06. September 2015 · Comments Off · Categories: Butterfly valves

Flanged and clip closure connection and adjust the flow with the flue butterfly valves are available in nominal pressure ≤PN0.6MPa, nominal diameter ≤DN3000mm, temperature ≤450 ℃, the medium is air, flue gas dust and gas and other industries.

Flue butterfly valve is suitable for adjusting the flow rate within the specified range and the closure.Flue butterfly valve compared with metal seal butterfly valve, butterfly valve in the conditions of use, structure and technical requirements, and leak rate test and test methods are different.

Metal seal butterfly valve minimum standard E-class gas maximum allowable leak rate: 200 × DN (mm3 / s).
Butterfly valve highest standards of A-level flue gas maximum allowable leak rate: L 0 = K × DN2 × √P × 10-6
Where L 0 — maximum allowable leakage rate, Nm3 / h.
K — A level leak factor
DN — butterfly valve nominal diameter, mm
P — test pressure, MPa.
From the above analysis standards and formulas, flue butterfly valve A level leak rate significantly higher than standard metal seal butterfly valve leak rate E-class standards. In the butterfly valve DN1200 caliber, for example, metal seal butterfly E-class standard maximum allowable leak rate
200 × DN = 200 × 1200
= 240 000mm 2 / s
= 0.014 4m3 / min
A level standard flue butterfly maximum allowable leak rate (according to 0.6MPa Nominal)
L0 = K × DN2 × √P × 10- 6
= 7.3 × 12002 × √600 000 × 10 – 6
= 8143Nm3 / h
= 136Nm3 / min
Analysis by the formula, flue butterfly valve and metal seal butterfly valve on the structural design and test methods are different, the flue butterfly valve sealing requirements significantly lower metal seal butterfly valve, its regulation characteristics similar to metal seal butterfly valve.

What are the technical requirements of the flue gas butterfly valves?
Flue gas butterfly valve flange dimensions, the sealing surface in the form of both ends of the flange bolt holes d0 axis with respect to the flange of the position tolerance, the minimum length of the structure and the valve seat diameter bore axis is to follow certain standards and technical requirements.

Flue gas butterfly valve flange dimensions and sealing surface in the form of regulations according to API609, and flue gas butterfly valve flange sealing surface should be perpendicular to the channel axis, coaxial with the axis should smoke butterfly valve channel, flange sealing surface should be parallel to each other at both ends of its axis its parallelism by API609 accuracy, connecting flange structure according to the need to allow the bolt hole threaded flange bolt holes at both ends of the axis relative to the flange d0 position tolerance bore axis as defined, the flange connecting flue gas butterfly valve structural length required to API609, and to connect the flue gas butterfly valve clip length of the structure in accordance with the provisions of API609, the nominal diameter of 2000 mm greater than the length of the flue gas butterfly valve structure according to user requirements to determine the seat of the minimum diameter It shall not be less than the specified.
Should you want to know more about butterfly valve from Reliable China valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

31. August 2015 · Comments Off · Categories: Butterfly valves

The majority of our butterfly valve product testing factory inspection and type test is divided into two categories. Butterfly valve type of inspection refers to conduct a comprehensive assessment of product quality butterfly valve, namely technical requirements specified in the standard are fully test (if necessary, but also increase test items), called type test, also known as routine tests.
1)When one of the following circumstances, butterfly valve type inspection should be carried out in general:
(1)New products or old products to the plant trial to identify stereotypes for the butterfly valve;
(2)The official production, such as structure, materials, technology has drastically changed, which may affect the valve performance;
(3) Normal production, after regular or accumulate a certain output, a test should be carried out periodically;
(4) Butterfly valve long shutdown, resume production;
(5) The factory test results and the last type testing when there is a big difference;
(6) The State Administration of Quality Supervision bodies type inspection requirements.

Check butterfly valve type test taken from the factory quality inspection departments qualified stock butterfly valve randomly selected method, or from a user-supplied but used a random sample method butterfly. The number of units and the minimum number of sampling units for each specification sampling valve according to regulations. When the user sampling, sampling for several unlimited number of sampling units based upon the requirements. When the entire family quality assessment, sampling department can be extracted from the series according to the situation two to three typical specifications butterfly test specifications for each sample based upon a predetermined minimum number of units and the number of sampling units.

2)Technical requirements and test methods for butterfly valve type test according to regulations. Each test subject butterfly valve housing, sealing test, leak tightness tests must meet all the technical requirements specified. The remaining types of test items, if they are seized with a butterfly valve in an index less than the prescribed technical requirements, it is allowed for the sample from the sampling valve in taking further the number of units required. When tested again, all the test items must comply with the technical requirements, or as unqualified goods.

Butterfly valves have the worm gearbox flange end hard seated single eccentric butterfly valve and worm gearbox flange end hard seated triple eccentric butterfly valve.

The worm gearbox flange end hard seated single eccentric butterfly valve represents the center of the butterfly valve,which is the valve stem axis, the center of the disc and the center of the body in the same position. Its advantages are simple structure, easy manufacturing, the disadvantage is due to the butterfly valve plate and seat is always in the squeeze, scratch state resistance from large, fast wear. Seat basically elastic material such as rubber and Teflon, so the temperature is limited only for low temperatures. The worm gearbox flange end hard seated single eccentric butterfly valve 150LB ~ 600LB ventilation valve in the metallurgical, chemical, building materials, power plants, glass and other industries in ventilation, dust cold or hot gas pipeline environmental projects, as the gaseous medium to regulate the flow or cutting device.

The triple offset butterfly valve, the valve stem axis refers to both departing from the center of the disc deviate from the center of the body, the shape of the cone Sealing is not a positive, but taper. The advantage is high temperature, good sealing performance. Triple eccentric butterfly valve 150LB ~300LB metal seal butterfly valve using sophisticated J-shaped elastic ring and three eccentric multi-level metal seal structure,which is widely used in medium temperature ≤425 ℃ of metallurgy, electric power, petrochemical, and water supply and drainage and municipal on construction and other industrial pipeline, for regulating the flow and the carrier off fluid use.

 

Should you want to know more about butterfly valve from Reliable China valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

15. August 2015 · Comments Off · Categories: Butterfly valves

At present, the butterfly valves as a piping system used to implement off and flow control components,which has been used in many fields of petroleum, chemical, metallurgy, water, electricity and very widely used. It has been known butterfly valve technology, the seal forms enclosed structure, sealing material for rubber, PTFE and so on. Since the structure of the restrictions, suitable for high temperature, high pressure and corrosion resistance, abrasion resistance and other industries.

Present a more sophisticated three eccentric butterfly valve is metal seal butterfly valve, butterfly valve and seat components for the piece, the butterfly valve seat sealing surface layer welding temperature, corrosion resistant alloy material. Multilayer soft stacked ring fixed in the butterfly valve plate, this butterfly valve in comparison with conventional high temperature, easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for seal, to improve a butterfly valve sealing performance and extended service life advantages, however, this butterfly valve is still in the course of the following problems:

1)The multi-Flex stacked ring fixed in the butterfly valve plate, when the butterfly valve plate normally open state media, the formation of a positive sealing surface erosion, and metal sandwich of soft seal by brushing with a direct impact on seal performance.

2)By the structural conditions of the restrictions of the structure do not meet the following path DN200 butterfly valve, because the overall structure of the butterfly valve plate thick, large flow resistance.

3)Because the principle of the three eccentric structure, sealing surface and the butterfly valve seat between the butterfly valve plate by the transmission of torque to seat the butterfly valve plate pressure. Positive flow state, the higher the pressure medium sealed tight squeeze. When the flow channel upstream medium with medium pressure valve plate and seat when positive pressure is less than medium pressure, the seal started to leak.

High performance triple offset  butterfly valve, characterized in that: the butterfly valve seat ring by a soft T-shaped sealing ring on both sides multilayer stainless steel sheet. The sealing surface of the butterfly valve plate and butterfly valve seat for the oblique cone structure, oblique cone surface in the butterfly valve plate welding temperature, corrosion resistant alloy materials; fixed regulation of the spring between the platen and the platen ring bolt assembly structure in regulation. This structure effectively compensate for tolerance between the sleeve and the butterfly valve stem and the elastic deformation under media pressure, the butterfly valve sealing problems in the course of transmission medium in the presence of two-way exchange. Use of soft T-type multi-layer stainless steel sheet ring on both sides, with the dual advantages of a metal seal and soft seal, both at low and high temperatures, all with zero leakage sealing performance.

Test proved positive flow state (medium flow direction and the disc rotation in the same direction), the sealing surface pressure is the transmission of torque and media pressure on the butterfly valve plate of the role of the elected. Positive medium pressure butterfly valve plate oblique cone surface and the butterfly valve seat sealing surface squeezed more tightly, sealing the better. When the counter-current state, the seal between the butterfly valve plate and seat the drive torque by means of the butterfly valve plate is pressed against the valve seat. When With the reverse media pressure, butterfly valve plate and seat the pressure between the less than medium pressure, adjustable ring of spring in compensation valve plate after deformation energy stored by the carrier seat sealing surface of the tight pressure play automatic compensation. Therefore, this utility model, unlike existing technologies, as install software and hardware multi-ring in the butterfly valve plate, but directly mounted on the butterfly valve body, the pressure plate and the middle seat an additional adjustment ring is a very good two-way sealed hard way . It can replace the plug valve and ball valve.

Should you want to know more about butterfly valve from Reliable China valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

15. August 2015 · Comments Off · Categories: Butterfly valves

Butterfly valve opening and closing member is a disc-shaped butterfly plate in the butterfly valve body around its own axis to achieve the opening and closing of the butterfly valve or regulator called butterfly. Butterfly valve fully open to fully closed is usually less than 90 degrees, butterfly and butterfly stroke itself is not self-locking powerful position for the disc to install the worm gear on the stem. Using worm reducer, not only can make the disc with self-locking capability, so the disc stop in any position, but also to improve the valve performance.

Butterfly valve installation and maintenance should note the following:
1)When installing the butterfly valve, the butterfly valve to be parked in the closed position.
2)The butterfly valve open position of the rotation angle of the disc should be OK.
3)With a butterfly valve bypass valve, the bypass valve opening should be preceded open.
4)The butterfly valve should be installed in accordance with installation instructions, heavy butterfly, set a solid foundation.

Should you want to learn more about butterfly valve, such as China triple offset butterfly valve, centerline butterfly valve from China valve manufacturer, please email via sales@reliavalve.com.

06. July 2015 · Comments Off · Categories: Butterfly valves

The difference between the triple eccentric butterfly valves and double eccentric butterfly valves.

First, the centerline butterfly valve (also called concentric butterfly valves).
Structural characteristics of centerline butterfly valve stem axis, the center of the disc, the central body in the same position. Simple structure, easy manufacture. rubber lined butterfly valve that is common in this category. The disadvantage is that due to the disc and seat is always in the squeeze, scratch state resistance from large, fast wear. To overcome the squeeze, scratch, to ensure the sealing performance, the seat is basically elastic material such as rubber or Teflon, but also because of the sealing material is restricted in the use of temperature, which is why traditionally people think butterfly valves cann’t be used in high temperatures.

Second, the single eccentric butterfly valves.
Structural features single eccentric butterfly valve stem axis deviated from the center of the disc so that the lower end of the rotation axis of the butterfly board is no longer a dispersed, reducing the excessive compression plate and the lower end of the butterfly valve to solve the concentric butterfly Squeeze the disc and seat. However, due to a single eccentric structure throughout the switching process in the valve disc and seat scratch phenomenon has not disappeared, the scope and concentric valve similar, so the use of small.

Third, the double eccentric butterfly valves.
Double eccentric butterfly valve further improved on the basis of a single eccentric butterfly on the application of the most extensive. The structure is characterized by both the stem axis deviated from the center of the disc, but also deviated from the center of the body. The effect of the valve double eccentric disc can later be turned quickly from the seat, largely eliminating unnecessary excessive compression disc and seat, scratching phenomenon, reducing the resistance from the open, reducing the wear and increased the seat life. Scratch greatly reduced, but also makes the double eccentric metal seated butterfly valve can also be used to improve the valve used in high temperature areas. But because of its location it belongs sealing principle sealing structure, namely the disc sealing surface and seat line contact, deformation of the sealing effect by pressing resilient seat butterfly plate caused, so the closed position demanding (especially metal seat), low bearing capacity, which is why people think  traditionally the high-pressure valve intolerance, large leakage reasons.

Four, triple eccentric butterfly valves.
When the butterfly valves are used in high temperature, we should use the hard sealing, but the leak volume; to meet zero leakage,we should use a flexible seal, but not suit for the high temperature. To overcome this contradiction for the double eccentric butterfly valves, and butterfly valves for the third time on the eccentric. The structure is characterized by the double eccentric eccentric stem axis position while the axis of the disc so that the conical sealing surface of the cylinder axis oblique to the body, that is, after the third eccentric butterfly plate sealing section is not then a true circle, but an ellipse, and therefore the sealing surface shape and asymmetry, while inclined to the centerline of the body, the other side is parallel to the centerline of the body.

This is the third most important feature is the eccentric fundamentally changed the seal structure, no longer is the location of the seal, but the torque seal, that instead of relying on the elastic deformation of the seat, but entirely on the seat of the contact surface pressure to achieve the seal effect, so one solution to the metal seat zero leakage of the problem, and because of the contact surface pressure and medium pressure is proportional to the resistance to high pressure and temperature are solved.

Posted by Relia Valve, Professional China valve manufacturer and China wafer valve supplier.