Leak tests

G. Apeldoorn, P. Vankov

29.01.2004, NIKHEF

Leak tests 29.01.2004

Tests are based on using:

AFS 1400 – Bidirectional Mass Flow Meter

Characteristics of AFS 1400:

- dynamic range: 0.03 – 400 sccm

-Fast response time: 150 ms

-Calibrated & Temperature compensated (for air & Nitrogen)

-Digital output signal (RS-232)

(http://www.sensirion.com)

Leak tests 29.01.2004

Flowmeter

opened

F1: 1.023e-6 l/s

F2: -1.621e-7 l/s

F3: -1.391e-7 l/s

F4: 1.057e-7 l/s

Leak tests 29.01.2004

Flowmeter

shorted

F1: 1.014e-6 l/s

F2: -1.441e-7 l/s

F3: -1.244e-7 l/s

F4: 8.529e-8 l/s

Leak tests 29.01.2004

Flowmeter

Flowmeter

Temperatures

Leak tests 29.01.2004

Connection in series

“Brooks” mass flow controller

Leak tests 29.01.2004

Leak test of Module 5012 (5m prototype)

(N)

Flow meter

F1

Bubbler

(8 mbar)

closed

Module12

Steps:

0. Tap 2 is always closed.

1. Tap 1 is opened, gas is pumping the module in.

2. Tap 1 is closed, module is under 8 mbar overpressure, F1 is measuring.

Leakage criterion:

Leakage flow must be of the order (or less) of 1e-6 l/s.

Leak tests 29.01.2004

Leak tests 29.01.2004

Flow meter

F1

ModuleF2

Flow meter

straw

straw

straw

straw

outer

outer outer

outer

Gas

Gas volumes (straw/outer) separation

Leak tests 29.01.2004

Gas volumes (straw/outer) separation

Flow meter

F1

ModuleF2

Flow meter

straw

straw

straw

straw

outer

outer outer

outer

Gas

Leak tests 29.01.2004

How to proceed ?

-Better tubes & taps

-Atmospheric pressure & temperature monitoring

-Flow controller

-Nitrogen/Argon