II500.50r4en - Valves General Recommendations

7/25/2019 II500.50r4en - Valves General Recommendations

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II500.50/4en

CCI 2006

Installation instructionsValves

General recommendations


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1 - Installation instructions

II500.50/4en Installation instructions Valves 1CCI

1 Installat ion instructions

1.1 Installation

1.1.1 Welding into piping system

The valve can be welded into the pipeline system with plug and

bonnet mounted with the restriction that the temperatures given in

fig. 1 will be kept.

The water injection loaded nozzles, type OP, installed in the valve

outlet shall always be removed before the PWHT of the valve weld

joint. The water connection pipe shall be connected to the water loop in such

a way that the motion caused by the thermal expansion of the steam

valve can take place without any forces being transferred to the water

loop.

Af ter welding, always make sure that no foreign particles have

entered the pipe and valve.

Cleaning of valve and piping system - see SI500.10.

Preheating, selection of welding electrode and heat treatment must be

performed in accordance with the welding instructions for the topical

material.

Measure and check the temperature at A shown below, during pre-

heating and welding - see fig. 1.


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2 Installation instructions Valves II500.50/4enCCI

We recommend you to use a GTAW (Gas Tungsten Arc Welding) for the

root pass. In doubtful cases, please contact BTG.

Always ground the welding machine on the piping side - not on thevalve body!

1.1.2 Inspection before reassembly

The following check routines are appropriate after e.g. clean blowing of

the valves.

Check all mating surfaces for damages.

Recondition by lapping with carborundum, if necessary (e.g. blend-in

scratches or indentations due to clamped-in foreign particles).

Check sealing surfaces with blue ink. The contact surface must be

Fig 1 Max. recommended

temperature during

preheating and

welding

A

A

Material invalve body

Max.temperature

(at point A)

Carbon steel (1) 480C/900F

Low alloy steel (1)

13CrMo4-5ASTM GR. 12

11CrMo9-10ASTM GR. 22

X10CrMoVNb 9-1ASTM GR. 91

580C/1075F

Low alloy steel (2)

X10CrMoVNb 9-1ASTM GR. 91

650C/1200F

(1) Internals are Tenifer surface hardened.(2) Internals are Cobolt hardfaced.


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II500.50/4en Installation instructions Valves 3CCI

intact around the seat periphery.

Visually inspect all internal parts to be assembled.

1.2 Cleaning of piping system (SI500.10)

This instruction describes number of alternative cleaning methods

designed for use in steam pipe systems which include control valves and

stop valves at different occasions, i.e. between and after machining and

before assembly or final installation. The cleanliness requirements are

primarily applicable at the time of final installation, but must be taken

into account during manufacture and sub-assembly.

The following cleaning methods are described in SI500.10:

Organic degreasing

Alkaline degreasing

Pickling

Blasting

Wire brushing

Steam blasting

BTG can, on request, supply s team blowing accessories see data

sheet D5001.

1.2.1 Acid cleaning of the piping system

The valve is resistant to most of the usually applied acid detergents, if

flushing starts immediately after the cleaning process.

Certain acid cleaning processes necessitate removal of acid-sensitive

valve parts. The responsibility and decision about this has to be borne by

the acid cleaning company.

In all cases, the gland packing material has to be removed, theglands to be flushed and cleaned properly and new packings mustbe installed after each acid cleaning.

(The packings may retain a small amount of acid, which may lead to stem

corrosion later on).

Service and maintenance of Grafoil stem seals - see SI500.11.

1.3 Protection of the spray water system

It is recommended to install a filter (100 m) in the spray water systemupstream of the valve to prevent plugging and wear.


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4 Installation instructions Valves II500.50/4enCCI

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II500.50r4en - Valves General Recommendations