The Emerson Climate Technologies Flow Controls was established back in the days when ammonia and carbon dioxide were almost the only refrigerants used – long before air conditioning had become an important part of the refrigeration industry. That is when the ALCO Valve Company was pioneering the control of refrigerant flow. The only ALCO product at that time was an automatic constant pressure expansion valve for ammonia. This first valve was a great step forward in refrigerant flow – it eliminated the need for constant personal attention on refrigerating systems. ALCO's first factory was in a basement room. However, the company’s first product met with such immediate acceptance that, in less than a year, a larger facility was needed.
During ALCO's first year, only 500 units were produced. World War II spurred production of these controls as well as the development of ALCO products for other fields. Soon, aircraft hydraulic controls and actuating devices, radio direction finders, and aircraft windshield wipers (now carried by BF Goodrich) were in production. Throughout the war, ALCO was a proprietary supplier of refrigerant flow controls to the U.S. Navy and Maritime Commission for surface and subsurface vessels. After the war, demand for ALCO's diversified products grew rapidly. Research for new products went steadily forward, and a new concept in refrigeration control was realized with a mechanical pressure-limiting expansion valve. From drawing boards and laboratories came 4-way reversing valves, refrigerant distributors, and many other new refrigerant controls.
Emerson Electric Co. acquired ALCO in 1967; ALCO quickly began broadening its operations. Today, former ALCO products are manufactured by Emerson Climate Technologies Flow Controls under the Emerson brand. Emerson's main emphasis has been on technical advances and new products in the field from which it took its original name: "Automatic Liquid Controls'" for the refrigeration and air conditioning industries. Emerson is now aggressively developing control devices for new industrial and electronic markets. Hundreds of customers representing highly diversified companies throughout the world use Emerson valve, control and system protector products.