Spiral Wound M series are designed and manufactured for boiler manholes and handholes, valve bonnet covers etc. In required shapes and dimensions for service pressure range from 150LB to 2500LB. 1504-M is manufactured with SUS 304 and asbestos paper filler, and 1506-M with SUS316. 1509-M is manufactured with other metals on request.
Other asbestos free types are also available on request.
Service Temperature 1504-M: up to 500°C
1506-M: up to 580°C

The type without an inner ring can be used if the following conditions are fully satisfied.
Filler material: NA or asbestos
Pressure rating: Class 600 or below, or 40K or below.
Size: Nominal diameter 24B or below, or 600A or below.