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金属密封球阀

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钛波纹管调节阀

详细信息

Kv coefficient calculation

Calculation itself is carried out with respect to conditions of regulating circuit and operating medium according to equations mentioned below. Control valve must be designed to be able to regulate maximal flow quantity at given operating conditions. At the same time it is necessary to check whether minimal flow quantity can be even regulated or not.

Condition is the following ratio

r > Kvs / Kvm

Because of eventual minus tolerance 10% of Kv100 against Kvs and requirement for possible regulation within range of maximal flow (decrement and increase of flow), producer recommends to select Kvs value higher than maximal operating Kv value:

Kvs = 1.1 1.3 Kv

It is necessary to take into account to which extent Qmax involve precautionary additions" that could result in valve oversizing.

Relations of Kv calculation

Above critical flow of vapours and gases

When pressure ratio is above critical (p2 / p1 < 0.54), speed of flow reaches acoustic velocity at the narrowest section. This event can cause higher level of noisiness. Then it is convenient to use a throttling system ensuring low noisiness (multi-step pressure reduction, damping orifice plate at outlet).

Flow characteristic selection in regard of valve stroke

To make right selection of valve flow characteristic, it is suitable to carry out checking of what stroke values will be reached in different o peration states. We recommend to carry out such checking at least for minimal, nominal and maximal flow rates. The principle for flow characteristic selection is to avoid, if possible, 5 10% of the beginning and end of the valve stroke range.

To calculate valve stroke at different operating conditions with different types of flow characteristics is possible with the advantage of using LDM´s calculation program me VALVES. The program me serves for complete design of valve from Kv calculation to specification of a concrete valve with its actuator.

Valve flow characteristics

Dimensions and units

Principles for plug type selection

1

V-ported plugs should not to be used in above - critical differential pressures with inlet pressure p >= 0,4 MPa and for regulation of saturated steam. In these cases we recommend to use a perfo- rated plug.The perforated plug should be also used always when cavitation may occur due to a high differential pressure value or valve ports erosion caused by high speed of process medium flow. If the parabolic plug is used (because of small Kvs) for above-critical differential pressures, it is necessary to close both plug and seat with a hard metal overlay, i.e. stellited trim.

Packing – Bellows

Bellows packing is suitable for low and high temperatures ranging from -50oC to 550oC. Bellows ensures absolute tightness to environment. Packing is equipped with safety PTFE packing as standard to prevent medium from leaking in case of damage to bellows. Intensive linear forces are not required.

Application of bellows packing

Bellows packing is suitable for applications with very aggressive, toxic or other dangerous media that require absolute tightness to environment. In such case, it is necessary to check compatibility of used body material as well as the valve inner parts material with process medium. It is recommended to use bellows with safety packing preventing medium from leaking in case of damage to bellows when there is an extremely dangerous process medium used.

Bellows is also a great solution to use of process medium either with temperature below zero when ice accretions cause premature damage to packing or with high temeperatures when bellows ensures medium cooling.

Service life of bellows packing

Values specified in the table above show minimal guaranteed number of cycles with the valve full stroke when the bellows is fully lenghtened and pressed. In regulation, when the valve moves only in a portion of the stroke range at the inner centre of the valve, the service life of the bellows is many times longer then depending on concrete operating conditions.

Standard specificoatins BODY

Series		WT2510B
Body size		20mm-200mm
Flange standards		ANSI B16.5 RF
Operating Temp.		-50℃ to 550℃
Special Cleaning for Body		Oxygen clean,Oil-free,Water-free
Materials	Body	WCB
	Ball	HC
	Stem	HC
	Seal ring	PTFE

Attention:

1.Before installed onto pipes, the product shall always be packaged.

2.Speed controller has been adjusted befor shipment,Please don't adjust it.

3.Body Inseat Has been adjusted in a good position when it leaves the factory, not adjustable .

Cv AVLUE,STROKE AND REDUCED PLUG MANUFACTURING RANGE

FLOW CHARACTERISTICS

Body section view

DIMENSIONS

D		20	25	32	40	50	65	80	100	125		150	200
φA		285					360			470
L	CLASS 150lb	184	184	222	222	254	276	298	352	425	451		543
L	CLASS 300lb	194	197	235	235	267	292	317	368	425	472		568
D1	CLASS 150lb	100	110	120	130	150	180	190	230	255	280		345
D1	CLASS 300lb	120	125	135	155	165	190	210	255	280	320		380
D2	CLASS 150lb	70	79.5	89	98.5	120.5	139.5	152.5	190.5	216	241.5		298.5
D2	CLASS 300lb	82.5	89	98.5	114.5	127	149	168.5	200	235	270		330
D3	CLASS 150lb	52	57	66.5	73	92	104.6	127	157	185	216		270
D3	CLASS 300lb	52	57	66.5	73	92	104.6	127	157	185	216		270
B	CLASS 150lb	13	14.5	16	17.5	19.5	22.5	24	24	24	25.5		29
B	CLASS 300lb	16	17.5	19.5	21	22.5	25.5	29	32	35	37		41.5
f	CLASS 150lb	-	6.3	6.3	6.3	6.3	6.3	6.3	6.3	-	6.3		6.3
f	CLASS 300lb	6.3	6.3	6.3	6.3	8	8	8	8	-	8		8
n	CLASS 150lb	4	4	4	4	4	4	4	8	8	8		8
n	CLASS 300lb	4	4	4	4	8	8	8	8	8	12		12
φ	CLASS 150lb	16	16	16	16	18	18	18	18	22	22		22
φ	CLASS 300lb	18	18	18	22	18	22	22	22	22	22		26
H1	CLASS 150lb	53	58	70	75	83	93	100	110	123	143		170
	CLASS 300lb	53	58	70	75	83	93	100	118	135	150		188
H	Bellows	442	454	500	548	538	640	723	731	970	1023		1116

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