[Abstract] Power plants provide sufficient power support for our country's economic construction and people's life and study, making people's lives more convenient and faster. However, the construction and operation of power plants are not easy, and there are always various kinds of leakage. This affects the normal operation of power plants and, in severe cases, may endanger personal safety. Therefore, we must do a good job of handling the leakage of power plants. Ensure people's life and health and normal production and life.
[Key words] power plant; leakage outside the valve; pressure plugging "safety production" is a problem that we have been emphasizing all along. Only when the safety issue is guaranteed, all activities become meaningful. Power plant valve leakage is a serious security issue, and only deal with this issue in order to better start the power plant production and construction work.
1 valve leakage hazards Power plant valves for a variety of equipment, each pipeline fluid medium flow plays a controlling role. Valve leakage occurred in the packing, flange seals and valve body, and a long time leakage will erosion stem and flange sealing surface, and ultimately make the valve strike. The loss of fluid medium among them aggravates the consumption of power plants and increases the cost of power plants, resulting in a decrease in economic benefits. What is more serious is that if the external leakage is poisonous, harmful, inflammable, explosive and corrosive medium fluid may lead to the occurrence of poisoning, fire and other casualties, even the corrosion of plant equipment and the short service life, Destroy the surrounding ecological environment, endanger the health and safety of people's lives. Therefore, the leakage of the valve in the power plant is a serious safety issue and should be highly valued by the power plant. Only properly handled power plants can ensure the normal operation of the plant and avoid damage.
2 The main performance of the valve leakage and its causes 2.1 Leakage of valve packing In the working state of the valve, the valve stem and packing between the presence of rotation and axial movement of the relative movement. With the passage of time, the number of valve opening and closing gradually increased, the relative movement of the number will increase, coupled with temperature, pressure, fluid and other effects of the media, the valve packing leakage occurs. The elasticity of the packing is also diminished even under the dual influence of its aging and the contact pressure, even losing its elasticity. At this time, it gives an outward leakage of the pressure medium. Over time, it is possible to make part of the packing And the valve stem is flushed out of the groove, the situation of leakage is aggravated.
2.2 The leakage of the valve flange Preload of the connecting screw is the main rely on the valve flange seal, with the help of gaskets can achieve adequate seal than the pressure, so as to ensure that the sealed fluid pressure medium does not leak. Valve flange leak is due to many reasons, when the gasket pressure is not enough, the joint surface is not rough enough, whether it is mechanical vibration, or gasket deformation will make the gasket and the flange between the tight fit , Eventually a leak. In addition, the bolt deformation, gasket aging, deterioration of elasticity, cracking and so will make the flange surface of the seal is not tight, the event of leakage. Human factors are also an important factor in flange leaks. For example, in the process of gasketing devices, the partial sealing ratio does not meet the requirements and exceeds the limit of its design, so that the force is no longer required, which is also prone to occur Leakage accident.
2.3 The leakage of the valve body The leakage occurred mostly because of the valve production failed in the valve casting, forging phase did not handle well, resulting in valve defects, such as cracks, trachoma, can not guarantee that the valve body is in Best working condition Cavitation, the erosion of the fluid medium is also one of the causes of leakage outside the valve body.
3 common methods of pressure plugging 3.1 valve packing leakage For now, the injection pressure plugging technology is a more secure and reliable technical means, which requires the use of its unique fixture, hydraulic injection tools, the fixture And leakage part of the outer surface of the formation of the seal cavity injection sealant, quickly and effectively make up for a variety of leak defects. When the injection pressure is greater than the pressure of the leakage medium, the leakage was stopped by a strong impact, in a short period of time from the plastic injection into a flexible body, a flexible sealing structure formed in this way, And to maintain an effective working pressure, to achieve the valve seal again. According to the thickness of the valve wall letter has a different method of sealing:
3.1.1 injection treatment when the valve packing box wall thickness of 8mm above, the method can be used to directly open the injection hole, the valve packing letter that is sealed chamber, when the seal is injected into the valve when the stuffing box is filled It plays the same role as the filler. First, the size of the injection plastic head as a reference, drilled a suitable depth of the blind hole, and then tap the tapping operation, and then into the plastic injection joints, with the help of long drill through the plastic injection head, open the filler wall, Eventually into the stuffing room. In the operation of the process should pay attention to personal safety, especially when the drill is opened, prone to drilling after the gas, liquid, etc. along the thread penetration jet hurt out of the operator. In this regard, the operator should stand on the side of the drill pipe, or step-down preparatory work, so you can avoid injury accidents. You can also use baffles to drill holes through baffles, so that the risk factor is greatly reduced.
3.1.2 Auxiliary fixture treatment When the wall thickness is thin, need to use a specific auxiliary fixture to make up for the lack of valve packing box wall thickness, acting as a special connector, connected to the high-pressure injection gun and valve stuffing box. However, the formation of the ideal local bonding surface is somewhat difficult. Under certain conditions, the outer wall of the valve stuffing box can be properly repaired so as to be better fitted with the auxiliary jig. If the actual situation does not allow the repair, we can use asbestos rubber plate or ordinary rubber pad at the bottom of the auxiliary fixture, and then screw the fixture bolts, so that the fit of the gap can be better blocked. In addition, the auxiliary fixture should be
equipped with a screw
plug fitted with the injection
plug valve , the next step in the operation, when the sealing operation is completed, the valve can not be implemented on the switch immediately, only the sealed injection curing agent to normal start use.
3.1.3 Foreign body injection method The sealant with the help of the caulking effect is not perfect, there may be leakage, so we have to re-sealant, add some "foreign body" to plugging purpose. "Foreign body" mentioned here generally refers to the items made of soft metal lead and brass, the diameter is generally not more than 3mm.
3.2 Valve Flange Leak 3.2.1 Copper Sealing Law When the gap between the flange is small, the flange diameter is small, the medium pressure can be used to force small hours of copper sealing flange sealing method. It should be noted in the operation is not required to loosen the nut at the same time, making the gasket pressure significantly lower than the pressure, increase the amount of leakage, more serious may be the case of leakage media blowing away the gasket, which will result Irreparable consequences. Leakage at the beginning of a larger time with a special fixture to balance the pressure seal. If the flange gap pressure is inconsistent, the wide part of the gap in the selection of copper wire, hammer in hand with the help of partial play copper wire, and narrow gap to adapt.
3.2.2 injection fixture sealing method This method is applied to the flange clearance of not less than 10mm, flange screw pressure of not less than 2.06MPa, flange screw diameter of not less than 32mm, multiple bolt flange seal. Fixture or two or four flap, by the appropriate number of bolts. The fixture has a plastic injection connector. Can be used with flange bolts sealant injection work. In operation should be noted that: the width of the fixture and the flange should be adapted to the gap between the fixture and the flange can better fit together, the gap should be moderately tight to ensure that the injection of the agent will not leak plastic.
3.3 Valve Body Leakage 3.3.1 Adhesive Method Adhesive tape pressure sealing, adhesive has a curing speed characteristics, so the pressure medium, the amount of leakage are small trachoma can be directly taken to block the method leak. In the medium pressure is high, the amount of leakage, the use of pressure tools can be used for sealing operations, the actual operation to be fixed pressure tools. So that the screw is on the leak point, the use of its top rivet squeeze the leak site, to stop the purpose of leakage. When the area of ​​the top of the rivet is smaller than the leakage point, soft metal can be used to make up for the difference, stop the leakage and timely clean up the residue around the leakage point and wipe the adhesive. With adhesive curing can remove the relevant tools, at this time can also be used without the relevant glass reinforcement.
3.3.2 Welding method In the body of the medium high pressure, leakage can be used when the method of drainage welding. In the iron with the help of the leakage of media diversion. When the fitting surface is not good, rubber, asbestos pad, welded iron plate and valve body can be placed on the bonding surface, and the effect of sealing again after closing the isolation valve. Low medium pressure, small amount of leakage, you can use the diameter greater than double the leak plus nut. Guide the leakage medium, and the nut welded to the valve body, with the same specifications and around the top of the screw tape, with the help of asbestos mat, rubber pad, tighten the bolt can achieve the purpose of leakage.
In summary, the pressure plugging is a new type of technology, under certain conditions can effectively achieve plugging, this is not perfect, still need to continue to improve, supplemented by other plugging measures In order to truly plug the power plant work to achieve safety in production.
[Editor: Wang Weiping]
Potassium Humate
Potassium humate is an efficient organic potash fertilizer, Humic Acid is a biologically active agent that can increase the content of available potassium in soil, reduce the loss and fixation of potassium, increase the absorption and utilization of potassium.It also have functions of improving soil, promoting crop growth, improving resistance & quality of crops, protecting agricultural ecological environment and other functions. It can be mixed into a highly efficient multi-functional compound fertilizer with urea, Phosphate Fertilizer, potash fertilizer, trace elements, etc.
Powder
|
Water-solubility(dry basis)
|
80% Min
|
95% Min
|
75% Min
|
95% Min
|
95% Min
|
|
Content of Humic Acid(dry basis)
|
45-55%
|
55% Min
|
60% Min
|
65% Min
|
68% Min
|
|
Moisture
|
15% Max
|
15% Max
|
15% Max
|
15% Max
|
15% Max
|
|
K2O (dry basis)
|
7% Min
|
8% or 10% Min
|
10% Min
|
8% or 10% Min
|
10% Min
|
|
PH Value
|
9-10
|
9-10
|
9-10
|
9-10
|
9-10
|
Granular
|
Water-solubility(dry basis)
|
80% Min
|
75% Min
|
95% Min
|
|
Content of Humic Acid(dry basis)
|
45-55%
|
60% Min
|
68% Min
|
|
Moisture
|
15% Max
|
15% Max
|
15% Max
|
|
K2O (dry basis)
|
8% Min
|
10% Min
|
10% Min
|
|
PH Value
|
9-10
|
9-10
|
9-10
|
Flakes
|
Water-solubility(dry basis)
|
95% Min
|
95% Min
|
|
Content of Humic Acid(dry basis)
|
55% Min
|
65% Min
|
|
Moisture
|
15% Max
|
15% Max
|
|
K2O (dry basis)
|
8% Min or 10% Min
|
8% Min or 10% Min
|
|
PH Value
|
9-10
|
9-10
|
|
Size
|
40mesh, 60mesh, 2-4mm
|
1.Potassium humate can be used as base fertilizer, top dressing, seed fertilizer, foliar fertilizer, and spray fertilizer.
Basal fertilizer: 400-600kg/ha, has better effective applying with N P fertilizers
Top dressing: 300-400kg/ha, has better effective applying with N P fertilizers, and irrigate in time.
2.Combined with nitrogen and phosphorus to be used as multi-functional compound fertilizer,
Benefits
For Plant:
1.Plant growth stimulant, promote root development and stimulates seed germination.
2.Enhance nutrient uptake by combining nutrients and humic acids and keep a well-balanced nutrition.
3.Enhance the resilience of crops. such as cold, drought, pest, disease and toppling resistance.
4.Promotes healthier, stronger plants and enhance appearance
5.Potassium is an important component of chlorophyll, speed up the photosynthesis.
For Soil:
1.Soil conditioner. Improve soil structure. Increase ion exchange capacity of soil.
2.Enhance resistance to stress for soil, especially reduce high salts in alkaline soils.
3.Enhance nutrients uptake and increases the content of humus in soil.
4.Prevents soil from contamination of heavy metallic ions as well as other harmful matters.
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