PP Globe Valve Installation method PVDF Globe Valve standards PPH Globe Valve Selection principle

The installation and maintenance of PP Globe Valve globe valve should pay attention to the following items:
1, handwheel, handle operated globe valve can be installed in any position of the pipeline.
2. Handwheel, handle and micro mechanism are not allowed to be used for lifting.
3, the flow direction of the medium should be consistent with the direction of the arrow shown in the valve body.

Globe valve main standards: 1, GB/T 12233-2006 "Universal valve iron globe valve and lifting check valve"
2, GB/T 12235-2007 "General purpose flanged steel globe valve and lift check valve"
3, JB/T53174-94 "Stop valve product quality grading"
4, JB/T53165-92 "high pressure balance stop valve"
5. GB/T 587-2008 Marine Flange Bronze globe valve
6, GB/T 590-2008 "Marine flange cast iron globe valve"
7, GB/T 8644-2008 "Iron and copper thread connection valves"
8, GB8465.2-87 "Internal thread connection gate valve, globe valve, ball valve, check valve basic size of iron globe valve"

Globe valve refers to the closing piece (disc) along the center line of the valve seat movement. According to the moving form of the disc, the change of the valve seat opening is directly proportional to the disc stroke. Due to this kind of valve stem open or close stroke is relatively short, and has a very reliable cut off function, and because of the change of the valve seat opening and the stroke of the disc is directly proportional, very suitable for flow regulation. This type of valve is therefore ideal for use as a cut-off or regulator and throttling.
PVDF Globe Valve Selection principle: 1, high temperature, high pressure medium pipeline or device should choose stop valve. Such as thermal power plants, nuclear power plants, petrochemical systems of high temperature, high pressure pipeline.
2, the pipeline convection resistance requirements are not strict pipeline. Where the pressure loss is not taken into account.
3, small valves can choose needle valve, instrument valve, sampling valve, pressure gauge valve, etc.
4, there is flow adjustment or pressure adjustment, but the adjustment accuracy is not high, and the diameter of the pipeline is relatively small, such as the nominal passage ≤50mm pipeline, should be selected.
5, the synthetic industrial production of small chemical fertilizer and large chemical fertilizer should choose the nominal pressure PN160 nominal pressure 16MPa or PN320 nominal pressure 32MPa high pressure Angle globe valve or high pressure Angle throttle valve.
6, alumina Bayer method in the production of desilication workshop, easy to coking pipeline, easy to choose separate valve body type, seat can be removed, carbide sealing pair of straight flow globe valve or straight flow throttle valve.
7. In the water supply and heat supply engineering of urban construction, cut-off, balance valve or plunger valve can be used for smaller pipelines with nominal passage, such as pipelines with nominal passage less than 150mm.

PPH Globe Valve Advantages: In the process of opening and closing, the friction between the valve disc and the sealing surface of the valve body is smaller than the gate valve, so the wear resistance. The opening height is generally only 1/4 of the diameter of the valve seat channel, so much smaller than the gate valve. Usually there is only one sealing surface on the valve body and disc, so the manufacturing process is better and easy to maintain.
Nominal pressure or pressure level: PN1.0-16.0mpa, ANSI CLASS 150-900, JIS10-20K Nominal diameter or caliber: DN10 ~ 500, NPS 1/2 ~ 36" Connection mode: flange, butt welding, thread, etc. Applicable temperature: -196℃ ~ 700℃ Driving mode: , pneumatic, electric, hydraulic, gas-liquid linkage, valve body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8(304), CF3(304L), CF8M(316), CF3M(316L), Ti. Choose different materials, can be respectively suitable for water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.

Operation: For globe valves, not only must be able to install and maintain, but also to operate.
Open and close the globe valve, the force should be smooth, not impact. The impact force of some high-pressure globe valve components has been considered and the general globe valve can not be equal. When the stop valve is fully open, the handwheel should be reversed a little, so that the thread between tight, so as not to loose damage. When the pipeline is used for the first time, there are more internal dirt, so the stop valve can be micro-opened, washed away by the high-speed flow of the medium, and then gently closed (not fast closed, fierce closed, to prevent residual impurities from clamping the sealing surface), opened again, repeated many times, wash the dirt, and then put into normal work.Normally open globe valve, there may be dirt on the sealing surface, when closed, it should also be washed clean with the above method, and then formally closed. If the handwheel and handle are damaged or lost, they should be completed immediately, and can not be replaced by movable plate hands, so as not to damage the stem quartet, opening and closing is not effective, resulting in accidents in production.
Some media, cooling after the cut-off valve is closed, so that the valve parts shrink, the operator should be closed again at the appropriate time, so that the sealing surface does not leave a fine seam, otherwise, the medium from the fine seam high-speed flow, it is easy to wash the sealing surface.
During operation, if it is found that the operation is too laborious, the cause should be analyzed. If the packing is too tight, it can be properly relaxed, such as the valve stem skew, should inform the personnel to repair. Some globe valves, in the closed state, the closed parts are heated expansion, resulting in difficult opening; If it must be opened at this time, the cover can be unscrewed half a circle to a circle to eliminate stem stress, and then the plate to start the wheel.

The sealing surface of the globe valve must be forced to close the valve to achieve sealing. Under the same caliber, working pressure and the same driving device, the driving torque of the globe valve is 2.5~3.5 times that of the gate valve. This should be noted when adjusting the torque control mechanism of the electric valve.
The sealing face of the globe valve only contacts each other when it is completely closed. The relative slip of the forced closing spool and the sealing face is very small, so the wear of the sealing face is also very small. And the sealing surface of the globe valve wear, most of it is due to the spool and sealing surface before there are sundries, or due to the closed state is not strict, causing high-speed scouring of the medium.
When the globe valve is installed, the medium can be entered from the bottom of the spool and from the top into two ways. The advantage of medium entering from the lower part of the spool is that when the valve is closed, the coil is not under pressure, which can prolong the service life of the coil, and can be replaced in the case of pressure in the pipe before the valve. Medium from below the valve into the disadvantage is that the valve driving torque is larger, about 1.05~1.08 times of the upper into the stem by the axial force, the stem is easy to bend. To this end, the medium from below into the way, generally only suitable for small manual stop valve, the valve is closed when the medium on the spool force is not greater than 350kg. Electric globe valve is generally adopted from the top of the medium into the way. The disadvantage of the medium coming in from above is the opposite of the medium coming in from below.