From Biomedical Instrumentation Systems by By Shakti Chatterjee, Aubert Miller. Published Cengage Learning, 2010, page 347.
From: Instruction Manual for the Collins Survey Spirometer, Manual No. 22168, Third Printing May 1981.
“A.1. The Survey Spirometer is a precision, calibrated, water-seal spirometer which may be used for the performance of ventilation tests.
“A.2. Figure 1 shows the basic equipment layout with all the major components identified. The spirometer body is constructed of copper while a rugged cast aluminum base supports the unit. Lightweight plastic is used for the spirometer bell.
“1.B. MECHANICAL SPECIFICATIONS
“Shipping Weight: 32 pounds.
“Net Weight: 16 pounds.
“Water capacity: 1 quart, approximately.
“B.2. Spirometer Performance Specifications:
“Kymograph: single speed, 1920 mm/min.
“Spirometer capacity: 8 liters.
“Response: +/- 1% 0-140 CPM.
“Calibration Accuracy: +/- 1% for life of bell.
“Safety: UL Listed 544”
Collins Stead-Wells spirometer. Circa 1970. Found on an Ebay listing. Although it is being sold with a soda-lime canister this is probably not part of the original system.
Collins Stead-Wells Spirometer, circa 1968.
From: Burton RM, Kozel WM, Penley RP, Ward GH, Chapman RS. Application and evaluation of portable field instruments for measuring Forced Expiratory Volume of children and adults in environmental health surveys. Environmental Health Perspectives, 1974; 8: 123-131. Page 124.