Presentation is loading. Please wait.

Presentation is loading. Please wait.

Control Valves: Specifications, Sizing & Technologies.

Similar presentations


Presentation on theme: "Control Valves: Specifications, Sizing & Technologies."— Presentation transcript:

1 Control Valves: Specifications, Sizing & Technologies

2 David Kandel Application Consultant Belimo David Kandel Application Consultant Belimo

3 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

4 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

5 Understating Coil Behavior Coil Performance Coil Power / Flow Flow / Control Signal BTUh Valve GPM Resulting Coil Output ΔTΔT

6 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

7 Valve Specs Pressure/Temperature Ratings Body Pressure Close-Off Pressure Close-Off Leakage DP Temp Ratings Valve Flow Characterization Curve Rangeability/Turndown Valve Authority Actuation Fail Safe Normally Open/Normally Closed

8 Body Pressure Pressure Vessel Burst Rating Measured in psi Failure Threshold of the Vessel

9 Body Pressure ANSI Body Rating Relationship between Pressure and Temperature

10 Close-Off Pressure The maximum pressure that a valve can withstand without leakage while in the fully closed position. P1P1

11 Close-Off Pressure Rule of Thumb 2-way Valve Close-off pressure should at least equal the maximum pressure produced by the circulating pump 3-way Valve Close-off pressure should at least equal the system differential pressure

12 Close-Off Pressure Close-Off Leakage Bubble Tight is not an ANSI rating. Bubble Tight implies No water leakage.

13 Pressure Drop P1P1 P2P2 The maximum allowable pressure differential that a fully open valve can withstand without damaging the internals of the valve.

14 Temperature Ratings Media Temperature (hydronic) Acceptable fluid temperature range Media Temperature (steam) Commonly measured in lbs of steam Ambient Temperature Usually an actuator rating

15 Characterization Curves Equal Percentage Linear Quick Opening Modified Equal Percentage Valve Position Flow Modulating Control of a Coil CCV, PI-Valves, Globe Valve Modulating Control of Steam Coil or Bypass Applications ePIV, Globe Valves 2 Position control Zone Valves Varies based on design Butterfly Valves, others

16 Rangeability & Turndown Rangeability: The ratio of maximum flow to minimum controllable flow of a valve body only under laboratory conditions with a constant differential pressure applied across the valve. Turndown Ratio: The ratio of maximum usable flow to minimum controllable flow of the valve assembly under installed conditions. It is always lower than the rangeability factor.

17 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

18 Flow Coefficient FLOW COEFFICIENT (Cv) is the quantity of water in gpm at 60 DegF that flows through an open valve with a pressure drop of 1psi.

19 Hydronic Valve Sizing Example: Coil Requires 8 GPM Design DP for valve, 4 psi DP of Valve not to exceed 5 psi

20 Hydronic Valve Sizing Example: Coil Requires 8 GPM Design DP for valve, 4 psi DP of Valve not to exceed 5 psi

21 Hydronic Valve Sizing Checking DP Example: Coil Requires 8 GPM Design DP for valve, 4 psi DP of Valve not to exceed 5 psi

22 Hydronic Valve Sizing Checking DP

23 Hydronic Valve Sizing Checking DP Which should we select? And Why? Which should we select? And Why?

24 24 Valve Authority Coil Balance Valve Valve Opening (%) Flow (%)

25 Coil Balance Valve Valve Authority

26 Valve Opening (%) Flow (%) 26 Valve Authority Valve Opening (%) Valve Authority Distortion Flow / Coil Output (%)

27 Hydronic Valve Sizing Differential Pressure Across the Valve Should be greater than coil DP Valve Authority > 0.4 Typically between 3psi - 5psi for modulating Typically about 1 psi for on/off Rules of Thumb

28 Pipe Reduction Factor ½" valve in a ½" pipe with a Cv tested at 10 Same ½" valve in a 1" pipe will test at Cv = 6.3

29 Pipe Reduction Factor

30 Only for Valves with High Cv relative to line size

31 Pipe Reduction Factor Choosing Valves Smaller than Line size The control valve shall be no less than ½ the pipe size… However, it’s best to keep the valve size reduction no greater than 2 pipe sizes. Large pipe reductions can increase the effects of cavitation Rules of Thumb

32 Piping Considerations Which is Correct? And Why is it Correct? day month yearTemplate 32

33 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

34 Cv = Flow Coefficient Q = lbs per hour of steam ΔP = Differential Pressure in psig Po = Outlet Pressure in psia (psia = psig ) ΔP = 80% inlet gauge pressure (psig) Steam Valve Sizing Low Pressure Steam (under 15psi)

35 Example: Size a modulating control valve for 160 lb/hr with a 5 psig steam supply. Steam Valve Sizing Low Pressure Steam (under 15psi)

36 Steam Valve Sizing Cv = Flow Coefficient Q = lbs per hour of steam ΔP = Differential Pressure in psia Po = Outlet Pressure in psia (psia = psig ) ΔP = 42% absolute inlet pressure (psia) More than 15psi

37 Example: Size modulating 1/3-2/3 valves for a heat exchanger with a design flow of 600 lb/hr at 30 psig. Steam Valve Sizing More than 15psi

38 1/3 rd : 2/3 rd : Example: Size modulating 1/3-2/3 valves for a heat exchanger with a design flow of 600 lb/hr at 30 psig. Steam Valve Sizing More than 15psi

39 1/3-2/3 Valve Sequencing

40 Agenda Control Valves: Specification, Sizing and Technologies Controlling a Coil Ratings and Definitions Hydronic Valve Sizing Steam Valve Sizing Control Valve Technology © Belimo, 2012

41 Control Valve Technologies

42 Characterized Control Valves Ball Valve (rotary action) Characterizing Disc CCV

43

44 2-way

45 CCV 3-way (Mixing or Diverting)

46 CCV Pros Inexpensive Equal Percentage Characteristic High Close Off Large Range of Cv Cons Hot and Chilled Water with Glycol Only Applications Hot & chilled water coils (for air handling units) Unit ventilators Fan coils VAV units Valve Summary

47 Globe Valves Linear Action Plug Design

48 Globe Valves Close-Off Rating Determined by Force Applied to Stem Close-Off is Actuator Dependent Close-Off Pressure Pu Pd

49 Globe Valves 3-way Mixing

50 Globe Valves 3-way Mixing

51 Globe Valves 3-way Diverting

52 Globe Valves 3-way Diverting

53 Globe Valves Pros Equal Percentage or Linear Characteristic SS Trim works for Steam Cons Expensive Large 2 Versions of 3-way Close off depends on Actuator Applications Hot & chilled water coils (for air handling units) Chillers Valve Summary

54 Pu Pd Holes in Plate Balance the Pressure What is a Pressure Compensated Globe Valve? Globe Valves

55 Standard Globe Valve Close-Off Ratings AFX24-MFT2xAFX24-MFT G6652½”51 psi G6652½”82 psi G6803”34 psi G6803”56 psi Pressure Compensated Close-Off Pressures Pressure Compensated GV Close-Off Ratings AFX24-MFT2xAFX24-MFT G665C2½”150 psi G680C3”150 psi G6100C4”150 psi G6125C5”150 psi G6150C6”105 psi

56 Butterfly Valves Rotary Action Flow Characteristic: Modified Equal Percentage Rotating Disc and Resilient Seat

57 Butterfly Valves

58 3-Way Butterfly Valves 2 Valves linked on a Tee Mixing or Diverting 1 or 2 Actuators

59 Butterfly Valves 3-Way Butterfly Valves 2 Valves linked on a Tee Mixing or Diverting 1 or 2 Actuators

60 Butterfly Valves 12 ft/sec in Standard BFV 32 ft/sec in High Performance BFV Sizing a BFV: Velocity

61 Butterfly Valves Pros Up to 30” Inexpensive High Close-Off SS and HP Available Cons Modified Eq % High Cv Relative to Size Velocity Limitations Applications Chiller and Cooling Tower Isolation Change Over Systems Large Air Handlers Bypass Controls Valve Summary

62 V-Ball Valves For Extreme Conditions 400F Water 250 PSI Steam 150 PSI Close-off Controls Equal Percent Flow Characteristic 300:1 Rangeability V-Ball (Segmented Ball Valve)

63 V-Ball Valves Rotatory Valve Single seat Partial Ball reduced torque requirement V-Ball (Segmented Ball Valve)

64 Pros For extreme applications High Temp Water High Pressure Steam High rangeability Cons Expensive Limited sizes and Cv Large (heavy) Applications Hot & chilled water coils (for air handling units) Chillers Valve Summary

65 Zone Valves Inexpensive 2 Position Spring Return “Paddle” Design Zone Valves

66 2-Way 3-Way Diverting

67 Zone Valves Pros Cheap Fail Safe Cons Cheap 2 Position Only Low Close-Off Applications Baseboards Low Flow needing 2 position, fail safe Valve Summary

68 Pressure Independent Valves Pressure Independent Control Valves 2-way valve that supplies a specific flow for each value of the control signal – – Regardless of pressure variations in the system PI Valve Pressure Flow

69 Pressure Independent Mechanical RegulatorElectronic Flow Meter Technologies

70 Pressure Independent Valves Pros Accurate Flow Regardless of Pressure Conditions Increased Water-side DT Reduced Pump Energy Usage Valve Authority = 1.0 Eliminates need of Automatic Balancing Valves Cons Higher Initial Cost Applications Hot & chilled water coils (for air handling units) Unit ventilators Fan coils VAV units Valve Summary

71 Control Valves: Specifications, Sizing & Technologies Questions?


Download ppt "Control Valves: Specifications, Sizing & Technologies."

Similar presentations


Ads by Google