Selection of slurry pump outlet check valve.
1.Under the engineering conditions of the general slurry pumping station, the selection of the check valve at the outlet of the slurry pump should follow the following principles.
2.For slurry pump outlet pipes with a small diameter, a lift check valve should be used when the DN<50 mm.
3.The pipe with a diameter of DN 50mm at the outlet of the slurry pump should be equipped with a swing-open check valve. Swing check valves can be installed horizontally or vertically. The disc of a swing check valve rotates around the axis of rotation, and its fluid resistance is generally smaller than that of a lift check valve. It is suitable for larger diameters. There are no restrictions on where to install. It is usually installed on top of a horizontal pipe. It is suitable for larger diameters. According to the number of valve discs, it can be divided into three types: single-lobe swing type, double valve swing type and multi-valve swing type. Single-disc swing-start check valves are typically used in medium diameter applications. When a single-lobe swing-open check valve is selected for large-diameter pipelines, in order to reduce the water hammer pressure, it is best to use a slow-closing check valve that can reduce the water hammer pressure. The double-flap swing check valve is suitable for large and medium diameter pipes. The clamp-on double-flap swing-open check valve has a small structure and light weight, and is a fast check valve. Multi-lobe swing check valves are suitable for large diameter pipes.
2.A check valve is installed at the outlet of the slurry pump.
1.Swing-start check valves are generally installed on horizontal pipes: check valves with a diameter of DN 80 mm can also be installed on vertical or upward-inclined pipes.
2.Straight-through lift check valves should be installed above horizontal pipes. Vertical lift check valves must be installed on vertical pipes with the medium flowing from bottom to top.
3.Since the check valve can be easily damaged, the check valve should be installed close to the slurry pump outlet. The check valve has a shut-off valve (usually a ball valve or gate valve) in the lower part for easy service.
4.In order to facilitate the pressure relief after the check valve is removed, if the check valve itself does not have a relief valve, a pressure relief valve should be installed between the check valve and the globe valve.
3.Protective measures to prevent hydraulic shock from damaging the sealing surface of the check valve.
The setting of the check valve prevents the backflow of the material and prevents the slurry pump impeller from being hit by the liquid. However, in the case of the check valve itself, improper setting can cause the disc to suddenly impinge on the seat caused by water hammer, damaging the sealing surface of the check valve. Therefore, the following protective measures should be taken:
1.The swing-open check valve with less than 80mm at the outlet of the slurry pump should be installed horizontally to reduce the return and impact of the valve disc.
2.For pipelines with a diameter of less than or equal to 150mm for the outlet check valve of the slurry pump, a bypass should be set around the check valve to prevent the pressure behind the valve from rising too high and causing damage to the sealing surface of the check valve.
3.For the pipeline with high pressure at the beginning and end of the slurry pump discharge pipeline, and no bypass is allowed, the following measures can be taken:
1.Set up a safety valve and replace the side valve. It functions similarly to a side pass valve. It is located near the outlet of the check valve. When water hammer increases the pressure, a portion of the water can be released to prevent damage caused by further pressure increases.