A ball check valve is a check valve in which the closing member, the movable part to block the flow, is a spherical ball. In some ball check Valves, the ball is spring-loaded to help keep it shut. For those designs without a spring, reverse flow is required to move the ball toward the seat and create a seal. The interior surface of the main seats of ball check valves are more or less conically-tapered to guide the ball into the seat and form a positive seal when stopping reverse flow. Check Valves, Water Check Valves, Brass Check Valves, Sanitary Check Valves ZHEJIANG KINGSIR VALVE CO., LTD. , https://www.kingsirvalve.com
Regardless of the type of pump, it is important to understand the condition of the equipment before overhauling it. It is important to know which parts are likely to be damaged, to be replaced during overhauls, and to have spare parts prepared in advance. Before stopping the pump, conduct a detailed inspection of the equipment. After the maintenance work procedures. Before the pump is overhauled, it is necessary to check whether the safety measures are complete and whether the pressure inside the pump is on the net. Centrifugal pump overhaul in order, that is, demolition, inspection, assembly three big not. Due to the different pump structure, the specific program content is not the same. For 48Sh-22 pump, the working steps are as follows:
A .. Sh-type centrifugal pump overall removal (1) separate the pump housing demolition coupling pin, the pump and the motor from. Remove the horizontal joint bolts and pins to separate the pump cover from the lower pump body. And remove the packing gland. Decompose piping with connections to the system (eg air pipes, sealed water pipes). Decomposition pipe head with cloth, to prevent falling into debris.
(2) Hanging pump cover After the above work 1 is completed and checked, the pump cover can be lifted. Be steady when lifting, be careful not to get stuck with his parts.
(3) hanging rotor to the ends of the bearings apart, remove the bearing and the bearing. Pull the oil ring to the two sides of the bottom bearing, which is not to be taken out of the bottom bearing under lifting. Wire rope wear at both ends of the rotor (packing gland at) lifting, to level safe.
Two.Sh centrifugal pump inspection cleaning (1) pump body bearing inspection. See if there is wear and tear, burns; Wujin is born (the old bearing as long as the hand by a click of black gold, the oil will be squeezed out from the brim of the seam). If you can not continue to use to be new. New bearing also have to check the case of bodiless, soak in kerosene check. Born area not more than 20%. Bearing body to be cleaned, and check the oil window is transparent. Pump cooling water, sealed water channel is blocked, with or without leakage, should be kept open and in good condition. Pump cover and pump body clean surface. No combination of surface, asbestos mat to be complete, if damaged, according to the original thickness of the replacement.
(2) Check the rotor part of the impeller wear, cavitation, and check for cracks. If you can continue to use it without having to remove from the shaft, because it is generally difficult to disassemble. If you need to remove the non-must use special tools to disassemble and remove the heating.
After removing the impeller, the shaft should be clean, side axle curvature of the bay. Bush often friction with the filler, especially when the sand with water is particularly serious, so the general situation should be replaced.
Make a protective ring inlaid on the water wheel (usually a large pump impeller inlaid with a protective ring, so the re-allocation of the old should be removed). Impeller and seal ring with the gap selected by the table.
Check single row radial ball bearings 20 is qualified, check the following methods:
â‘ rolling body and raceway surface can not have spots, holes, dents, peeling, peeling phenomenon.
â‘¡ rotating flexible, hand rotation should be smooth, and gradually slow down and stop, can not suddenly stop, can not have vibration.
â‘¢ isolated frame and the inner and outer rings should be the same gap can be used to promote the radial isolation rack test.
â‘£ clearance appropriate, with the amount of lead wire method side volume.
Ball check valves are often very small, simple, and cheap. They are commonly used in liquid or gel minipump dispenser spigots, spray devices, some rubber bulbs for pumping air, etc., manual air pumps and some other pumps, and refillable dispensing syringes. Although the balls are most often made of metal, they can be made of other materials, or in some specialized cases out of artificial ruby. High pressure HPLC pumps and similar applications commonly use small inlet and outlet ball check valves with both balls and seats made of artificial ruby, for both hardness and chemical resistance. After prolonged use, such check valves can eventually wear out or the seat can develop a crack, requiring replacement. Therefore, such valves are made to be replaceable, sometimes placed in a small plastic body tightly-fitted inside a metal fitting which can withstand high pressure and which is screwed into the pump head.
There are similar check valves where the disc is not a ball, but some other shape, such as a poppet energized by a spring. Ball check valves should not be confused with Ball Valves, which is a different type of valve in which a ball acts as a controllable rotor to stop or direct flow.
A diaphragm check valve uses a flexing rubber diaphragm positioned to create a normally-closed valve. Pressure on the upstream side must be greater than the pressure on the downstream side by a certain amount, known as the pressure differential, for the check valve to open allowing flow. Once positive pressure stops, the diaphragm automatically flexes back to its original closed position.
A swing check valve or tilting disc check valve is check valve in which the disc, the movable part to block the flow, swings on a hinge or trunnion, either onto the seat to block reverse flow or off the seat to allow forward flow. The seat opening cross-section may be perpendicular to the centerline between the two ports or at an angle. Although swing check valves can come in various sizes, large check valves are often swing check valves. The flapper valve in a flush-toilet mechanism is an example of this type of valve. Tank pressure holding it closed is overcome by manual lift of the flapper. It then remains open until the tank Drains and the flapper falls due to gravity. Another variation of this mechanism is the clapper valve, used in applications such firefighting and fire life safety systems. A hinged gate only remains open in the inflowing direction. The clapper valve often also has a spring that keeps the gate shut when there is no forward pressure. Another example is the backwater valve (for sanitary drainage system) that protects against flooding caused by return flow of sewage waters. Such risk occurs most often in sanitary drainage systems connected to combined sewerage systems and in rainwater drainage systems. It may be caused by intense rainfall, thaw or flood.
A stop-check valve is a check valve with override control to stop flow regardless of flow direction or pressure. In addition to closing in response to backflow or insufficient forward pressure (normal check-valve behavior), it can also be deliberately shut by an external mechanism, thereby preventing any flow regardless of forward pressure.
A lift-check valve is a check valve in which the disc, sometimes called a lift, can be lifted up off its seat by higher pressure of inlet or upstream fluid to allow flow to the outlet or downstream side. A guide keeps motion of the disc on a vertical line, so the valve can later reseat properly. When the pressure is no longer higher, gravity or higher downstream pressure will cause the disc to lower onto its seat, shutting the valve to stop reverse flow.
An in-line check valve is a check valve similar to the lift check valve. However, this valve generally has a spring that will 'lift' when there is pressure on the upstream side of the valve. The pressure needed on the upstream side of the valve to overcome the spring tension is called the 'cracking pressure'. When the pressure going through the valve goes below the cracking pressure, the spring will close the valve to prevent back-flow in the process.
A duckbill valve is a check valve in which flow proceeds through a soft tube that protrudes into the downstream side. Back-pressure collapses this tube, cutting off flow.
A pneumatic non-return valve.
Multiple check valves can be connected in series. For example, a double check valve is often used as a backflow prevention device to keep potentially contaminated water from siphoning back into municipal water supply lines. There are also double ball check valves in which there are two ball/seat combinations sequentially in the same body to ensure positive leak-tight shutoff when blocking reverse flow; and piston check valves, wafer check valves, and ball-and-cone check valves.
Sh-type centrifugal pump repair what are the steps
Sh-type centrifugal pump is a commonly used pump, the structure of a certain representation for other pump overhaul for reference.