Spirax Sarco Steam Jet Thermocompressor, Installation And Maintenance Instructions Manual

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IM-P493-01 EMM Issue 2 5
2. General product information
2.1 General description
The SJT Steam Jet Thermocompressor is designed having a fabricated metallic construction.
The Thermocompressor may (or may not) incorporate an 'Actuator assembly', a 'Positioner'
and an 'Air regulating set'. If the Thermocompressor is supplied complete with these
accessories, the reader will find the Instruction Manuals for these items to the rear of this
document.
An SJT Steam Jet Thermocompressor can be described as a particular type of Ejector. An
Ejector is a device in which steam under pressure is used to entrain a gas or vapour that is
at a lower pressure. Within the Body of the Ejector, the two gases become intimately mixed
and are subsequently discharged at a pressure that lies somewhere between the original
steam pressure and the pressure of the entrained gas or vapour.
When the gas being entrained is purely water vapour, the Ejector is referred to as a Steam
Jet Thermocompressor.
Standards
These products fully comply with the requirements of the European Pressure Equipment
Directive 97 / 23 / EC. The product is manufactured to ASME B31.3 mechanical design code.
Certification
This product is available with certification to EN 10204 3.1. Note: All certification / inspection
requirements must be stated at the time of order placement.
2.2 Materials
The materials of construction for an SJT depend upon the following:
a) The size of the SJT (reflects how the SJT is designed and made).
b) The Mechanical Design Temperature (MDT).
c)
The Minimum Metal Design Temperature (MDMT, not often specified).
The most common material of construction for Spirax-Sarco Limited's SJT is carbon steel.
Chrome Molybdenum materials are used for high temperature applications and occasionally
stainless steel grade 316L is employed. A carbon steel SJT tends to employ stainless steel
316L motive steam nozzles.
Component Carbon steel Stainless steel Gr. 316L Chrome Molybdenum
MDT
Mechanical
Design Temperature
up to and including
425 °C (797 °F)
up to and including
500 °C (932F)
above 425 °C (797 °F) up to
and including 570 °C (1058 °F)
Pipe
ASTM A106 Gr. B ASTM A312 TP 316L ASTM A335 P11
Fittings ASTM A234 WPB ASTM A403 WP 316L ASTM A234 WP11
Forgings
ASTM A105N or
ASTM A350 LF2N
ASTM A182 F316L ASTM A182 F11
Bar ASTM A350 LF2N ASTM A479 316L ASTM A739 B11
Plate ASTM A516 Gr. 70 ASTM A240 316L ASTM A387 Gr. 11
Flanges ASTM A105N ASTM A182 F316L ASTM A182 F11
Bolts ASTM A193 Gr. 7 ASTM A193 Gr. B8 ASTM A193 Gr. B16
Nuts ASTM A194 Gr. 2H ASTM A194 Gr. 8 ASTM A194 Gr. 4
Washers
ASTM F436 Gr. 8 or
BS 4320 Gr. 8 or
BS 3410 Gr. 8
ASTM F436 Gr. A2 or
ASTM F436 Gr. A4 or
BS 4320 Gr. A4 or
BS 3410 Gr. A2 or
BS 3410 Gr. A4
ASTM F436 Gr. A2 or
ASTM F436 Gr. A4 or
BS 4320 Gr. A4 or
BS 3410 Gr. A2 or
BS 3410 Gr. A4