Use and maintenance of Ball Valve

The purpose of use and maintenance is to extend the life of the Ball Valve and ensure reliable opening and closing. The valve stem thread often rubs against the valve stem nut, and needs to be coated with yellow dry oil, molybdenum disulfide or graphite powder for lubrication. For Ball Valve that are not frequently opened and closed, the handwheel should also be turned regularly to add lubricant to the valve stem thread to prevent biting. For outdoor Ball Valve, a protective cover should be added to the valve stem to prevent rain, snow, dust and rust. If the Ball Valve is mechanically ready, the gearbox should be lubricated on time. The integrity of the Ball Valve components should always be maintained. If the fixing nut of the handwheel falls off, it should be matched and cannot be used as a makeshift, otherwise the square of the upper part of the valve stem will be rounded, and the matching reliability will gradually be lost, and it may even be unable to start. The valve stem, especially the threaded part, should be wiped frequently, and the lubricant that has been contaminated by dust should be replaced with a new one, because the dust contains shadow impurities, which can easily wear the thread and the surface of the valve stem, affecting the service life of the Ball Valve. The Ball Valve in operation should be maintained once every quarter, once every six months after commissioning, once a year after two years of commissioning, and before winter every year. The Ball Valve flexibility operation and sewage discharge should be performed once a month.

15 October-2024

Storage and maintenance of Throttle Valve

The purpose of storage and maintenance is to prevent the Throttle Valve from being damaged or reducing its quality during storage. In fact, improper storage is one of the important reasons for the damage of Throttle Valve. The storage of Throttle Valve should be well organized. Small Throttle Valve should be placed on the shelves, and large Throttle Valve can be neatly placed on the floor of the warehouse. They should not be piled up randomly, and the flange connection surface should not be directly in contact with the ground. This is not only for aesthetics, but more importantly, to protect the Throttle Valve from being damaged. Due to improper storage or handling, the hand wheel is broken, the valve stem is crooked, and the fixing nut of the hand wheel and the valve stem is loosened and lost. These unnecessary losses should be avoided. For Throttle Valve that are not used in the short term, the asbestos packing should be removed to avoid electrochemical corrosion and damage to the valve stem. The inlet and outlet of the Throttle Valve should be sealed with wax paper or plastic sheets to prevent dirt from entering and affecting the Throttle Valve. For Throttle Valve that can rust in the atmosphere, anti-rust oil should be applied to protect them and prevent rust. Throttle Valve placed outdoors must be covered with rainproof and dustproof items such as tarpaulin or tarpaulin. The warehouse where the Throttle Valve are stored must be kept clean and dry.

14 October-2024

Precautions for selecting and replacing Throttle Valve

The selection of Universal Valve structure is determined by comprehensive consideration of factors such as the medium used, temperature, pressure before and after the valve, flow rate, physical and chemical properties of the medium, and the cleanliness of the medium. The correctness and rationality of the Throttle Valve structure selection are directly related to the performance, adjustment performance, adjustment stability, and service life. 1. Process parameters ① Medium name. ② Medium density, viscosity, temperature, medium cleanliness (with particles). ③ Medium physical and chemical properties: such as corrosiveness, toxicity, acidity and alkalinity. ④ Medium flow: maximum, normal, minimum. ⑤ Medium pressure before and after the valve: maximum, normal, minimum. ⑥ Medium viscosity, the greater the viscosity, the more it affects the calculation of Cv value. These parameters are mainly used to calculate the required caliber, rated Cv value and other dimensional parameters of the Throttle Valve, as well as the appropriate materials that the Throttle Valve should adopt. 2. Functional parameters ① Action mode: electric, pneumatic, electro-hydraulic, hydraulic. ② Throttle Valve function: adjustment, cut-off, adjustment and cut-off common. ③Control mode: positioner, solenoid valve, pressure reducing valve. ④Action time requirements. These parameters are mainly used to determine some accessories required to meet the functional requirements of the Throttle Valve. 3. Explosion-proof protection parameters ① Explosion-proof level. ② Protection level. 4. Environmental and power parameters ① Ambient temperature. ② Power parameters: air source pressure, power supply pressure. If the Throttle Valve is replaced, the following size parameters should also be provided to avoid the Throttle Valve being unable to be installed, or not being installed, or insufficient space due to inconsistency of Throttle Valve manufacturers, different standards adopted, or different Throttle Valve structures.

12 October-2024

Installation requirements for Throttle Valve

(1) For boilers with a rated evaporation capacity greater than 0.5t/h, at least two Throttle Valve shall be installed; for boilers with a rated evaporation capacity less than or equal to 0.5t/h, at least one Universal Valve shall be installed. Throttle Valve must be installed at the outlet of the split economizer and the outlet of the steam superheater. (2) Throttle Valve shall be installed vertically at the highest position of the boiler drum or header. No outlet pipe or valve for taking steam shall be installed between the Universal Valve and the drum or header. (3) Throttle Valve shall have a device to prevent the weight from moving on its own and a guide to limit the lever from going off the track. Spring-type Universal Valve shall have a lifting handle and a device to prevent the adjustment screw from being turned at will. (4) For boilers with a rated steam pressure less than or equal to 3.82MPa, the throat diameter of the Throttle Valve shall not be less than 25mm; for boilers with a rated steam pressure greater than 3.82MPa, the throat diameter of the Universal Valve shall not be less than 20mm. (5) The cross-sectional area of ​​the connecting pipe between the Throttle Valve and the boiler shall not be less than the inlet cross-sectional area of ​​the Universal Valve. If several Universal Valve are installed together on a short pipe directly connected to the boiler drum, the passage cross-sectional area of ​​the short pipe should not be less than 1.25 times the exhaust area of ​​all Universal Valve. (6) The Throttle Valve should generally be equipped with an exhaust pipe, which should be directly connected to a safe place and have a sufficient cross-sectional area to ensure smooth exhaust. The bottom of the exhaust pipe of the Universal Valve should be equipped with a drain pipe connected to a safe place. Valves are not allowed to be installed on the exhaust pipe and the drain pipe.

10 October-2024

Working principle of Throttle Valve

Under normal working conditions, the Throttle Valve is in the closed state, and the lower disc of the pilot valve is in the open state. The pipeline medium enters the air chamber above the Universal Valve through the lower disc, closing the Universal Valve. When the pipeline medium pressure is abnormal and reaches or exceeds the set setting force, the lower disc of the pilot valve closes under the action of the medium pressure, cutting off the passage of the pipeline medium entering the upper part of the Universal Valve. At the same time, the Throttle Valve is lifted by the push rod, that is, the pilot valve opens, and the medium in the air chamber above the Universal Valve is quickly discharged through the exhaust joint. Under the strong action of the lower medium pressure, the Universal Valve opens instantly, and the pipeline medium is quickly and massively discharged from the outlet of the main valve, so that the pipeline medium pressure returns to the normal working pressure, ensuring the safety of the system. When the pipeline pressure drops to about 90% of the set pressure set by the system, the Throttle Valve closes under the action of the spring, and at the same time, the lower disc of the pilot valve is pushed open by the push rod, and the pipeline medium enters the air chamber above the Universal Valve through the lower disc. The Universal Valve closes under the action of the pressure difference, ensuring the normal operation of the system. When the pipeline medium pressure is found to be abnormal and the pilot valve fails to open, the relief valve on the pilot valve can be manually opened to release the medium in the air chamber above the Universal Valve, so that the Universal Valve can be opened to release the abnormal medium pressure in the pipeline and ensure the safety of the system.

09 October-2024