In the water pump pipeline system, when suddenly stop the pump, the pump outlet check valve closed rapidly, resulting in a sudden drop of circulating velocity in the outlet pipe of the valve and produce back-flow impact pressure, the sudden change of speed will produce impact pressure wave transmission, transmission speed High, the valve outlet section pressure can be increased to several times the rated pressure, which is the phenomenon of water hammer in the pipeline, which can lead to valve or pipe rupture, resulting in accidents. In order to avoid such accidents, people nowadays adopt valves with delayed closing characteristics, such as two-stage controlled butterfly valve closing, a hydraulic control valve with a daughter valve plate, a slow closing check valve and the like, so that the valve is delayed off and part of the water passes through The pump and rotor components return to relieve water pressure to relieve pressure. However, due to the pressure relief time is longer, the backflow of water for a long time the impact of the pump impeller, pump rotor parts reverse speed, a long time will damage the pump rotor parts and associated rotor parts of the motor. 1 structure design As shown in Figure 1, the valve consists of a valve body, a hydraulic chamber, a hydraulic line and a hydraulic line b. The valve body is a four-way pipe with a hydraulic transmission rod, a lower valve plate, an upper valve plate, and threaded ends at both ends of the hydraulic transmission rod. The lower part of the valve body is connected with the bottom cover through a connecting screw. Each inlet and outlet of the upper and lower sides of the valve body is connected with a pipeline, a sealing seat is arranged in the middle of the valve body near the inlet and the outlet, the upper valve plate is connected with the hydraulic transmission rod by welding, The plate is connected with the hydraulic transmission rod through the nut, the thread at one end of the hydraulic transmission rod, and the upper part of the valve body is connected with the hydraulic cavity through the flange. The hydraulic chamber is composed of a hydraulic chamber seat, a hydraulic chamber cover, a hydraulic chamber and a piston, wherein the hydraulic chamber seat is provided with a hydraulic chamber seat sleeve through a screw rod, a nut and a valve body, the piston is in the hydraulic pressure chamber, Cavity seat cover with a nut, hydraulic drive rod at one end of the thread connected with the piston. The piston divides the hydraulic chamber into an upper chamber and a lower chamber. An O-shaped seal ring is provided on the piston, and the O-shaped seal ring on the piston is tightly sealed with the inner wall of the hydraulic chamber to completely separate the upper and lower chambers of the hydraulic chamber. The hydraulic chamber cover is provided with a through hole, and the hydraulic pipe a is communicated with the upper chamber of the hydraulic chamber through the through hole. The hydraulic chamber seat is provided with a through hole, and the hydraulic tube b communicated with the lower chamber of the hydraulic chamber is communicated with the lower chamber of the hydraulic chamber through the through hole. Install "O" ring seal on the upper valve plate, lower valve plate and hydraulic chamber seat sleeve, install gaskets on the mating surface between the hydraulic chamber cover and the hydraulic chamber, Install the gasket on the interface between the valve seat and the valve body, install the gasket on the interface between the valve seat and the valve body, and install the gasket between the valve body and the bottom cover and on the interface between the valve seat and the valve body. A filter installed in the hydraulic pipe, micro-valve control valve, the hydraulic pipe b to install the filter, regulating valve. The hydraulic chamber cover is provided with a through hole through the through hole and then connected to the hydraulic pipe c, which is equipped with micro check valve above the hydraulic chamber cover installed deflation screw plug. Install a bleed plug on the hydraulic chamber cover that can be used to vent the gas in the upper chamber of the hydraulic chamber. The hydraulic chamber in FIG. 2 is composed of a hydraulic chamber seat, a hydraulic chamber cover, a hydraulic chamber and a diaphragm plate, a diaphragm and a diaphragm gland. The upper plate, the diaphragm and the diaphragm of the diaphragm are gland- Diaphragm on the diaphragm above the diaphragm gland under the diaphragm, the hydraulic transmission rod seat through the hydraulic chamber sleeve, with nuts, hydraulic transmission rod at one end of the thread and diaphragm gland, diaphragm, diaphragm plate Into one, the hydraulic chamber cover, the diaphragm and the cavity between the cavity by screw, nut connection, the diaphragm will be divided into two chambers up and down the hydraulic chamber, and the upper and lower chamber completely isolated. 2 working principle and function The bypass pilot relief valve with the above structure is used for conveying the fluid piping system and is installed on the bypass relief pipe at the outlet side of the check valve on the pump outlet to achieve the following functions and effects (see Figure 3) . When the pump is in starting state, the pressure in the lower chamber of the hydraulic chamber connected with the hydraulic pipe is higher than the pressure in the upper chamber of the hydraulic chamber connected with the hydraulic pipe. Under the action of the pressure difference, the piston moves upward and drives the lower valve plate through the hydraulic transmission rod Move up, this time, the next into the liquid outlet into the outlet, and through the valve body out from the outlet. When the piston moves upward and drives the lower valve plate to move upwards through the hydraulic transmission rod until the lower valve plate touches the sealing seat in the valve body, the O-shaped sealing ring 5 on the lower valve plate is compressed and sealed, The upper and lower outlet and the lower inlet and outlet without liquid flow, this time, the pump and piping system is in normal working condition, the hydraulic chamber cover connected to the hydraulic pipe can speed up the hydraulic fluid flow velocity, so that the process quickly. When a sudden power outage, the check valve automatically shut down, then the pressure on the cavity of the hydraulic chamber is greater than the pressure in the lower chamber of the hydraulic chamber, the piston moves downward under the pressure difference and drives the lower plate to move downward. The "O" The sealing ring loses the sealing effect, and the liquid in the upper and lower outlet flows into the valve and is discharged from the lower inlet and outlet through the valve body. At the same time, the upper valve plate moves downwards synchronously with the sealing seat in the valve body under the driving of the hydraulic transmission rod, O "ring seal is compressed from the sealing effect, this time on the inlet and outlet to stop the flow of liquid, the elimination of hydraulic effects. From the lower valve plate and the upper valve plate at the same time moving down, "O" ring seal to seal the beginning of the "O" ring seal from sealing this time is the pressure relief time. The gaskets are used to ensure that the liquid in the hydraulic chamber is not leaked. The gaskets are used to ensure the liquid in the valve body is not leaked. The O-ring seal on the hydraulic chamber housing isolates the fluid in the hydraulic chamber from the valve body. In order to adjust the pressure relief time, a hydraulic control valve is installed on the hydraulic pipe. The pressure relief time can be controlled by the regulating valve to regulate the inflow and outflow of liquid in the upper and lower cavities in the hydraulic chamber. Equipped with a filter in the hydraulic pipe to filter impurities in the liquid to ensure that the hydraulic chamber clean. A micro-check valve is mounted on the hydraulic line and can be used to throttle the flow of water into the upper chamber of the hydraulic chamber. The flexible valve action, adjustable closing time (the fastest 15s, the slowest 348s), for complex pipe network system, eliminating the effect of water hammer, and completely solve the two-phase shut-off valve slow off a long time, Turn the problem. 3 application Has designed and manufactured three types of pressure relief valves of 80mm, 150mm and 300mm in diameter with a nominal pressure of 1.6MPa. It has been applied to tap water, metallurgical cooling circulating water and petrochemical cooling circulating water piping systems. After nearly one year of operation, Off time adjustable, for complex pipe network system, eliminating the effect of water hammer, and completely solve the two-phase shut-off valve slow off a long time, backwater impact reversal problem. Description of valve structure and performance of the design method is feasible, accurate parameter selection. Bypass hydraulic control relief valve installed in the main pipeline check valve outlet side of the bypass pipe, with the check valve used in conjunction with the use of pressurized liquid in the pipeline to achieve the drive and automatic control, completely solve the traditional two-stage shutdown Valve to eliminate water hammer pressure when the pump rotor rotor parts to reverse the problem. Due to its adjustable closing time, it is applicable to a variety of complex pipelines to eliminate water hammer pressure. It is a new type of pressure relief valve with extended application value.
Fine bubble plate diffuser for sewage treatment is structured in the unique manner that makes the aeration system maintain constant oxygenation transfer efficiency within the wide range of working air.The diffuser`s support board is made of aluminum alloy with a layor of membrane horizontally laid on the board.The membrane,once formed,will not suffer debonding .The diffuser can be applied to either intermittent or continuous operation system.Therefore, Holly series plate-type diffuser is the preferred choice for large-scaled and medium-scaled sewage treatment plants.
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In order to solve the above problems, it is necessary to design an automatic pressure relief valve installed in the bypass pipe, which can lead the backflow to the inlet of the pump during the pressure relief time, that is, the pressure relief backflow no longer passes through the pump rotor part to complete the pressure relief Can be automatically shut down, completely solve the pressure relief back to the impact of the pump reversal problem, and to effectively eliminate the purpose of water hammer.
Fine Bubble Plate Diffuser
