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SEMI F43-0699 © SEMI 1999 9 A P PENDIX 1 SAMPLER DESIGN CRITERI A A-1. 1 The averag e velocity of g as flo w i n g t hrough the sampler should approx i mate the average velocity in the tubing in which the sampler is i ns…

SEMI F43-0699 © SEMI 1999 8

Table 1 Parts List for the Recommended Particle Test Apparatus

Item

number Description

1/4 in. diameter electropolished (EP) SS tube

1/4 in. to 1/2 in. tube reducing union

1/2 in. diameter EP SS tube

PTFE membrane filter with 3/8 in. face seal

Pressure regulator, 0-300 inlet pressure, 0-100 outlet pressure

1/2 in. butt weld tee

1/2 in. tube to 3/8 in. NPT female connector

0-60 psig electronics grade pressure gauge

1/2 in. to 1/2 in. union

1/2 in. 3-way SS ball valve

1/4 in. tube to 1/2 in. port reducer

0.2-2 std ft

flowmeter

1-15 std ft

flowmeter

1/2 in. SS union

1/2 in. dia, 3-ft flexible SS tube

1/2 in. union elbow

1/2 in. pneumatic valve

1/2 in. to 1/4 in. SS reducer gland

Test component

3-way normally closed solenoid air valve

Solenoid valve cycle controller

1/2 in. welded tee

1 1/2 in. dia., 4-ft long exhaust tube

1/2 in. tube to 1/4 in. NPT adapter

1/8 in. dia., 17 in. long SS sample tube

1/4 in. to 1/8 in. reducer union

1/4 in. dia., 30 in. long SS sample loop

1/4 in. to 3/8 in. reducer union

Condensation Nucleus Counter

SEMI F43-0699 © SEMI 19999

APPENDIX 1

SAMPLER DESIGN CRITERIA

A-1.1 The average velocity of gas flo wing through the

sampler should approximate the average velocity in the

tubing in which the sampler is inserted. The sample

flow rate used to calculate the sampler diameter is the

total flow drawn by the counter.

A-1.2 Gradual expansion to atmospheric pressure is

recommended for sampling. Critical orifice expansion

may alter the particle level of the sample.

A-1.3 The tip of the sampling probe should have a 30

degree taper on the outside diameter.

A-1.4 The pick-off point should be approximately

centered within the flow stream.

A-1.5 The pick-off point should be approximately 15

diameters of the primary flow tube upstream or

downstream of any connection.

A-1.6 There should be enough volume in the exhaust

portion of the sampler to supply the CNC for one

minute. This volume represents 60 times the volume

that will be drawn by the CNC while the valve is closed

during the dynamic testing. Minimum sample flow

through the CNC is 5 slpm.

A-1.7 State the minimum volume after the probe or

generate a sample blank using the stated volume until

background counts are reached.

Under static flow conditions, the sampler size is within

50% of the size required to achieve isokinetic sampling.

For particles of interest <0.5 um, Hinds

and Fissan

indicate that any unlikely isokinetic sampling biases are

significant. During dynamic testing, isokinetic

sampling is compromised regardless of the sample tube

size.

CNC

Isokinetic Sampler Calculation

To establish isokinetic sampling condition:

= V

Q = AV or V = Q/A

so Q

= Q

therefore, A

= A

) or D

= D

)

1/2

where:

Q = flow rate (volumetric)

A = area (internal cross section)

V = velocity (average)

D = diameter (internal)

subscripts:

1 = main flow line

2 = sample flow line

If pressure correction at point of flow control device is

needed, then:

= [(P + 14.7)/14.7]

1/2

x Q

where:

= actual flow rate

= standard flow rate

P = pressure, psig

Temperature variances are assumed to be negligible.

NOTICE: These standards do not purport to address

safety issues, if any, associated with their use. It is the

responsibility of the user of these standards to establish

appropriate safety and health practices and determine

the applicability of regulatory limitations prior to use.

SEMI makes no warranties or representations as to the

suitability of the standards set forth herein for any

particular application. The determination of the

suitability of the standard is solely the responsibility of

the user. Users are cautioned to refer to manufacturer’s

instructions, product labels, product data sheets, and

other relevant literature respecting any materials

mentioned herein. These standards are subject to

change without notice.

The user’s attention is called to the possibility that

compliance with this standard may require use of

copyrighted material or of an invention covered by

patent rights. By publication of this standard, SEMI

takes no position respecting the validity of any patent

rights or copyrights asserted in connection with any

item mentioned in this standard. Users of this standard

are expressly advised that determination of any such

patent rights or copyrights, and the risk of infringement

of such rights, are entirely their own responsibility.

International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o

the contents in whole or in part is forbidden without express written

consent of SEMI.

SEMI F44-0699

GUIDELINE FOR STANDARDIZATION OF MACHINED STAINLESS

STEEL WELD FITTINGS

This guideline was technically approved by the Global Facilities Committee and is the direct responsibility of

the Japanese Facilities Committee. Current edition approved by the Japanese Regional Standards Committee

on March 17, 1999. Initially available on www.semi.org May 1999; to be published June 1999.

1 Purpose

1.1 The purpose of this guideline is to prevent

confusion among the manufacturers of stainless steel

weld fittings, piping fabricators and end users and to

standardize the dimensions of weld fittings.

2 Scope

2.1 This guideline applies to 6.35 mm (1/4in.), 9.53

mm (3/8in.) and 12.7 mm (1/2in.); the machined

stainless steel weld fittings elbows and tees made for

use in the semiconductor industry.

3 Referenced Documents

3.1 None.

4 Terminology

4.1 elbow weld fittings  machined fittings shaped

like the letter "L", for welding tubes in a right angle.

(see Figure 1)

4.2 tee weld fittings  machined fittings shaped like

the letter "T", for welding tubes in a T-shape. (see

Figure 2)

4.3 weld fittings  machined fittings to be welded or

welded fittings.

Figure 1

Elbow Weld Fittings

Figure 2

Tee Weld Fittings

5 Dimensions of Weld Fittin gs

5.1 Elbow Weld Fittings (see Figures 3A and 3B)

5.2 Tee Weld Fittings (see Figures 4A and 4B)

Figure 3A

Dimensions of Elbow Weld Fittings

NOTE 1: Machined tube weld ends shall be square tolerance ±

0.5°.

NOTE 2: Intersection shall be square tolerance ± 0.5°.