2000 Hook-up Book

Temperature Control Valves for Steam Service

Steam Injector Unlike a sparge pipe, a steam injector is a manufactured device that draws in the cold liquid, mixes it with steam within the injector nozzle and distributes the hot liquid throughout the tank.

Case in Action: Cheese Production The circulation induced by the injector will help ensure thorough mixing and avoid temperature stratification. See Fig. II-43 (page 105) for a typical injector installa tion. Other advantages of the

injector over a sparge pipe is reduced noise levels and the abil ity to use high pressure steam up to 200 psig. Refer to applicable technical information sheets for sizing and selection information.

SYSTEM DESIGN

Fine steam filtration in the preparation of cheese production is important to the quality of the final product. Because the pro ducer of cheese products was heating cheese vat washdown water by direct steam injection, a filtration device was added to enhance product quality by filtering out the particulates. While pleased with this simple method of heating, there was some concern that any particulates entering the wash down water during steam injection may ultimately contaminate the vats being cleaned, affecting the cheese production. Solution Direct steam injection was the best solution for the cheese producer, but the concern about the contamination was very important. • A separator was installed in the incoming steam supply line, which removes a high percentage of the entrained moisture. A fine mesh screen strainer was installed to remove solid particulate matter. • A pneumatically actuated two port valve was installed to control tank temperature. The unit throttles the flow of steam to the tank based on the signal being transmitted by the temperature controller. • Having removed the entrained moisture and majority of par ticulate matter from the steam supply, a cleanable CSF16

stainless steel steam filter was installed which is capable of removing finer particles smaller than 5 microns in size. • A vacuum breaker was added to the system in order to prevent any of the heated water being drawn back up into the filter during certain periods of operation. • A stainless steel injector system was installed which is capable of efficiently mixing large volumes of high pressure steam with the tank contents with little noise or tank vibration. (The customer stipulated the reduction of noise levels in the production facility.) Benefits: • Guaranteed steam purity and assured compliance with the 3-A Industry Standard • Inexpensive installation compared with alternative heat exchanger packages available • Cleanable filter element for reduced operating costs (replacement element and labor costs). • Accurate temperature control using components of the existing system • Quiet and efficient mixing of the steam and the tank contents • Product contamination is minimized, the cost of which could be many thousands of dollars, loss of production or even consumer dissatisfaction.

Temperature Control Valves for Liquid Service

3-Port Piston-Balanced. This valve is piped either for hot/cold mixing or for diverting flow between two branch lines. Pneumatically Operated Valves As with direct operated valves, the pneumatically operated types have the same three groups. The major difference is they require an external pneumatic or electric (through a positioner or convert er) signal from a controller. Heating And Cooling Loads Formulas for calculating the heat ing or cooling load in gallons per minute of water are: Heating Applications: a. Heating water with water Heating water GPM required = GPM (Load) x TR ∆ T 1

Temperature control valves for liquid service can be divided into two groups. Normally associated with cooling, these valves can

b. Heating oil with water

Heating water GPM required = GPM (Load) x TR 2 X ∆ T 1 Heating water GPM required = CFM x TR 400 x ∆ T 1

also be used on hot water. Direct Operated Valves

c. Heating air with water

Three types are available for liq uid service and a selection would be made from one of the follow ing styles. 2-Port Direct-Acting. Normally open valve that the ther mal system will close on rising temperature and used primarily Normally closed valve which is opened on rising temperature. For use as a cooling control, valve should contain a continu ous bypass bleed to prevent stagnate flow at sensor. for heating applications. 2-Port Reverse-Acting.

Cooling Applications: d. Cooling air compressor jacket with water

Cooling Water GPM required = 42.5 x HP per Cylinder 8.3 x ∆ T 2 Where: GPM = Gallons per minute water TR = Temperature rise of heated fluid, °F CFM = Cubic feet per minute Air ∆ T 1 = Temperature drop of heating water, °F ∆ T 2 = Temperature rise of cooling water, °F

28