Rummel WFR 90: the simplest way to see the flow in mold circuits
The WFR 90 is a mechanical water flow regulator designed for the mold cooling circuits that run next to the injection molding machine. It shows the flow of each circuit and the temperature of its return water separately; the operator sees which circuit is getting too little water just by looking at the front of the unit. It needs no electrical connection, no software and no parameter setting. This simplicity makes it the most frequently chosen entry-level solution for standard cooling water applications.
How is the flow measured?
The unit works on the variable area principle. Measurement takes place in the return line of the mold circuit: the water coming back from the circuit lifts a cone inside a transparent tube, and the height of the cone shows the flow. Measuring on the return side has a practical meaning: the reading shows whether the water actually passes through the mold. If the supply side has pressure but the channel inside the mold is blocked, the cone on the return side reveals it immediately.
Each circuit has manually adjusted regulating valves on the supply and return lines; the flow is balanced circuit by circuit with these valves. A thermometer is standard equipment.
Materials and design
- Measuring tube: polyamide (PA12)
- Housing: polyamide reinforced with 30% glass fiber
- Internal tie rods: stainless (VA) steel
- O-rings in contact with water: EPDM
- Female thread: 3/8", brass
The plastic housing and the PA12 tube keep the unit light and compact; on the other hand, they also set its temperature limit. The 90 in the name WFR 90 is the upper limit of the unit's thermal resistance.
Pressure and temperature must be read together
On the WFR 90, the permissible pressure drops as the water temperature rises. For a circuit running on cooling tower or chiller water, 8 bar leaves a sufficient margin, while for a mold circuit running on 80 °C hot water the limit falls to 5 bar. Before ordering the unit, compare the outlet pressure of your temperature control unit with this table.
| Max. pressure | Max. temperature |
|---|
| 8 bar | 40 °C |
| 7 bar | 60 °C |
| 5 bar | 80 °C |
| 4 bar | 90 °C |
Two housing types and 12 models
The WFR 90 comes with two connection types: the ZR housing has 3/8" threaded connections, the ZS housing has Ø 12 mm hose connections. The number of circuits is selected between 1 and 12; each additional circuit makes the unit about 53 mm wider.
| ZR type (3/8" thread) | ZS type (Ø 12 mm hose) | Number of circuits | Width (mm) |
|---|
| WFR 01 ZR | WFR 01 ZS | 1 | 73 |
| WFR 02 ZR | WFR 02 ZS | 2 | 126 |
| WFR 03 ZR | WFR 03 ZS | 3 | 179 |
| WFR 04 ZR | WFR 04 ZS | 4 | 231 |
| WFR 05 ZR | WFR 05 ZS | 5 | 284 |
| WFR 06 ZR | WFR 06 ZS | 6 | 339 |
| WFR 07 ZR | WFR 07 ZS | 7 | 392 |
| WFR 08 ZR | WFR 08 ZS | 8 | 444 |
| WFR 09 ZR | WFR 09 ZS | 9 | 497 |
| WFR 10 ZR | WFR 10 ZS | 10 | 552 |
| WFR 11 ZR | WFR 11 ZS | 11 | 607 |
| WFR 12 ZR | WFR 12 ZS | 12 | 659 |
Technical data
| Feature | Value |
|---|
| Measuring principle | Variable area measurement, cone in the return line |
| Max. flow per circuit | 720 L/h |
| Number of circuits | 1–12 |
| Max. temperature | 90 °C |
| Max. pressure | 8 bar (40 °C) – 4 bar (90 °C) |
| Connection | ZR: 3/8" thread · ZS: Ø 12 mm hose |
| Circuit control | Manual regulating valve on supply and return |
When the WFR 90, when a higher model?
If your mold temperature is below 90 °C and the number of circuits does not exceed 12, the WFR 90 is sufficient. If you go above 90 °C with hot water, the brass-bodied RWFR120 or RWFR160 is the right step; if you want alarms and data logging, the Flow Control retrofit kit is.
