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NPT Series

NPT fusible plug

We are able to produce any fusible plugs according to customer specifications including thread type and sizes, plug body material, etc. In practice NPT fusible plugs of the following sizes and yield temperatures are considered to be standard models due to their popularity in application. These plug bodies, both brass and stainless steel, are often in stock, resulting in shorter delivery times.

Standard Model List
#

°F °C 1/8″NPT 1/4″NPT 3/8″NPT 1/4″NPT 1/4″NPT 3/8″NPT 1/2″NPT
Brass Brass Brass Brass SS SS SS
136 58 AQS18-58 AQS14-58 AQS38-58 AQS12-58 AQS14-58SS AQS38-58SS AQS12-58SS
160 71 AQS18-71 AQS14-71 AQS38-71 AQS12-71 AQS14-71SS AQS38-71SS AQS12-71SS
165 74 AQS18-74 AQS14-74 AQS38-74 AQS12-74 AQS14-74SS AQS38-74SS AQS12-74SS
180 82 AQS18-82 AQS14-82 AQS38-82 AQS12-82 AQS14-82SS AQS38-82SS AQS12-82SS
195 90 AQS18-90 AQS14-90 AQS38-90 AQS12-90 AQS14-90SS AQS38-90SS AQS12-90SS
212 100 AQS18-100 AQS14-100 AQS38-100 AQS12-100 AQS14-100SS AQS38-100SS AQS12-100SS
230 110 AQS18-110 AQS14-110 AQS38-110 AQS12-110 AQS14-110SS AQS38-110SS AQS12-110SS
255 124 AQS18-124 AQS14-124 AQS38-124 AQS12-124 AQS14-124SS AQS38-124SS AQS12-124SS
281 138 AQS18-138 AQS14-138 AQS38-138 AQS12-138 AQS14-138SS AQS38-138SS AQS12-138SS
361 183 AQS18-183 AQS14-183 AQS38-183 AQS12-183 AQS14-183SS AQS38-183SS AQS12-183SS
390 199 AQS18-199 AQS14-199 AQS38-199 AQS12-199 AQS14-199SS AQS38-199SS AQS12-199SS
450 232 AQS18-232 AQS14-232 AQS38-232 AQS12-232 AQS14-232SS AQS38-232SS AQS12-232SS

Dimensions
#

drawing of NPT fusible plug
Thread Size H(mm) T(mm) S(mm) Orifice(mm)
1/8"NPT 16 5 12 5
1/4"NPT 21 6.5 14 5
3/8"NPT 20 6 17 6
1/2"NPT 29 8 22 85

Product Specifications
#

  • Tolerance of yield temperature: ±3°C
  • Plug body material: brass / stainless steel
  • Eutectic alloy consisting of multiple components
  • Test pressure: 3.0 MPa (higher pressure upon request)
  • Max service pressure: 5 MPa for brass, 15 MPa for stainless steel
  • HS code: 8481809000