并联安装
Parallel Installations

　　两个或以上的系列709装置能够以并联的方式安装在管道（认可的区域）上，用于服务于更大的主供应管道。对于切断管路进行检测和维修，但又必须保持连续的流体供应的应用场合，就需要配置这种类型的安装。这种安装类型也具有提供性能的优点，能够提供的性能超过单个阀门所能够提供的性能。
　　Two or more Series 709 devices may be piped in parallel (where approved) to serve a large supply pipe main. This type of installation is employed whenever it is vital to maintain a continuous supply of water where interruptions for testing and servicing would be unacceptable. It also has the advantage of providing increased capacity where needed beyond that provided by a single valve.
　　对于两个阀门的安装，装置的总体性能应该等于或超过系统所需的性能。性能表所显示的所需系列709装置的通径符合特定性能。并联结构所采用的装置数量应该由工程师根据特定安装的运行环境做出决定。
　　For two valve installations the total capacity of the devices should equal or exceed that required by the system. Capacity table shows the size of the No. 709 devices required to meet a certain capacity. The quantity of devices used in parallel should be determined by the engineer's judgement based on the operating conditions of a specific installation.

　　下列检测程序是在美国广泛使用的防回流阀性能检测程序中的一种。
　　The following Test Procedure is one of several that is recognized throughout the United States for verification of the functioning of Backflow preventers.
　　下列检测程序并不是特定的建议。美国瓦茨检测组件系列能够执行任何广泛采用的防回流阀检测程序。
　　The following procedure is not a specific recommendation. The Watts series of test kits are capable of performing any of the recognized Backflow test procedures.

1. 冲洗所有测试旋塞
   Flush all test cocks
2. （在连接软管之前）打开检测器。检测器上的所有读数必须是零。关闭VA和VB。
   Turn tester on (before connecting hoses). Tester must read all zeroes. Close VA and VB.

TK-DP检测组件
TK-DP Test Kit

检测1号 - 检测1号止回阀
Test No. 1 - Test No. 1 Check Valve

1. 在测试旋塞2号和检测器连接A之间安装高端软管。
   Install high side hose between testcock No. 2 and tester connection A.
2. 在测试旋塞3号和检测器连接B之间安装低端软管。
   Install low side hose between testcock No. 3 and tester connection B.
3. 依次开启测试旋塞2号、VA和防气软管，然后关闭VA。
   Open testcock No. 2 then VA, bleed hose then close VA.
4. 依次开启测试旋塞3号、VB和排气软管，然后关闭VB。
   Open testcock No. 3 then VB, bleed hose then close VB.
5. 在VB和测试旋塞1号之间安装一个旁路软管。开启测试旋塞1号，通过放松VB上的软管连接来排气。紧固软管连接，完全打开VB。
   Install a bypass hose between VB and testcock No. 1. Open testcock No. 1 and bleed by loosening hose connection at VB. Tighten hose connection, fully open VB.
   推 - 印刷头（等待），然后推 - 开始检测
   Push - Print Head (wait) then Push - Start Test
6. 关闭关闭阀2号，然后关闭关闭阀1号。
   Close shutoff valve No. 2 then No. 1.
7. 缓慢开启VA，高端压力比低端压力降低2 psid左右（不同读数大约在2.0 psid左右）。关闭VA。如果读数继续保持，则记录为“紧”。如果读数变为0，而且压力A增加到压力B，则这个止回阀就记录为泄漏。如果读数变为+psid，则2号关闭阀就有过量的泄漏，并且必须更换并检测这个阀门。
   Slowly open VA and lower high side pressure about -2 psid below the low side pressure (differential reading about -2.0 psid). Close VA. If reading is maintained, record as "tight". If reading returns to 0 and the pressure A increases to pressure B, the check is recorded as leaking. If the reading returns to +psid, No. 2 shutoff valve is leaking excessively and must be replaced to test the valve.
8. 关闭所有测试旋塞，从测试旋塞2号、测试旋塞3号和测试旋塞1号上拆卸软管。重新开启关闭阀1号。进入检测2号。
   Close all test cocks, remove hoses from testcock No. 2 and testcock No. 3 and testcock No. 1. Reopen shutoff valve No. 1. Proceed to Test No. 2.
   推 - 停止检测。
   Push - Stop Test.

检测2号 - 检测2号止回阀
Test No. 2 - Test No. 2 Check Valve

1. 在测试旋塞3号和检测器连接A之间安装高端软管。
   Install high side hose between testcock No. 3 and tester connection A.
2. 在测试旋塞4号和检测器连接B之间安装低端软管。
   Install low side hose between testcock No. 4 and tester connection B.
3. 依次开启测试旋塞3号、VA和排气软管，然后关闭VA。
   Open testcock No. 3 then VA, bleed hose then close VA.
4. 依次开启测试旋塞4号、VB和排气软管，然后关闭VB。
   Open testcock No. 4 then VB, bleed hose then close VB.
5. 在VB和测试旋塞1号之间安装一个旁路软管。开启测试旋塞，并通过松开VB上的软管连接进行排气。紧固软管连接，完全打开VB。
   Install a bypass hose between VB and testcock No. 1. Open testcock No. 1 and bleed by loosening hose connection at VB. Tighten hose connection, fully open VB.
   推 - 开始检测
   Push - Start Test
6. 关闭关闭阀1号。
   Close shutoff valve No. 1.
7. 缓慢开启VA，高端压力比低端压力降低2 psid左右（不同读数大约在2.0 psid左右）。关闭VA。如果读数继续保持，则记录为“紧”。如果读数变为0，而且压力A增加到压力B，则这个止回阀就记录为泄漏。如果读数变为+psid，则2号关闭阀就有过量的泄漏，并且必须更换并检测这个阀门。
   Slowly open VA and lower high side pressure about -2 psid below the low side pressure (differential read ing about -2.0 psid). Close VA. If reading is maintained, record as "tight". If reading returns to 0 and the pressure A increases to pressure B, the check is recorded as leaking. If the reading returns to +psid, No. 2 shutoff valve is leaking excessively, and must be replaced to test the valve.
   推 - 停止检测
   Push - Stop Test.