxygen oxidises and can leave deposits on hot surfaces that foul heat exchangers, so the rig keeps its heated surfaces only slightly hotter than the fuel and blankets the fuel with nitrogen
Why Mass Flow	An engine burns fuel by mass and fuel density moves with temperature, so a meter that counts volume drifts as the fuel warms or cools, and the rig measures mass flow directly
Why Flameproof	Hot fuel can give off flammable vapour, so the electrics, venting, interlocks and nitrogen blanketing are designed together as a hazardous-area installation from the start
Standards	ASTM D1655 for aviation turbine fuel, ASTM D3241 for the thermal oxidation stability of jet fuel, ASME Section VIII for pressure vessels, and the IEC 60079 series for equipment in hazardous areas are the public references this class is designed against. Acceptance of the finished rig rests with the customer and their inspection authority
Configurations	A single-loop conditioning skid, a dual-leg rig with a hot leg and a cold leg, and a cell-integrated installation fed from bulk fuel with return, sampling and a data link
Scope Boundary	This is the temperature-conditioned fuel source for a unit under test. It is not an ambient-temperature fuel delivery skid (see aerospace fuel supply system) and not a bench built to validate one particular set of engine components (see integrated test rig for pumps and fuel coolers)
Status	Neometrix engineers heated and cold fuel supply rigs to order, and no delivered heated and cold fuel supply rig is claimed.

Configurations

One conditioning discipline, three ways to build the rig.

The soak, the safety basis and the order of operations are shared. What changes is how many legs there are and how they connect to the test.

Single-loop skid

One temperature at a time

A conditioning vessel, heat exchangers, pumps and mass-flow delivery on one skid, for bench-scale and component tests.

Dual-leg rig

A hot leg and a cold leg

Two conditioned legs that can be sequenced or blended, for tests that move between the cold end and the hot end.

Cell-integrated installation

Fed from bulk fuel

Bulk fuel feed, conditioning, return and sampling, and a data link to the test cell's own controls.

Fig · 06 — Three ways to build the rig, one conditioning discipline: a single-loop skid, a dual-leg rig with a hot leg and a cold leg, or a cell-integrated installation.

And the part that is not a machine at all, yet decides all three: the soak procedure — the defined step that keeps flow away from the unit under test until the whole tank and loop have reached the temperature.

Where it is used

Wherever the fuel's condition is part of the question.

The common thread is a fuel-system unit whose behaviour depends on the temperature of the fuel it is given.

Component qualification

Where pumps, valves, filters and injectors have to be shown to work with fuel at the cold and hot ends of their range.

Fuel-cooled heat exchangers

Where fuel is the coolant, and the exchanger has to be tested on fuel at the temperatures it will really see.

Engine & system test cells

Where the fuel feed to an engine or a sub-system has to match the condition of the fuel in the aircraft.

Fuel-system research

Where cold-flow, deposit and thermal-stability behaviour is itself the subject of the study.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 Why does fuel temperature matter so much to a fuel-system test?

Because fuel is not a single, fixed liquid. It is a blend of hydrocarbons, and its viscosity, density, vapour pressure and chemical behaviour all move with temperature. At the cold end, viscosity rises and the heavier components can start to form wax crystals; the aviation turbine fuel specification sets a freezing-point limit precisely so that fuel stays fluid in the cold. Wax, and traces of dissolved water that turn to ice, can block strainers and filters. At the hot end, the fuel is thinner, its vapour pressure is higher, and in the presence of dissolved oxygen it starts to oxidise. Aircraft fuel systems meet both ends: fuel can sit cold-soaked for hours, and fuel is also used as a coolant, so it reaches the components downstream hot. A test run on fuel at room temperature covers only the comfortable middle of that range, and a component can pass there and still stick, starve or foul at either end. That is why the temperature has to be a controlled part of the fuel supply, not an accident of the workshop.

Q · 02 Why is chilling fuel harder than it sounds?

Because the difficulty is the whole volume, not the outlet. Chilling a small stream at the outlet is easy; getting every part of the tank, the pipework and the unit under test to the same cold temperature takes time and even heat removal. If part of the loop is colder than the rest, wax can form there and plug a strainer even though the average temperature looks fine. Wax is also slow to clear: the freezing point of a fuel is defined as the temperature at which the last wax crystal melts on warming, so fuel that has been chilled below it has to be warmed above it, and given time, before it is a uniform liquid again. Dissolved water adds a second problem, because it can freeze out as ice in a filter, and the fuel is far thicker when cold, so the pumps have to be chosen for it. So the rig chills the whole loop evenly, insulates it to avoid cold spots, soaks it until the control system confirms that every sensor agrees, and only then lets fuel flow to the unit under test. This page states no soak time, because it depends on the volume, the fuel and the temperature, and belongs on the customer's own specification.

Q · 03 Why can heating fuel change the fuel?

Because hot fuel that carries dissolved oxygen oxidises, and the oxidation products can come out of solution as deposits on hot surfaces. Published research on jet fuel thermal stability describes this well: the deposits form on heated walls, they are worse when oxygen is present, and because they conduct heat poorly they foul heat exchangers and reduce how well those exchangers work. ASTM D3241, the jet fuel thermal oxidation test, is the public reference method for judging how readily a fuel forms them. For a fuel supply rig the consequence is practical: a heater that runs its metal surfaces much hotter than the fuel can create the very deposits that then change the fuel the unit under test receives. So the rig keeps its heated surfaces only slightly hotter than the fuel, keeps the fuel moving rather than standing, and blankets the fuel with nitrogen to keep oxygen out. The rig should deliver the fuel's condition, not create it.

Q · 04 Why measure the flow by mass rather than by volume?

Because what matters to an engine is the mass of fuel, and the density of fuel changes with temperature. The same volume of fuel weighs less when it is hot and more when it is cold, so a meter that counts volume reads a different amount for the same mass as the fuel warms or cools — exactly the range this rig is built to cover. A mass-flow meter of the Coriolis type measures the mass directly, and can report the fuel temperature at the same time. The rig therefore measures flow by mass, logs temperature and pressure beside it, and leaves the customer free to convert to whatever unit the test reports.

Q · 05 Is this the same as the aerospace fuel supply system page, or the pump and cooler test rig?

No, and the differences are worth stating precisely. The aerospace fuel supply system page describes a skid that delivers aviation fuel to engine and auxiliary power unit test cells at stable pressure, controlled flow and cleanliness — it is about the delivery, and it says nothing about temperature. The integrated test rig for pumps and fuel coolers page describes a bench that validates a specific set of aero engine components under real flow, pressure and thermal conditions — it is a test rig, built around those components. This page describes a different thing: the fuel source itself, with heating and chilling built in, that can supply any unit under test at a chosen temperature across the range from cold soak to hot fuel. It could sit in front of a test rig or a test cell; it does not replace either, and it does not claim what they do a second time.

Q · 06 Has Neometrix built one of these?

We would rather answer this plainly than let a page imply otherwise. Neometrix engineers heated and cold fuel supply rigs to order, and no delivered heated and cold fuel supply rig is claimed. What stands behind the offer is adjacent: Neometrix engineers the neighbouring pieces this rig is made of, including a skid-mounted fuel delivery system with filtration, regulation and metering (see the aerospace fuel supply system page) and a bench that runs aero engine components under real flow, pressure and thermal conditions (see the integrated test rig for pumps and fuel coolers page), together with the pressure-vessel, nitrogen and control engineering that ties them together. So the honest position is this: the rig is engineered to order, the neighbouring disciplines are in the building, and the first rig of this exact type will be built around a customer's fuel, temperature range and unit under test rather than lifted off a shelf.

Q · 07 Which standards apply, and who decides the test conditions?

ASTM D1655 is the public specification for aviation turbine fuel, and ASTM D3241 is the public test method for its thermal oxidation stability. ASME Section VIII is the public design code for pressure vessels, and the IEC 60079 series is the public reference for equipment in hazardous areas. None of them, on its own, sets the temperature range, the flow, the pressure or the soak for a specific test: those come from the unit under test and from the customer's own test specification, and they are not printed generically on a page like this one. Acceptance of the finished rig, including any temperature, flow and pressure checks before handover, rests with the customer and whatever inspection authority they name.

Q · 08 What do you need from us to quote?

Six things, and most of them describe the test rather than the rig. First, the fuel: its grade and any additives. Second, the unit under test: what it is and how it connects to the supply. Third, the temperature range: how cold and how hot the fuel has to go, and how quickly it has to change between them. Fourth, the flow and pressure the unit needs at each temperature. Fifth, the configuration: a single-loop skid, a dual-leg rig or a cell-integrated installation, and how often the test is run. Sixth, the site: the space, the utilities available for heating and chilling, and any hazardous-area rules that apply. From that we come back with a system definition you can check, a flow and layout drawing, and a budgetary price.

The other fuel test systems, and how they differ from this one.

Three neighbours in the same fuel-test family.

↗ The delivery skid

Aerospace Fuel Supply System

Skid-mounted fuel delivery for engine and auxiliary power unit test cells - stable pressure, flow and cleanliness, with no temperature conditioning.

↗ The component bench

Integrated Test Rig for Pumps and Fuel Coolers

A bench that validates aero engine pumps and fuel-cooled oil coolers under real flow, pressure and thermal conditions.

↗ The other fuel

Hydrogen Fuel System Component Test System

Type-qualification testing of hydrogen fuel-system components - a different fuel, with its own hazards.

Browse all Neometrix product lines.

Get a quotation

Tell us the fuel, the temperature range,
and what has to be tested on it.

The projects desk replies within two working days with a system definition you can check, a flow and layout drawing, and a budgetary quotation. Write to [email protected] or use the form.

Enquire — fuel supply rig Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — HEATED & COLD FUEL SUPPLY RIG FILL · CONDITION · SOAK · DELIVER · RETURN · MAKE SAFE — CONDITION THE FUEL, THEN TEST ENGINEERED IN NOIDA · INDIA