Differential pressure bypass valve self-contained pressure bypass valve and electric pressure bypass valve 2 kinds.
Electric pressure bypass valve
By controlling the opening of the pressure bypass valve to control the bypass flow of chilled water, so that the pressure difference between the supply and return mains constant. Widely used in the central air conditioning set between water separators, heat pump back and forth between, can effectively keep the equipment is not damaged.
Electric differential pressure bypass valves are commonly used in gas or liquid systems to control the pressure differential between gas or liquid lines and circuits. The electric pressure bypass bypass valve installed in the system of pump accessories, when the system pressure increases and exceeds the control valve settings, the valve is then opened large, so that more water flows through the bypass valve, Thus reducing the system pressure. In contrast, the pressure drop causes the valve opening to decrease, thereby increasing the system pressure differential.
Self-operated differential pressure bypass valve
Bypass valve, also known as self-bypass pressure valve, self-pressure control valve
Self-pressure differential valve (bypass-C) in the control range automatic valve plug is closed, the pressure across the valve exceeds the preset value, the valve plug is automatically opened. And under the action of the pressure-sensitive film to automatically adjust the opening, maintaining a relatively constant pressure at both ends of the valve, rely on their own differential pressure work, without any external power, reliable performance.
Features:
Self-pressure control valve for the electric pressure control valve alternative products.
The utility model has the advantages that no external force is required and the pressure of the system itself is used to effectively improve the operational safety coefficient, which is safer and more reliable than the traditional electric differential pressure control valve. The utility model solves the problem that the electric differential pressure control valve is electrically trusted and the circuit causes problems Damage probability, and its own pressure control valve easy to install, save costs.
Self-pressure differential valve control purposes:
Self-pressure differential pressure control valve used in cold (hot) source unit protection. Installed in the set, manifold between the bypass pipe, when the user side of the part of the operation or variable volume operation, the system flow becomes smaller, resulting in increased pressure differential, the pressure exceeds the set value, the valve automatically opens part of Flow from here to ensure that the unit flow is not less than the limit value.
Self-Own own differential pressure control valve used in central heating systems to ensure that somewhere the cooling equipment does not overpressure or not emptied. For example, a system height difference larger, and regardless of the height of the district system, then press the high pressure, lower cooling equipment may be pressure explosion;
In this case, if the heat source is in the low outside, it can enter into the high division branch pipe and booster pump, and the return pipe pressure difference valve can make the pressure in the high district rise and then drop to the low district back pressure again by the valve; Can enter the low zone water supply pipe to install differential pressure valve, return booster pump, circulating water through the valve pressure to reduce back to the system.
The role and principle of bypass valve in air conditioning system:
Differential pressure air-conditioning system bypass valve is used in the chiller branch between the water trap and the main pipeline, the principle is through the differential pressure sensor to control the water trap and the water pressure across the trap , And then calculate the difference according to the measured pressure, and then by the differential pressure controller to calculate the difference and pre-set value to determine the output mode to control the valve is to increase the opening or reduce the opening to adjust Water, in order to achieve the purpose of balancing the water pressure of the host system.
Self-pressure differential valve performance parameters:
According to the user's choice to control the pressure difference.
Control of pressure in the range of 0.05 ~ 0.4Mpa can be adjusted.
Constant pressure at both ends of the valve and the control system to support user system variable flow operation. Rely on the pressure to work automatically, without external power, safe and stable operation.
Medium temperature: 0--150 ℃. Nominal pressure: 1.6Mpa.
Central air-conditioning differential pressure bypass valve role
The reduction of chilled water flow to chillers is quite dangerous. In evaporator designs, a constant water flow (or a small range of fluctuations) is often important to ensure a uniform flow of water in the evaporator tube. If the flow rate is reduced, it is inevitable that the water flow rate is not uniform, especially during some changes (Such as the head) is more likely to slow down or even flow into the flow of non-flow of "stagnant water" due to the evaporation temperature is very low in the evaporator cooling process, low velocity water or "stagnant water" extremely prone to freezing conditions Chilling damage to chillers. Therefore, the cooling capacity of the flow we require a substantially constant. On the other hand, however, from the point of view of end-use requirements, the user side requires that the water system operate at varying amounts to vary the amount of cooling (heat). The two constitute a contradiction, the most common way to solve this conflict is to set the supply and return pipe pressure bypass valve.
Its working principle is: When the system is in the design state, when all the equipments are running at full capacity, the opening of the pressure differential bypass valve is zero (no bypass water flow), then the pressure difference at the interface of the differential pressure controller (Also known as user-side, return water pressure difference) P0 is the controller's set pressure value. When the end load becomes smaller, the end of the two-way valve is closed, for the return water pressure difference P0 will increase beyond the set value, the role of pressure controller, the bypass valve will open automatically, as the bypass valve With the user-side water system in parallel, its opening will increase the supply and return pressure difference P0 decreases until it reaches P0, when stopped, part of the water flow from the bypass valve directly into the return pipe, and the user side backwater mixed Into the water pump and chiller, so through the water chiller is not changing the amount of water.
Pump operation has a high point of efficiency, the flow changes so that the motor moves around the high efficiency point, but the end result, as long as the pipe does not change the characteristics of the pump will automatically adjust to the high efficiency of the work point, we can adjust the tube Road characteristics to change the efficiency of the pump point, so that is to say, when the flow changes, the pump to continuously change their operating conditions, which led to the current changes in the period (larger or smaller), which pairs Motor operation is harmful, the inverter pump motor is easy to burn that is the result, therefore, under normal circumstances, it is best to make the pump in a stable state of operation, which requires us to bypass, regardless of the above How the load changes, the pump can run at a steady flow, without causing the motor current changes over time, so that the life of the motor decreases.
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