3. Globe Valves and its types and applications.pptx

Globe valves and its types

1. Globe Valves Presented by: Daniyal Ahmed

2. Introduction Valves are devices that are used to direct fluid flow or regulation. They do this by obstructing passageways within them. Types of Valves: Isolation valve (Globe Valve, Gate Valve, Ball Valve, etc.) Control Valve Pressure Reducing Valve Pressure Safety Valve Globe Valve: Globe valves can be used for isolation as well as for throttling services . Because of its design, the globe valve provides a tight seal with fewer chances of leakage.

3. Working: A globe valve is primarily designed to stop, start and regulate flow. It consists of a movable disk and a stationary ring seat in a generally spherical body. The seat of a globe valve is in the middle of and parallel to the pipe, and the opening in the seat is closed off with the disk. When the handle is turned, manually or through an actuator, a disc is lowered or raised by means of the valve stem. When the disc is fully lowered, the fluid flow is shut off. When the disc is fully raised, the fluid flow is at its maximum rate. When the disc is in raised to less then maximum level, the fluid flow is regulated with proportion to the vertical travel of the disc .

4. Materials: PVC Brass ( 67% copper and 33% zinc .) Bronze ( 88% copper and 12% tin) Cast Iron (an alloy of Iron and carbon) Ductile or SG Iron (Type of Cast Iron)* Carbon Steel Stainless Steel *SG iron has spherical-shaped graphitic carbon whereas CI has flat graphitic flakes making SG iron much stronger than cast iron.

5. End Connections: Threaded or Screwed Socket Weld/Butt Weld Flanged

6. Internals of Globe Valve:

7. Globe Valve B ody Patterns: There are three primary body patterns or designs for Globe valves, namely: Standard Pattern or T – Pattern: Standard pattern globe valve body design is the most common body type. The horizontal setting of the seat allows the stem and disk to travel perpendicular to the flow direction of the fluid. Due to its tortuous flow passage, this design offers the highest resistance to flow among all of the available patterns. This design has the lowest coefficient of flow and highest pressure drop. They are used in severe throttling services, such as in bypass lines around a control valve. Standard pattern globe valves may also be used in applications where pressure drop is not a major concern and only throttling is required .

8. Globe Valves B ody Patterns: Angle pattern: Angle pattern globe valve body design is a modification of the basic standard pattern globe valve. The ends of this Globe valve are at an angle of 90 degrees, and fluid flow occurs with a single 90 degrees turn. They have a slightly lower coefficient of flow than oblique pattern globe valves. They are used in applications that have periods of pulsating flow because of their capability to handle the slugging effect of this type of flow. If the globe valve is to be mounted near a pipe bend, the angle pattern valve body offers two advantages. First, the angle pattern design has a greatly reduced flow resistance compared to the standard pattern design. Second, the angle pattern design reduces the number of pipe joints and saves a pipe elbow.

9. Globe Valves B ody Patterns: Oblique Pattern or Y – Pattern: Oblique Pattern globe valve body design is an alternative for the high pressure drop, inherent in globe valves. Oblique pattern design reduces the flow resistance of the globe valve to a minimum. Seat and stem are angled at approximately 45 degrees, what gives a straighter flow-path at full opening and offer the least resistance to flow. They can be cracked open for long periods without severe erosion. They are extensively used for throttling during seasonal or startup operations. They can be rod through to remove debris when used in drain lines that are normally closed .

10. Uses of Globe Valves: Diverting process media . Globe valves are used in the oil and gas industry for fluid regulation or throttling . Flow isolation to: Facilitate maintenance Allow the removal of equipment Allow the shutdown of the plant  Below are just a few common applications where you might find a globe valve: Cooling water systems  Fuel oil systems Feed water or chemical feed systems Boiler and main steam vents and drains Turbine lube oil system and others

11. Advantages and Disadvantages: Advantages: Good shutoff capability . Moderate to good throttling capability . Shorter stem travel between the open and closed positions as compared to a gate valve . Available in many patterns, each offering unique capabilities . Easy maintenance, as the discs and seats are readily refurbished or replaced .

12. Disadvantages: High-Pressure Drop or Head   Loss from two or more right-angle turns of flowing fluid. Large-size glove valves require considerable power to operate and are especially noisy in  high-pressure  applications . Large openings are necessary for disk assembly . Heavier weight than other valves of the same flow rating. Advantages and Disadvantages:

13. One of the most common types of Globe valve failures involves a buildup of dirt and sediment within the valve, making it difficult to open and close . Media leakage:  D amaged seals or loose nuts and bolts can cause media to leak out of the valve . Solution: Verify that your valve’s seat components are compatible with the system media. Check whether the components need to be replaced or if any hardware needs to be tightened. Failure Cases:

14. Production downtime:  A failed valve reduces production, which results in lost revenue and wasted time . Repair costs : Periodic equipment repairs are expected in any industrial setting, but repairs that result from valve failures can end up costing you more than you budgeted for. Effects of Failures:

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