Straight-through stop valve J45H
I. Product Introduction:
Among straight-through or Y-type stop valves, the flow channel of the J45H straight-through stop valve forms an oblique line with the main flow channel, so the degree of flow state destruction is smaller than that of conventional stop valves, and the pressure loss through the valve is correspondingly reduced. Straight-through stop valves are particularly suitable for pipelines in the chemical and fertilizer industries; incorporating steam can prevent medium crystallization. They are widely used in various systems such as petroleum, chemical, metallurgical, and pharmaceutical industries to transport high-viscosity media that solidify at room temperature. Main Technical Parameters: Model Nominal Pressure (MPa) 1.6 J45H-16 Test Pressure (MPa) Shell 2.4 Seal 1.6 Working Temperature -30～180℃ Applicable Medium Water Main Part Materials: Model Stem, Bonnet Gray Cast Iron Gray Cast Copper J45H-16 Stem, Disc Carbon Steel Stem Nut Gland Packing Graphite Asbestos Gland Packing Main Dimensions (Flange dimensions shall comply with JB78 PN1.6MPa standards.)
II. Product Principle:
Stop valves belong to force-sealed valves, so when closing the valve, pressure must be applied to the disc to force the sealing surface not to leak. When the medium enters the valve from below the disc, the resistance that the operating force needs to overcome is the friction between the stem and the gland packing, and the thrust generated by the medium pressure. The force to close the valve is greater than the force to open the valve, so the diameter of the stem must be larger; otherwise, the stem may bend. In recent years, since the advent of self-sealing valves, the medium flow direction of stop valves has changed to enter the valve cavity from above the disc. At this time, under the action of medium pressure, the force to close the valve is small, while the force to open the valve is large, so the diameter of the stem can be reduced accordingly. Meanwhile, under the action of the medium, this type of valve is also more tightly sealed. China's valve "Three Standardizations for Supply" once stipulated that the flow direction of stop valves must be from top to bottom.
III. Product Features:
1. During the opening and closing process, the friction on the sealing surface is smaller than that of gate valves, making it wear-resistant.
2. The opening height is small.
3. Usually, there is only one sealing surface, with good manufacturing process and easy maintenance.
IV. Main Technical Parameters:
Model | Nominal Pressure (MPa) | 1.6 | |
J45H-16 | Test Pressure (MPa) | Shell | 2.4 |
Seal | 1.6 | ||
Working Temperature | -30～180℃ | ||
Applicable Medium | Water | ||
V. Main Part Materials:
Model | Stem, Bonnet | Gray Cast Iron | Gray Cast Copper |
J45H-16 | Stem, Disc | Carbon Steel | |
Stem Nut | Copper | ||
Gland Packing | Graphite Asbestos Gland Packing | ||
VI. Use and Maintenance:
The purpose of use and maintenance is to extend the service life of the valve and ensure reliable opening and closing. The stem thread frequently rubs against the stem nut, so a little dry grease, molybdenum disulfide, or graphite powder should be applied to play a lubricating role. Valves that are not opened and closed frequently should also rotate the handwheel regularly and add lubricant to the stem thread to prevent jamming. For outdoor valves, a protective sleeve should be added to the stem to prevent rust and contamination from rain, snow, and dust. If the valve is mechanically operated, lubricant should be added to the gearbox on time. The valve should always be kept clean. Regularly check and maintain the integrity of valve parts. If the fixing nut of the handwheel falls off, it must be replaced with a complete one; it cannot be used makeshift, otherwise the square part on the upper part of the stem will be worn round, gradually losing coordination reliability, and even making the valve unable to operate. Do not use the valve to support other heavy objects, and do not stand on the valve. The stem, especially the threaded part, should be wiped frequently. The lubricant contaminated by dust should be replaced with new one, because dust contains hard debris that easily wears the threads and stem surface, affecting the service life.
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