To ensure the safe and stable operation of pressurized fluid pipelines for gas or liquids a one-way check valve arrangement can be installed to ensure that backflow does not occur. A variety of structural types of one way check valve suitable for gas or liquid are available in the market.
In the process of pulverized coal pressurized combustion, gasification, etc., generally pulverized coal is pressurized and delivered through a conveying line to pressure reactor. During normal operation, the pressure in the source of pulverized coal is higher than reactor pressure, thus the gas-solid mixture flows continuous towards the reactor. However, in unusual circumstances, such as a sudden drop in upstream pressure, or mechanical damage along the transport pipeline and before any instrumentation detects and implements control measures, the hot reactor materials may flow back into the fluid conveying line. This is definitely not allowed in a production setup. For high-pressure high-temperature reactors, high-temperature materials backflow to a metal line may result in disastrous consequences. Therefore, the solid delivery pipeline also needs to equipped with a check valve or similar device, in order to ensure secure delivery of materials.
Unlike the use of check valves for gas and liquid pipelines, if a traditional check valve is used in a solid flow, the solid particles may reach and remain within the valve. The accumulation of said solid particulates may result in partial or complete loss of function of check valve. Further, the solid-containing fluid line may suffer erosion problems. The solid concentration and the velocity of fluid are major factors contributing to erosion of the valve body. The conventional type of check valve uses a flow barrier component to dynamically throttle flow area (induce higher velocity) and generate a flow pressure difference across the barrier to balance with a force, for example, the weight of the barrier component. The flow barrier component is set such that it only move towards one direction and holds tight if flow from other direction occurs. The flow barrier generally changes the fluid flow direction inside the valve body, and the changed flow direction is normally random. The higher velocity around the barrier component and the flow direction change all contribute significantly to the erosion of valve body, once there are solids particles present, leading to the damage of the valve body. Malfunction and erosion of the check valve caused by solid particles increases the complexity of designing suitable solids fluid check valves.