Neometrix / Valve Test & Certification Systems / Engine Anti-Ice and Bleed-Air Valve Test Rig / NMX-BAV-35

NMX-BAV-35 · ENGINEERED-TO-ORDER CLASS — HOT AIR · CLAMP · COMMAND · MEASURE

Engine Anti-Ice and Bleed-Air Valve Test Rig. A valve that lives in hot air is not tested until it has been tested in hot air.

Name: Engine Anti-Ice and Bleed-Air Valve Test Rig
SKU: NMX-BAV-35

An engine anti-ice valve takes hot air from the compressor and sends it to the parts that would otherwise ice up. It does that in the hottest, most pressurised air on the engine. A bench that tests it in cold, gentle air is answering a different question.

So this rig makes hot, pressurised air, clamps the valve in it, commands the valve and measures what it does: whether it opens, how fast, and whether it shuts tight.

Discuss a valve test rig Capability note (PDF)

A hot-air valve test rig on a workshop floor: an upright stainless steel air heater wrapped in silver insulation, a valve in a grey steel test fixture joined to it by insulated pipes, and a plain grey instrument cabinet, and no people

Fig · 01 — A valve test rig on a workshop floor: an insulated air heater, a valve in its test fixture joined to it by insulated pipes, and a plain grey instrument cabinet — illustrative render.

The air

hot and pressurisedmade on the bench, on demand

The valve

clamped and commandedas it would be on the engine

The questions

open, fast, tightthe same three, cold and hot

The record

logged on one clockpressure, heat, flow, position

Status

engineered to orderno rig yet delivered

ISO 9001ISO 14001ISO 5208 valve pressure-test referenceISO/IEC 17025 calibration reference

Overview

Why the test has to be hot, and not only pressurised.

Because temperature changes how a valve seals, moves and responds, so a pass in cold air is a pass in the wrong conditions.

Fig · 02 — The rig in one picture: hot air feeds the valve, the valve is measured, and safety and control stand behind the air and the valve.

A valve tested cold has only been tested cold.

What the rig is for

It tests the valves that take hot compressed air off an engine and send it where it is needed: anti-ice valves and bleed-air valves. It is used when a valve has been overhauled, repaired or received, before it goes back on an engine.

Why an anti-ice valve matters

It protects the engine inlet from ice by delivering hot air on command. If it will not open, ice can build. If it will not close, or leaks when closed, air is bled away for nothing, the engine loses efficiency, and hot air can reach parts that were never meant to see it.

Why cold is not enough

A valve is made of parts that grow, harden and soften at different rates as they heat. Seals behave differently when hot. A difference in expansion between the body and its cover can open a leak path that a cold test never sees.

Why the rig makes its own air

A bench needs air at the valve's conditions, steadily and on demand, without an engine running. So the rig has its own compressed air, heater, regulators and instruments. The heater is always kept in flow, because a heater run without flow overheats.

Why there are only three questions

Does it open when commanded? How fast does it act? Does it shut tight? Everything else the rig measures is a way of answering those three.

Why the record is the product

Pressure, temperature, flow, valve position and the command are logged on one clock. The response time and the leakage are worked out from data, not from a person watching a gauge.

The test

Clamp, baseline, heat, command, seal, cycle and record.

Six steps in a fixed order. The valve is run cold first, so that the hot result has something to be compared with.

FIG · 02ENGINE ANTI-ICE AND BLEED-AIR VALVE TEST RIG · CLAMP / BASELINE / HEAT / COMMAND / SEAL / CYCLE & RECORD — THE VALVE IS TESTED IN THE AIR IT LIVES IN

The step people underrate is the baseline. Without a cold run to compare against, a hot result is a reading with nothing to be compared to.

Fig · 03 — Three ways an anti-ice valve can fail: stuck closed, so no hot air reaches the inlet; stuck open, so air is bled away; and leaking when closed, the same loss made slowly — a drawing of the idea, with no values.

1 · Clamp

The valve is fitted to a fixture with the same connections it has on the engine, and its command and position leads are joined up.

2 · Baseline

The valve is first run in cold, gentle air, so that everything measured later can be compared with how it behaved before it was heated.

3 · Heat

The rig brings the air to the valve's conditions, steadily, and then leaves the valve to soak until it is hot right through.

4 · Command

The valve is commanded open and closed. The rig times how long each takes and records where the valve actually goes.

5 · Seal

With the valve closed, pressure is held on one side and any air that passes is measured on the other.

6 · Cycle & record

The valve is cycled, and every result is logged against the valve's own limits and issued as a report.

Work content

What the rig contains, element by element.

Read it as a checklist: a rig missing a row will be corrected later, usually by a test result that nobody can trust.

A metal valve with a round actuator clamped between two silver-insulated pipes in a grey steel cradle on a steel bench, with a thin cable and two thin stainless tubes leading away from it, and no people

Fig · 04 — The valve fixture: a valve with a round actuator, clamped between two insulated pipes in a steel cradle, with a cable and two instrument tubes leading away — illustrative render.

Element	What it does	What matters
Compressed air supply	provides the air the valve breathes	clean and dry, so nothing fouls the seals
Air heater	brings the air to the valve's conditions	protected against running without flow
Pressure & flow regulation	holds the test conditions steady	steady at every step and in every state
Insulated hot lines	carry the hot air safely	insulated to protect people and instruments
Valve fixture	holds the valve as it sits on the engine	the same connections, mounted the same way
Command & position interface	operates the valve and reads where it is	electrical and pneumatic commands, with position fed back
Instrumentation	measures pressure, temperature, flow and time	calibrated, with traceable records
Leakage measurement	measures the air passing a closed valve	a sensitive flow meter on the far side
Exhaust & silencer	dump the used hot air	quiet, and directed away from people
Relief & interlocks	protect people and the rig	overpressure relief, guards and stop conditions
Control & data acquisition	run the sequence and log everything	the same sequence every time, with limits from the valve's own manual
Testing & documentation	prove the rig, then each valve	a calibrated rig, and a report for every valve

The element that decides whether a result can be trusted is not a machine. It is the baseline. A hot test with no cold run beside it can be repeated, but it cannot be compared.

Fig · 05 — One valve, three conditions it is tested in: cold and gentle, hot and pressurised, and hot after many cycles.

Full specification — expand

Rig	A compressed air supply; an air heater protected against running without flow; pressure and flow regulation; insulated hot lines; a valve fixture that holds the valve as it sits on the engine; a command and position interface; calibrated instrumentation for pressure, temperature, flow and time; a leakage measurement on the far side of the closed valve; an exhaust and silencer; relief and interlocks; a control and data acquisition system; and testing and documentation before handover
The One Idea	A valve that lives in hot air is not tested until it has been tested in hot air, so the rig makes the hot air and asks the valve the same three questions as in cold air
Why Hot	A valve is made of parts that grow, harden and soften at different rates as they heat, seals behave differently when hot, and a difference in expansion between the body and its cover can open a leak path that a cold test never sees
Why the Valve Matters	An anti-ice valve delivers hot compressor air to the engine inlet on command; if it will not open, ice can build, and if it will not close or leaks when closed, air is bled away for nothing, efficiency falls and hot air can reach parts not built for it
Why Its Own Air	The rig makes hot, pressurised air steadily and on demand, so a valve can be tested without an engine running, and the heater is kept in flow so that it is never allowed to overheat
The Three Questions	Does it open when commanded, how fast does it act, and does it shut tight
The Record	Pressure, temperature, flow, valve position and the command are logged on one clock, so response time and leakage are worked out from data and not from a person watching a gauge
Standards	ISO 5208 is the public reference for how the pressure testing and leakage of valves is described, ISO/IEC 17025 for calibration, and ISO 9001 for the quality system. None of them sets the limits for a particular valve: those come from the valve's own maintenance documents and are set by the customer. Acceptance of the finished rig rests with the customer and their inspection authority
Configurations	A bench rig for one valve type on one fixture, a multi-valve rig with fixtures for several valve types on one air supply, and a rig with a cold chamber so the valve can be cold outside while hot air runs inside
Scope Boundary	This is the rig that tests the valves which take hot air off an engine. It is not a whole environmental control system bench (see ECS test bench), not hot-oil testing of hydraulic valves (see aircraft servo valve hydraulic test equipment) and not a flow-coefficient rig for industrial control valves (see CV and control valve test rig)
Status	Neometrix engineers engine anti-ice and bleed-air valve test rigs to order, and no delivered engine anti-ice and bleed-air valve test rig is claimed.

Configurations

One method, three ways to supply the rig.

The steps, the three questions and the record are shared. What changes is how many valve types the rig serves, and what surrounds the valve while it is tested.

Bench rig

One valve type, one fixture

A fixed rig with a fixture for the valve on the customer's list, for a workshop that overhauls one kind of valve.

Multi-valve rig

Several valve types, one air supply

One hot-air source serving fixtures for several valve types, so that a different valve can be prepared while the last one is on test.

Rig with a cold chamber

Hot air inside, cold outside

A chamber around the valve, so that it can be cold-soaked on the outside while hot air runs through it, as it does when ice is forming.

Fig · 06 — Three ways to supply the rig, one method: a bench rig, a multi-valve rig, or a rig with a cold chamber.

And the part that is not equipment at all, yet decides all three: the test procedure — the written sequence, the limits taken from the valve's own manual, and the rule for reading the leakage, so that every valve is judged the same way.

Where it is used

Wherever a valve has to be trusted before it goes back on an engine.

The common thread is a valve that has been taken off, worked on or received, and must be proved in the air it lives in.

Overhaul workshops

Where a valve comes back from repair and has to be proved before it is issued.

Incoming inspection

Where a valve is received from stores or a supplier and is checked before it is fitted.

Fault investigation

Where a valve removed for a fault is run on the bench to see what it does.

New or indigenised valves

Where a valve made to replace an imported one is proved in the conditions of the engine.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 Why must an anti-ice valve be tested in hot air?

Because a valve is not the same machine hot as it is cold. Its parts are different materials, and they grow, harden and soften at different rates as they heat. A seal that is soft and tight in a cold test can behave differently at temperature. A difference in expansion between the body and its cover can open a leak path that only exists when the valve is hot, and the moving parts can bind or free up as the clearances change. Published experience with valves in hot service points the same way: leakage at operating temperature is not the leakage at ambient temperature. So the rig makes hot air, lets the valve soak until it is hot right through, and only then asks it the same three questions it was asked cold. This page states no temperature or pressure, because they belong to a particular valve and engine.

Q · 02 What does an anti-ice valve do, and what goes wrong when it fails?

It controls the supply of hot air, taken from the engine compressor, that keeps the inlet of the engine free of ice. There are three ways it can fail. If it will not open when it is commanded, the inlet is left unprotected and ice can build on it. If it will not close, the compressor keeps giving up air for nothing, the engine loses efficiency, and the hot air can damage parts of the engine that were never meant to see it. If it leaks when closed, it does the same thing slowly, which is harder to notice. Engine designs differ in whether the valve is held open or closed when it has no command, so the position it falls back to is one of the things the test proves.

Q · 03 Why does the rig make its own hot air instead of using an engine?

Because a workshop bench has to be repeatable, safe and available on demand, and an engine is none of those. The rig has its own compressed air supply, its own electric heater, its own regulators and its own instruments, so the same air can be made again for the next valve. A heater has one rule that a good rig obeys without exception: it must never run without air flowing through it, or its elements overheat. So the rig keeps a minimum flow through the heater at all times, watches its temperature against limits, and shuts it down if either fails. The air then goes through insulated lines to the valve, and the used hot air goes to an exhaust with a silencer, away from people.

Q · 04 How are the three questions measured?

Does it open? The rig commands the valve and reads its position back, so the valve is judged by where it went and not only by whether the command was sent. How fast? The time from the command to the position is recorded on the same clock as the pressure, so the opening time and the closing time come from data. Does it shut tight? With the valve closed, pressure is held on one side and the air that gets through is measured on the other, on a flow meter sensitive enough for a small leak. The rig also records the pressure lost across the valve when it is open, which shows whether it passes the air it should. Every result is set against the limits in the valve's own maintenance documents.

Q · 05 Is this the same as the ECS test bench, the servo valve equipment or the control valve rig?

No, and the differences are worth stating precisely. The ECS test bench is a bench for a whole environmental control system, fed with simulated bleed air; this page tests the valves that take the bleed air off the engine. The aircraft servo valve hydraulic test equipment page is about hydraulic valves tested with hot oil, not hot air. The CV and control valve test rig page is a flow-coefficient rig for industrial control valves. This page does not replace any of them, and it does not claim what they claim 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 engine anti-ice and bleed-air valve test rigs to order, and no delivered engine anti-ice and bleed-air valve test rig is claimed. What stands behind the offer is adjacent: Neometrix engineers hot-air supply and measurement on a bench for a whole environmental control system (see the ECS test bench page), hot-medium testing of valves under thermal and pressure conditions (see the aircraft servo valve hydraulic test equipment page), and pressure-drop and flow measurement on valves (see the CV and control valve test rig page). The compressors, air heaters, regulators, flow meters and transducers are proven catalogue items and are chosen with the customer, not invented. What Neometrix engineers is the air circuit, the fixtures, the control sequence, the safety system, the data record and the documentation. So the honest position is that the rig is engineered to order, the neighbouring disciplines are in the building, and the first rig of this exact kind will be built around the customer's valves and limits rather than lifted off a shelf.

Q · 07 Which standards apply, and who sets the limits?

ISO 5208 is the public reference for how the pressure testing and leakage of valves is described, including how leakage is measured on the far side of a closed valve. ISO/IEC 17025 is the public reference for the competence and traceability of calibration, which is what makes the rig's instruments trustworthy. Neither of them sets the limits for a particular valve. Those come from the valve's own maintenance or overhaul documents, and they are set by the customer, so this page prints none of them. Acceptance of the finished rig, including its proving tests 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 valve rather than the rig. First, the valves: which types, with their drawings and maintenance documents. Second, the air: the conditions each valve sees on the engine, and the range the rig must cover. Third, the tests and limits: which questions, in which order, and the limits each valve must meet. Fourth, the interfaces: how each valve is commanded and how its position is read. Fifth, the configuration: a bench rig, a multi-valve rig, or a rig with a cold chamber. Sixth, the site: the power, compressed air and floor space the workshop can offer. From that we come back with a layout drawing, a written test procedure you can check, and a budgetary price.

The neighbouring test benches, and how they differ from this one.

Three neighbours in the same family of air, valve and engine test equipment.

↗ The whole system

Environmental Control System (ECS) Test Bench

A bench that simulates hot bleed air and validates a whole environmental control system, not the valves that supply it.

↗ Hot oil, not hot air

Aircraft Servo Valve Hydraulic Test Equipment

Hydraulic servo valves proved with hot oil under thermal and pressure conditions.

↗ Flow coefficient

CV and Control Valve Test Rig

A flow-coefficient and pressure-drop rig for industrial control valves.

Browse all Neometrix product lines.

Get a quotation

Tell us the valve, the air it sees,
and the limits it must meet.

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

Enquire — valve test rig Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — ENGINE ANTI-ICE AND BLEED-AIR VALVE TEST RIG CLAMP · BASELINE · HEAT · COMMAND · SEAL · CYCLE & RECORD — THE VALVE IS TESTED IN THE AIR IT LIVES IN ENGINEERED IN NOIDA · INDIA