Spring Valve From the Database

This tutorial runs a full selection on the built-in sample data, so you can follow it without having any data of your own. It takes about twenty minutes and costs six solver runs.

Unlike Quick Start, which gets you a number, this one gets you a decision, including the checks that tell you whether to trust it.

The numbers below are reproducible. If yours differ, something in your setup differs.

The Case

You are protecting a 30 litre pack. Propagation testing says you must survive five cells venting. Structural analysis rates the enclosure at 20 kPa above ambient, and the candidate valve is the S001 spring valve with a 5 kPa setpoint.

The question is how many of them you need.

Step 1: Build the Case

Set every field in the table above. Two of them differ from the defaults, so check them specifically: Max Pressure Limit must read 20, not 50, and Number of Venting Cells must read 5, not 1.

Under Cell Venting Data, click Browse database… and pick Demo-NCM-40Ah. Under Pressure Relief Valve Characteristic, click Browse database… and pick S001. Leave Number of Valves at 1.

The toolbar’s Simulation Time should read 25, set automatically from the venting curve: the curve runs for 15 s, and the tool adds 10 s so you can see the valve close and the pressure come back down.

Step 2: Run the Baseline

Click Run.

One valve is not enough. The peak overshoots the 20 kPa enclosure limit by almost 40 %.

Look at the charts before moving on, because the shape matters. Open Four Grid. The valve opens almost immediately, at 0.248 s, and yet pressure keeps climbing for several more seconds. That is the signature of a valve that opened in time but cannot pass gas fast enough. The problem is flow capacity, not setpoint, which immediately tells you that a lower setpoint valve would not have helped.

Step 3: Add a Second Valve

Change Number of Valves to 2. The results clear and the console warns that inputs changed. Click Run.

Two valves pass, at 12.047 kPa against a 20 kPa limit. Note that the opening time barely moved, from 0.248 s to 0.251 s. Adding a valve does not change when relief starts, only how much of it there is.

Step 4: Ask Whether a Third Helps

Change Number of Valves to 3 and run again.

The second valve was worth 15.7 kPa. The third is worth 2.5 kPa. You are on the flat part of the curve, and a fourth would buy less still.

This is the single most useful thing the screen tells you. If your design only passed because of a third and fourth valve, the margin would be an artefact of stacking hardware rather than a real cushion, and the next revision of your venting data would erase it.

Set Number of Valves back to 2. That is the candidate.

Step 5: Test the Margin

A pass is not a result until you know what would break it. Three checks, one run each, all against the two valve configuration.

More Cells Than Required

Set Number of Venting Cells to 6 and run.

Relative peak: 13.574 kPa. Adding a sixth cell costs 1.5 kPa. The design tolerates being wrong about the propagation count by at least one cell, which is reassuring.

Set it back to 5.

Hotter Gas

Set Initial Temperature to 200 °C and run.

Relative peak: 19.923 kPa, against a 20 kPa limit.

This is the check that matters. The 25 °C baseline was an assumption, not a measurement, and vented gas is not at ambient temperature. Simply assuming the gas is hot consumes the entire margin the second valve bought you.

Set it back to 25 °C.

Less Void Volume

Set Void Volume in Pack to 20 L and run.

Relative peak: 12.057 kPa, against 12.047 kPa at 30 L. Essentially no change.

That looks wrong until you think about the mechanism. Once the valve is relieving, the peak is set by the balance between gas arriving and gas leaving, and neither depends on how much room the gas has. The void volume changes how quickly pressure gets there, not where it settles. Void volume dominates only in cases where the valve barely opens.

Set it back to 30 L.

Step 6: The Decision

Two S001 valves is the answer, with one condition attached: the result depends almost entirely on the gas temperature assumption, and 25 °C is not defensible for vented gas. Before this goes into a design freeze, you need either a measured pack gas temperature or a deliberately conservative assumed one.

That condition is the real output of this tutorial. The tool did not just give you a valve count, it told you which unknown your decision is resting on and therefore what your test programme has to measure.

Step 7: Keep the Evidence

With the final configuration on screen and re-run:

1. Save / Load → Save Configuration for the exact inputs.
2. Export → Export Data (CSV) for the full resolution numbers.
3. Export → Download Report (PDF) for the review.

Nothing is stored on our servers, so these three files are the entire record. See Saving and Loading a Setup.

Next

• Membrane Valve From CSV runs the same kind of case on data you upload yourself.
• Choosing a Valve is this procedure written as a general method.