Leader Blowdown Valve

The Leader Steel Parallel Slide Blow Off Valve (Figure No. BM 072) is engineered for boiler blow-down service and high-pressure steam operations. Built with a cast steel body, rack-and-pinion rack drive, renewable seats, and corrosion-resistant Ni-Cu alloy discs, this heavy-duty valve delivers tight sealing and self-cleaning action. It comes certified under Form III-C (Regulation 269) of the Indian Boiler Regulations (IBR).

Technical Specifications

Parameter	Specification
Figure Number	BM 072
Max Working Pressure	350 psig (24.1 bar) at 800°F (427°C)
Hydrostatic Shell Test	700 psig
Hydrostatic Seat Test	700 psig
Steam Seat Test	350 psig
Design Standard / Code	Indian Boiler Regulations (IBR)
End Connections	Flanged ends as per BS 10 Table J FF

Key Features & Design Highlights

Fluid Tightness Without Wedging: Maintains continuous tightness using an internal spring between the discs without relying on mechanical wedging action.
Self-Cleaning Slide Action: The parallel sliding disc motion wipes away dirt and foreign scale from the seating faces every time the valve is operated.
Rack & Pinion Drive: Rack and pinion mechanism allows full opening with just a half turn of the box key.
Safety Locking Guard: The gland functions as a key-locking guard that prevents key removal unless the valve is completely closed.
Renewable Seating: Features renewable Ni-Cu alloy (Lumina) seat rings and discs for superior erosion resistance.

Material Specifications

Part No.	Description	Material	Specification
1	Body	Cast Steel	ASTM A 216 Grade WCB
2	Body Seat Ring	Lumina	Ni-Cu Alloy
3	Female Disc	Lumina	Ni-Cu Alloy
4	Male Disc	Lumina	Ni-Cu Alloy
5	Spring	Carbon Steel	IBR Clause 307 to 314
6	Rack	Bronze	IBR Clause 282 (a) (iv) Gr. B
7, 13	Gasket	C.A.F.	IS 2712
8	Bonnet	Cast Steel	ASTM A 216 Grade WCB
9, 11	Bush	Bronze	IBR Clause 282 (a) (iv) Gr. B
10	Studs & Nuts	Carbon Steel	BS 916
12	Pinion	Bronze	IBR Clause 282 (a) (iv) Gr. B
14	Stuffing Box	Bronze	IBR Clause 282 (a) (iv) Gr. B
15	Packing	Graphited Asbestos	Standard Commercial Grade
16	Studs & Nuts for Stuffing Box	Carbon Steel	BS 916
17	Gland	Bronze	IBR Clause 282 (a) (iv) Gr. B
18	Studs & Nuts for Gland	Carbon Steel	BS 916

Dimensional Data

DN (mm)	NPS (Inches)	L (mm)	H (mm)	T (mm)	Item Code
25	1"	178	148	18	BM 072 AG
32	1-1/4"	191	165	22	BM 072 AH
40	1-1/2"	267	172	22	BM 072 AI
50	2"	305	197	25.4	BM 072 AJ
65	2-1/2"	330	208	28.6	BM 072 AK