China
Africa
Explore chapters and articles related to this topic
Heating Systems
Published in Fred Hall, Roger Greeno, Building Services Handbook, 2017
For underfloor heating purposes, the thermostatic mixing valve maintains water at a constant delivery temperature by varying the proportions of hot flow water with cooler water returning via the bypass. A process known as modulating control.
A method to reduce heat strain while clad in encapsulating outerwear
Published in Journal of Occupational and Environmental Hygiene, 2018
Dennis Grahn, Megha Makam, H. Craig Heller
For protocol 4, a small closed-loop temperature-controlled circulating system was designed in house (Figure 1). The system consisted of a pump (3.6 L/min mini DC brushless submersible water pump, item # EWP-DC30A1230, Light Objects, Sacramento, CA, http://www.lightobject.com/), a wax piston-driven thermostatic mixing valve (custom designed by Rostra Veratherm, Bristol, CT), a bubble trap/expansion chamber assembly, a heat sink water perfusion pad, and the two hand interfaces, connected with plumbing fittings and laboratory tubing and powered by four AA (1.5 volt) batteries aligned in series. The path of the water flow through the system was from pump outlet to the inlet of a tee fitting. One outlet of the tee fitting connected to a water perfusion pad (23 x 13 cm) that abutted the heat sink, which in turn was connected to the cold inlet of the thermostatic mixing valve. The second outlet of the tee connected directly to the warm inlet port of the thermostatic mixing valve. The outlet of the mixing valve fed into the palmar heat exchange interfaces. The return from the interfaces flowed through the bubble trap/expansion chamber complex before returning to the inlet of the circulating pump. The bubble trap/expansion chamber assembly consisted of a 250 mL square wide mouth bottle (Nalgene) plumbed to a bubble capturing manifold. A hydration backpack (Model Lobo, Camelbak, Petaluma, CA) was used to house the water circulating system and heat sink. The heat sink was created by freezing 1 L of water contained in the hydration pack bladder (the bladder was lain flat during freezing). The wax in the thermostatic mixing valve had a melting point of 18°C. This system delivered a 600 mL/min stream of 18°C ± 2°C water to the hand interfaces. The entire system weighed < 2.25 kg (5 lb), was quiet (< 10 decibels at 10 cm), and fit under PPE outerwear.