Volume change — coolant expansion between cold fill and operating temperature
Expansion Tank
15 models · single & dual chamber · PP and SS304 · 1–14.5 L
Cooling circuit
Overview
A pressurised expansion tank for the coolant circuit of a fuel-cell system. It absorbs the volume change of the coolant between cold start and operating temperature, holds the system pressure, and gives the circuit a place for entrained gas to separate. Single- and dual-chamber bodies in PP or SS304, from 1 L to 14.5 L.
Key features
- Sized on the loop — usable and expansion volumes quoted separately
- Single or dual chamber — two independent circuits in one housing
- PP for standard water-glycol coolant; SS304 where the circuit runs hot
- Custom opening pressure and port arrangement on the SS304 range
- 1311HF-SQ90L is the grade specified for hydrogen fuel-cell vehicles
Specification
Technical data
Model selection
| Model | Chamber | Total (L) | Usable (L) | Expansion (L) | Material | Working temp. |
|---|---|---|---|---|---|---|
| 1311-S1.6L | Single | 1.6 | 0.8 | 0.8 | PP | −40~120 °C |
| 1L+1L | Dual | 1.0+1.0 | 0.6+0.6 | 0.4+0.4 | PP | −40~120 °C |
| 1.7L+1.5L | Dual | 1.7+1.5 | 1.2+1.0 | 0.5+0.5 | PP | −40~120 °C |
| 1311HF-S20L | Single | 2.0 | 1.3 | 0.7 | PP | −40~120 °C |
| 1311HF-S35L | Single | 3.5 | 1.2 | 2.3 | PP | −40~120 °C |
| 4L+2.4L | Dual | 4.0+2.4 | 2.4+1.3 | 1.6+0.9 | PP | −40~120 °C |
| 1311HF-S40L | Single | 4.0 | 1.3 | 2.7 | PP | −40~120 °C |
| 1311HF-S47L | Single | 4.7 | 2.1 | 2.6 | PP | −40~120 °C |
| 1311HF-S90L | Single | 9.0 | 6.0 | 3.0 | PP | −40~120 °C |
| 1311HF-SQ90L | Single | 9.0 | 5.8 | 2.6 | PP | −40~120 °C |
| 1311HF-S150L | Single | 14.5 | 10.5 | 4.0 | PP | −40~120 °C |
| 1311HF-J20L | Single | 2.0 | 1.3 | 0.7 | SS304 | −40~120 °C |
| 1311HF-J26L | Single | 2.6 | 1.7 | 0.5 | SS304 | −40~120 °C |
| 1311HF-J4.5L+J9L | Dual | 4.5+9.0 | 3.0+3.0 | 1.5+6.0 | SS304 | −40~120 °C |
| 1311HF-J13.5L | Single | 13.5 | 9.0 | 4.5 | SS304 | −40~120 °C |
Total, usable and expansion volumes are listed separately. Choose on the usable and expansion volume the loop actually needs, then check that the body fits the space available. SS304 models allow the opening pressure and port layout to be customised.
Application
Where it is used
Gas separation — entrained air leaves the coolant before the pump
Pressure holding — the cap keeps the loop above coolant vapour pressure
Related reading
From the engineering notes
Background on the design decisions behind this component — all articles.
Cooling architecture and the insulation question
Why the coolant loop and the electrical barrier must be designed together, and which components keep them apart.
Isolated DC-DC first, then the coolant piping
The 100 Ω/V and 500 Ω/V rules come from touch-safety limits, not from the converter. Worked numbers for a 500 V stack on an 800 V bus, and what they mean for hose length and rigid tube.
Expansion Tank — product brochure (PDF)
Full specifications, model selection tables and engineering notes. Two pages, English.
Download PDF
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