# US 4,398,413 A · Leak detection for hermetic enclosures

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,398,413 A
- Document ID: US4398413A
- Status: Granted
- Kind: A
- Application number: 06/264,790
- Filed: 1981-05-18
- Granted: 1983-08-16
- Earliest claimed: 1981-05-18
- Assignees: Medtronic, Inc.
- Inventors: T. V. Rao
- Web page: https://patentgrep.com/patent/US4398413A

## CPC

- G01M 3/226: {for containers, e.g. radiators}
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

A method of leak testing hermetic enclosures having a penetrable, self-sealing septum communicating with the interior thereof. Test gas is introduced into the enclosure by means of a hypodermic needle inserted through the septum and then withdrawn. Subsequent monitoring of the enclosure for presence of any escaping test gas confirms if leakage is occurring.

## Claims

### Claim 1

A method for detecting leaks in a sealed enclosure, comprising the steps: providing self-sealing septum means communicating with the enclosure interior;
penetrating the septum means with hypodermic-like needle means;
evacuating the enclosure interior through the needle means;
introducing an inert gas to the enclosure interior through the needle means;
withdrawing the needle means from the septum whereby it self-seals;
placing the sealed enclosure in an evacuated test fixture in communication with means for detecting the gas; and
testing for the presence of gas escaping from the sealed enclosure.

### Claim 2 (depends on 1)

The method of claim 1 wherein:
the enclosure includes an outer plug means and the septum is disposed inwardly thereof and spaced therefrom to provide an antechamber therebetween;
the plug means is sealed in place after the gas has been admitted to the enclosure, through the septum; and
the enclosure is thereafter placed in the evacuated fixture and tested for leaks.

### Claim 3 (depends on 2)

The method of claim 2 wherein the enclosure is subjected to a "bombing" procedure prior to being tested for leaks in the evacuated fixture.