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INSPIRATORS - SPI TYPE

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Our SPI range of atmospheric inspirators are manufactured from aluminium with brass injectors.They are an economical design and would be preferred over the LPI type if space were limited.

Inspirators have two main purposes. They are primarily designed to accurately mix gas and air in the correct proportions and deliver the resulting mixture to an appropriate burner unit. They can also be used as "economisers", inspirating atmospheric air from the venturi effect of the air stream. This arrangement can save up to 5 parts of air.

Although chiefly intended for low pressure gasses, the SPI are equally suitable for higher pressures due to the fine throat design. For correct inspiration it is important to ensure the throat size is matched to the burner port area. Flash back, pulsing, inability to achieve a stable oxidising flame or lack of forward velocity will indicate the burner port area and the inspirator throat are not an ideal match. Try a smaller inspirator relative to the burner head pipe size, if higher pressure gas is used, for better results.

PART NUMBER

THREAD SIZE BSP

DIMENSIONS (mm)

WEIGHT kg

THROAT AREA (mm2)

INLET

OUTLET

LENGTH

DIAMETER

SPI15

8mm

15mm

80

49

100g

108

SPI20

8mm

20mm

107

53

200g

230

SPI25

8mm

25mm

122

70

250g

495

SPI32

15mm

32mm

150

86

450g

669

SPI40

15mm

40mm

175

90

600g

860

SPI50

20mm

50mm

195

115

950g

1665

SPI65

20mm

65mm

255

145

2.55

2300

SPI80

20mm

80mm

255

145

2.1

3310

The orifice is accurately machined and carefully aligned with the throat for high inspiration rates. The SPI15, SPI20 and the SPI25 have one piece spuds, the other sizes are available with a separate orifice. All inspirators are supplied with a pilot hole drilling as standard unless a size is specified.

CAPACITIES

The capacity of an inspirator is dependent on many factors such as the type of burner, furnace pressure conditions and the gas type and pressure. Low pressure atmospheric burners rely on secondary air and capacities can be increased by up to 300% if sufficient draw is available. The following chart is an approximation only and relates to low pressure Natural Gas with a H.V. of approx. 38 MJ/m3. It is recommended you follow the AN burner tip chart for typical capacities under a variety of conditions. The matching SPI inspirator and AN tip can be used in tandem for a suitable low pressure, gas torch burner.

The SPI inspirators are also equally suitable matched to an FR tip for a higher gas pressure high capacity torch providing the port area/throat area ratio is maintained.

APPROXIMATE CAPACITIES AT VARIOUS GAS PRESSURES

PART NUMBER

1 kPa

1.5 kPa

3 kPa

SPI15

10

12

17

SPI20

22

27

38

SPI25

35

42

60

SPI32

50

60

86

SPI40

70

85

120

SPI50

110

135

190

SPI65

175

210

300

SPI80

250

300

425

All capacities are shown in MJ/HOUR. 

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