China Double Block And Bleed Gate Valve Suppliers, Manufacturers, Factory

Double Block and Bleed Gate Valve

Why choose double block and bleed gate valve

DDB refers to the function of the valve to isolate the pressure at each inlet and empty the cavity between the valve seats. After releasing the cavity between the valve seats, the user can check out all the leakage sources on the valve seat without removing the valve from the pipeline. The choice of this kind of valve may be a requirement for operational safety factors, or it may be an area with extremely low tolerance for leakage and product fluid cleanliness, such as the natural gas industry. The double-closed double-bleed valve is characterized by two one-way valve seats. The two one-way valve seats can isolate the cavity between the valve seats and the pipeline pressure under the driven condition. If the pressure turns, the valve seat is forced to leave the valve body, so that the pressure in the valve body cavity is discharged to the piping system.

Material review of double block bleed gate valve

Part No	Part Name	Material
1	Body	WCB
2	Bottom	Q235A
3	Chock plug	35#
4	Slip	QT500+fluororubber
5	Plug	WCB
6	Bonnet	WCB
7	Packing gland	Q235A
8	Packing sleeve	2CR13
9	Yoke	WCB
10	Guide block	45#
11	Screw	45#
12	Stem	1CR13

Drawing of double bleed block gate valve

drawing of double block and bleed gate valve

Size table of DDB gate valve

Operated by manual
Size（In）	L	D	D1	D2	B	f	A	B	C	H	K	D0	Z-d
4	457	φ254	φ200	φ157	32	2	695	480	170	175	290	φ300	8-φ22
6	559	φ318	φ270	φ216	37	2	745	518	186	205	350	φ350	12-φ22
8	686	φ381	φ330	φ270	42	2	885	606	235	260	495	φ450	12-φ25

Operated by gear
Size(IN)	L	D	D1	D2	B	f	A	B	C	H	K	D0	Z-d
4	457	φ254	φ200	φ157	32	2	857	532	170	175	290	φ310	8-φ22
6	559	φ318	φ270	φ216	37	2	910	569	186	205	350	φ310	12-φ22
8	686	φ381	φ330	φ270	42	2	1011	621	235	260	495	φ310	12-φ22
10	826	φ445	φ387.5	φ324	48	2	1115	695	265	348	600	φ310	16-φ29
12	965	φ521	φ451	φ381	51	2	1201	731	315	398	670	φ310	16-φ22
14	854	φ584	φ514.5	φ413	54	2	1266	784	327	461	740	φ310	20-φ32
16	889	φ648	φ571.5	φ470	58	2	1625	940	432	510	810	φ460	20-φ35
18	1219	φ711	φ628.5	φ533	61	2	1982	1130	597	550	915	φ460	24-φ35
20	1219	φ775	φ686	φ584	64	2	1994	1130	610	590	940	φ460	24-φ35