Nitrogen water hammer pressure relief valve?as a control valve which are used for high pressure power plant or boiler. There are two types of cylinder control type and electrical system control type.Cylinder controlled nitrogen water hammer pressure relief valve belongs to active pressure relief valve.(Find the structure as follow).?The driving force is the pressure provided by the high-pressure nitrogen gas source bottle,cast steel valves or stainless steel valves are installed in parallel on the pipeline. The upstream side of the stainless steel valve is connected to the pipeline, and the downstream side is connected to the relief line.
The gas cylinder controlled nitrogen water hammer pressure relief valve is mainly composed of four parts, the main valve, pipeline instruments and accessories, temperature difference suppression bottle and gas source bottle.The high-pressure nitrogen provided by the gas source bottle enters the inner cavity of the main valve through the pipeline and the control instrument to control the opening and closing of the main valve.The temperature difference suppression bottle is similar to the main valve air chamber through the pipeline, and usually uses deep burial or other thermal insulation measures to reduce the effect of temperature changes on the pressure in the air chamber.
The electrical system control structure is more complicated than the gas cylinder control type, and the cost is relatively expensive, External power supply required. Electrical system controlled nitrogen water hammer pressure relief valve can realize active switching of nitrogen cylinder. It has lots of advantages such as active temperature correction compensation, Overpressure alarm, Air source low pressure alarm. A set of control system can supply gas to multiple stainless steel valves and other functions, suitable for areas with high pipeline initiative and sparsely populated areas.
The main valve of the nitrogen-type water hammer pressure relief valve is an axial flow structure. It is divided into three parts: the main valve inlet is connected with the upstream pipeline, the gas chamber inside the main valve is connected with the gas chamber pipeline and control instrument, and the main valve outlet is connected with the relief pipeline. Under normal working conditions, the nitrogen water hammer pressure relief valve is shown in the figure below
After the high-pressure nitrogen source passes through the air chamber pipeline and the control instrument, the system pressure commensurate with the set pressure is added to the air chamber of the water hammer valve.The main valve flap is in contact with the sealing element under the pressure of the system to maintain the closed state.When water hammer occurs in the pipeline, the pressure of the upstream pipeline exceeds the set pressure of the stainless steel valve, the flap is pushed and moves to the left, and the volume of the inner cavity of the water hammer valve becomes smaller. See the picture as bellow
At this time, the main valve is opened, and part of the medium in the pipeline is quickly released into the pressure relief tank, thereby reducing the water hammer pressure peak, and playing the role of cherishing the pipeline and equipment. With the opening of the water hammer relief valve, the energy of the water hammer wave is released. When the pipeline pressure drops below the set value of the water hammer pressure relief valve, under the effect of the system pressure, the main valve flap comes into contact with the sealing element again to realize the closing process of the stainless steel valve and return to normal working conditions.
