After a quality proper gate valve is selected, we should also guarantee that gate valve can be installed, maintained, and operated correctly, so that it can fully exert its effectiveness.
1. installation direction and position of gate valves:
Whether a gate valve is installed correctly directly affects the working of the gate valve, so we should pay more attention to make sure a gate valve is installed correctly.
Many valves are directional, such as globe valves, throttle valves, pressure reducing valve, check valve,etc. If they are installed upside down, it will affect the working and service life,(such as throttle valve), or they won’t work at all(such as pressure reducing valve), or even cause dangers(such as a check valve). generally, the gate valve has a direction mark on the valve body, if not, it should be correctly identified according to the working principle of the gate valve.
The installation location of the gate valve must be convenient for operation. Even if the installation place is temporarily inconvenient for operation, they should also consider the long time operation. The handwheel of the gate valve should be aligned with the chest of the human(usually 1.2meters away from the floor), so that it is easier to open and close the gate valve. The hand wheel of the landing gate valve should be upward, and do not tilt, so as to avoid awkward operation. For gate valve against wall or other machines, there should also be enough space for operating. It is not safe for the workers to look up to open and close the gate valve, especially for the acid and alkali, toxic mediums.
The gate valve should not be installed upside down(that is, the hand wheel is downward), otherwise the medium will remain in the bonnet space for a long time, which will easily corrode the valve stem, and which is prohibited by certain process requirements. It is extremely inconvenient to replace the packing at the same time.
The rising stem gate valve should not be installed underground, otherwise the exposed valve stem will be corroded due to moisture.
2. what should do during installation of gate valves:
The workers should be careful during the installation of gate valves, Don’t hit the gate valves made of brittle materials.
Before installation, check the specification and model no of the gate valve, identify whether there is some damage, especially for the valve stem. Then turn the stem a few turns to check whether it is skewed, because the stem is easily be hit during delivery. And also we should remove debris from the valve body.
When we are lifting the gate valve, do not tie the rope on the hand wheel or on the valve stem, to avoid damage to these parts, the rope should be tied to the flanges.
The pipeline connected to the gate valve must be cleaned. We can use compressed air to blow off iron oxide filings, mud sand, welding slag and other debris. These debris will not only easily scratch the sealing surface of the gate valve, but also large particles of debris(such as welding slag) can also block the small gate valve and make it invalid.
When installing the threaded gate valves, the sealing packing should be wrapped on the thread, do not get it into the gate valve, so as to avoid accumulation in the valve, and affect the flow of the medium.
When installing flange gate valves, pay attention to tightening the bolts symmetrically and evenly. The flanges of gate valve and the pipe flanges must be parallel, and reasonable space should be left out, so as to avoid cracking of the gate valve due to excessive pressure. Especially for those gate valve made of brittle material or material withe low strength.
For those gate valve who must be welded with the pipes, the connected part should be spot welded first, then open all the closing part, then welded them to fix.
3. protection of gate valve after installation.
Some gate valve must also have external protection after installation, which is heat preservation and cold preservation. Heat tracing steam lines are sometimes added in the insulation layer. What kind of gate valve should be kept warm or anti coldness, it depends on the real working requirements. In principle, if the medium in the gate valve lowers the temperature to much, which will affect the working efficiency or freeze the gate valve, then the gate valve need the heat preservation. When the gate valve is exposed, it is unfavorable for production or cause adverse phenomena such as frost, it needs to be kept warm. The insulation materials include asbestos, slag wool, glass wool, perlite, diatomite, vermiculite,etc; cold insulation materials include cork, perlite, foam, plastic,etc.
For the long time unused water and steam, the gate valve must release the accumulated water.
4. Bypass and Meter on the gate valve
For some gate valves, in addition to necessary protection facilities, there are also bypass and meters. A bypass is installed for the easy maintenance service of the steam trap. Other gate valves are also installed with bypass. Whether a gate valve should be installed with bypass, it depends on the condition of the gate valve, its importance and production requirements.
5. change of packing of gate valve.
For some gate valve at stock, some packings are not working well, and some are not working well the mediums, now we should replace the packing.
The gate valve manufacturers can not have full consideration about what kind of mediums those gate valves will be used for, so the gate valve is usually stuffed with ordinary packing, but if the customers have to consider what kind of packing material should be used according to different mediums.
When replacing the packing, press it in circle by circle. The seam angle of each circle should preferably 45 degree, and the circle seams are staggered by 180 degree. The packing height should consider the room for the gland to continue to be pressed, and let the lower part of the gland press the packing chamber to an appropriate depth, which can generally be 10-20% of the total depth of the packing chamber.
In addition to the above packing, according to real working conditions, the rubber O type ring can also be used( natural rubber resistant to weak alkalis below 60℃, Nitrile rubber resistant to oils below 80℃, fluoro rubber resistant to various corrosive mediums below 150℃), PTFE ring( resistant to strong corrosive mediums below 200℃), nylon ring( resistant to ammonia and alkali below 120℃）and other formed packing material. Wrapping a layer of PTFE raw material tape outside the ordinary packing, which can improve the sealing effect and reduce the electro-chemical corrosion of the valve stem.
if you want to know more information about the installation of industrial gate valves, or you have no idea what kind of material gate valve will be proper for your pipeline systems, kindly contact us: