Septum Magnet Water Flow Measurement

To properly operate a resistive magnet, cooling water needs to be run through the coils of the magnet. This ensures the magnet doesn’t get too hot, which would raise the resistance, and therefore raise the power dissipated by the magnet, which raises the temperature of the magnet. To make sure we have appropriate water cooling capabilities in the Hall for each magnet, it is important we know how much flow the magnet requires. To measure the flow I used a GPI TM series flow meter. In the Test Lab, where I have the test setup, the high side pressure is 125 psi and the low side pressure is 35 psi, giving a pressure differential of 90 psi. To determine the pressure, I connected the test setup to one of the connectors, and opened only the inlet valve. This gave me 125 psi. Next I closed the inlet valve, and opened only the outlet valve. This gave me 35 psi. I put the 90 psi pressure differential across each section of conductor on each coil to measure the full flow. Then I took one section of conductor and varied the inlet pressure to see how much flow was present at a given pressure drop.

I measured each section of conductor individually for each of the four coil sets. The typical flow through a single conductor section is ~1.60 GPM with the pressure drop of 90 PSI.

Figure 1. Septum Magnet Coils Labelled. Each coil has 8 sections of conductor.

Figure 2. Left: Front connections numbered. Right: Side connections numbered.

Flow Rate(GPM)	Section 1	Section 2	Section 3	Section 4	Section 5	Section 6	Section 7	Section 8
Coil A	1.60	1.61	1.61	1.60	1.57	1.55	1.60	1.61
Coil B	1.61	1.61	1.61	1.59	1.57	1.57	1.60	1.62
Coil C	1.63	1.63	1.61	1.59	1.57	1.58	1.61	1.63
Coil D	1.66	1.63	1.62	1.61	1.60	1.58	1.63	1.60

Table 1. Flow through each individual section of conductor.

Next, I varied the pressure by turning the valve part way off to reduce the pressure at the inlet, and then measured the inlet pressure and the flow through the conductor section. For this procedure, I assumed the outlet pressure was not dependent on the flow through the conductor.

Pressure Drop(psi)	10	25	35	49	54	60	66	71	75	80	85	90
Flow(GPM)	.46	.82	.98	1.18	1.22	1.30	1.38	1.43	1.47	1.52	1.56	1.60

Table 2. Flow through a single coil section with varying pressure drop.

Figure 3. Flow vs Pressure drop through conductor A1.