Note 16 - Segment and Related Information - Information by Industry Segment (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Sales	$ 23,816,735	$ 6,645,780	$ 5,852,924
Income (Loss) Before Provision for Income Taxes
Income (loss) before provision for income taxes	2,188,760	1,333,248	(122,377)
Operating Segments [Member]
Sales	23,816,735	6,645,780	5,852,924
Operating Segments [Member] | Commercial Air Handling [Member]
Sales	11,190,844
Income (Loss) Before Provision for Income Taxes
Income (loss) before provision for income taxes	1,424,878
Operating Segments [Member] | Test and Measurement [Member]
Sales	6,610,684	4,884,778	5,852,924
Income (Loss) Before Provision for Income Taxes
Income (loss) before provision for income taxes	1,859,936	143,021	940,016
Operating Segments [Member] | Industrial Hose [Member]
Sales	6,015,207	1,761,002
Income (Loss) Before Provision for Income Taxes
Income (loss) before provision for income taxes	595,939	166,075
Corporate, Non-Segment [Member]
Income (Loss) Before Provision for Income Taxes
Income (loss) before provision for income taxes	$ (1,691,993)	$ 1,024,152	$ (1,062,393)