美国舒稳ZW209自动控制阀
ZW209 Pressure Reducing Valve

可以。ZW209可以在现场被更换成ZW209E。请联系您的美国舒稳公司威金斯（Wilkins）销售代表，他们将告诉您在现场更换过程中需要预备的必备件。

Yes. The ZW209 can be converted to a ZW209E in the field. Contact your Zurn Wilkins Representative, and they will guide you in the process to get the necessary components for your field conversion.

为了正确选择减压控制阀的恰当型号，必须事先了解要安装此阀门的系统实际的及所期望的水力特性。实际的进水口压力、所期望的出水口压力、以及最大和最小流量等参数都必须确定。利用《规格型号提交表》（Specification Submittal Sheet）（在美国舒稳公司官方网站上寻找），选择所选型阀门需要满足的系统最大和最小连续流量。要确保此阀门不是位于潜在的空穴区域。利用美国舒稳公司威金斯（Wilkins）的《空穴图表》（Cavitation Chart）（还是在美国舒稳公司官方网站上寻找），确认通过此阀门的所期望压降不会落入空穴区域。如果通过一个单独阀门的压降导致落入空穴区域，则串联使用两个减压控制阀能够确保不落入空穴区域。由串联的两个阀门产生的压降，每一个阀门都能够以相同的方式平均降压。这种方法确保空穴现象不会发生，并且有利于明显延长阀门的使用寿命。如果需要了解有关自动控制阀的更多知识，请浏览美国舒稳公司网站的下列链接网页http://www.zurn.com/Pages/CategoryHierarchy.aspx?NodeKey=421244（注：经测试，此链接在中国大陆打不开！）。

In order to properly size a Pressure Reducing Automatic Control Valve, one must know the actual and desired hydraulic characteristics of the system where the valve will be installed. The actual inlet pressure, desired outlet pressure, and the maximum and minimum flow rates must be determined. Utilizing the Specification Submittal Sheet (found at zurn.com), choose the size of valve that will satisfy the maximum and minimum continuous flow rates of the system. Ensure that the valve will not be in a potential cavitation zone. Utilizing the Zurn Wilkins Cavitation Chart (also found at zurn.com), make certain that the desired pressure drop across the valve does not fall into the cavitation zone. If the pressure drop across a single valve does result in cavitation, the use of two Pressure Reducing Control Valves piped in series would be warranted. With pressure reduction performed by two valves in series, each valve is set such that the pressure is dropped in fairly equal steps. This method ensures that cavitation will not occur, and serves to drastically increase valve longevity. For more information on Automatic Control Valves, please visit our web site at http://www.zurn.com/Pages/CategoryHierarchy.aspx?NodeKey=421244

当气体被夹带进入阀门，将产生颤动、震动以及压力波动。为了确保阀门运行正常，必须排出气体。松开阀帽中间的塞子，直到所有气体被排出。这将确保阀门能够稳定运行。如果需要了解更多的产品信息，请浏览美国舒稳公司网站中下列链接的网页http://www.zurn.com/Pages/ProductDetails.aspx?NodeKey=424543（注：经测试，此链接在中国大陆打不开！）应用产品：所有自动控制阀。

Air entrained in the valve will result in chattering, pulsations, and pressure swings. The air must be bled out for the valve to function correctly. Loosen the plug in the center of the bonnet until all air is removed. This will stabilize the valve. For more product information, please visit our web site at http://www.zurn.com/Pages/ProductDetails.aspx?NodeKey=424543 Applicable products: All Automatic Control Valves

如果减压自动控制阀的水流量小于最小连续流量，常用的处理方法是，用一个直接作用减压阀（PRV）与减压自动控制阀（ACV）并联使用。需要选择在压力减少大约5 psi时能够保持适当的流量的直接作用减压阀（PRV）。当与减压自动控制阀（ACV）并联安装时，直接作用减压阀（PRV）设置为系统所需的期望静态运行压力。然后设置减压自动控制阀（ACV）的压力比直接作用减压阀（PRV）小5 psi。这就确保所有低流量，从零至减压自动控制阀（ACV）的最小连续流量，都将从直接作用减压阀流过。当通过直接作用减压阀（PRV）的流体压力降低到减压自动控制阀（ACV）的设置点，减压自动控制阀（ACV）将开始打开，并且通过流体，直到达到最大连续流量值。这种方法确保流量从零流量不间断到最大流量各个阶段都能够正常运行。如果需要了解有关自动控制阀的更多知识，请浏览美国舒稳公司网站的下列链接网页http://www.zurn.com/Pages/CategoryHierarchy.aspx?NodeKey=421244（注：经测试，此链接在中国大陆打不开！）。

Water flows under the minimum continuous flow rate for the Pressure Reducing Automatic Control Valve are generally handled by a Direct Acting Pressure Reducing Valve (PRV) piped in parallel to the Pressure Reducing Automatic Control Valve (ACV). The PRV is sized according to its ability to flow the proper rate with a fall-off of approximately 5 psi. When installed in parallel with the ACV, the PRV is set to the desired static operating pressure required by the system. The ACV is then set 5 psi below the setting of the PRV. This ensures that all low flows, from zero up to the minimum continiuous flow rate of the ACV, will flow through the PRV. When the flowing pressure through the PRV drops to the set point of the ACV, the ACV will begin to open and provide flow up to its maximum continuous rated flow. This method provides a seamless flow rate from zero up to the maximum. For more information on Automatic Control Valves, please visit our web site athttp://www.zurn.com/Pages/CategoryHierarchy.aspx?NodeKey=421244