ISO 12809:2020 Crop protection equipment — Reciprocating positive displacement pumps and centrifugal pumps — Test method. 7 Test methods 7.1 General Before starting the tests, ensure visually that all connections work properly without leakage at the maximum pressure and without unintended air intake at the maximum depression in the suction line. If present, set the pressure of the pneumatic pressure pulsation damper as indicated by the manufacturer. Use the test liquid specified in Clause 5. 7.2 Stand-alone pump 7.2.1 Test bench 7.2.1.1 The test bench shall have a main circuit containing the devices for flow control and pressure adjustment; see Figure 1 with the scheme of hydraulic circuit for self-priming pump or Figure 2 with the scheme of hydraulic circuit for non-self-priming centrifugal pump. To simulate the installation of positive displacement pump on the sprayer, the test bench shall have an extra circuit (key A in Figure 1) with part of the flow coming back directly to the suction line of the pump. 7.2.1.2 The suction line connects the pump with the tank. It shall be fitted with an air inlet valve (key 4 in Figure 1 or Figure 2), a suction pressure adjustment valve (key 6 in Figure 1 or key 5 in Figure 2) and a suction pressure gauge (key 7 in Figure 1 or key 6 in Figure 2). For self-priming pumps, the h value shall be (400 ± 100) mm (Figure 1). For non-self-priming pumps, the h value shall be (—400 ± 100) mm (Figure 2). The inlet of the suction line shall be free, without non-return valves. 7.2.1.3 The delivery line shall be fitted with a safety valve (key 9 in Figure 1) with appropriate range able to protect the test bench, a pressure gauge (key 10 in Figurel or key 8 in Figure 2), a device for flow- rate measurement (key 11 in Eigure1 or key 9 in Figure 2) and a pressure adjustment valve (key 12 in Figure 1 or key 10 in Figure 2). The output of the delivery line shall he connected to the tank in order to guarantee the re-circulation of the test liquid (key 13 in Figure 1 or key 11 in Figure 2). Ensure that the back flow does not create turbulence in the suction line. 7.2.1.4 The extra circuit (key A in Figure 1) shall be fitted with a re-circulation adjustment valve (key 14 in Figure 1)...
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