Basics of Industrial Globe Valves

Exploded view of globe valve
(courtesy of Conval)
Globe valves work differently when compared to gate valves, ball valves, butterfly valves and plug valves in process control applications. They are primarily used to control the flow inside pipes, and are popular in a wide variety of industries. Globe control valves are ideal in situations where precise control is required. They are used to regulate flow in pipelines with a high degree of accuracy by regulating a pressures drop created in the valve body that allows the fluid to pass through the passageway (port) in the valve body. The control valve stem provides linear motion to control flow, opening and closing the valve by changing the distance between valve disc and seat. The flow in the pipeline changes according to the position of the disc lifting from the seat. The movement is controlled through the use of manual operators, or through the use of electric or pneumatic actuators.

Applications of Globe Valves

Globe valves are used in many different industries, but particularly in the petrochemical and power generation industries on fuel oil pipes, chemical feed systems, steam pipes, as well as cooling water and feedwater systems.  Other industrial applications of globe valve include boiler, main steam vents, and turbine lube oil systems.

Pros

Globe valves have many advantages that make them preferable over other valve designs. Globe control valves have excellent shut-off and throttling capabilities. In addition, globe valves are easy to maintain and repair compared to other valves.

Cons

Internal view of globe valve
(Conval)
Globe valves have also certain shortcomings. For instance, globe valves have an S-shaped flow pattern (as opposed to a straight-through flow pattern) which creates a significant pressure drop making them unsuitable for applications constant pressure is required.  Another shortcoming of the globe valves is they generally require greater torque to open and close, requiring larger actuators to properly seat the valve.

For more information on industrial globe valves, or any type of industrial valve, contact Piping Specialties, Inc. by calling 800-223-1468 or by visiting https://psi-team.com.

MOGAS Critical Service Valves Fire Tested to API 607 and API 6F3


This video explains the MOGAS approach to fire testing their severe service ball valves to API requirements.
  • API 607, 7th Ed. Fire Test for Quarter-turn Valves and Valves Equipped with Nonmetallic Seats
  • API 6FA, 3rd Ed. Specification for Fire Test for Valves
Piping Specialties, Inc.
800-223-1468

Hyspan Series 1500 Laminated Bellows Expansion Joints

Pipe expansion or contraction resulting from temperature changes is independent of line size; however, the bellows elements of small diameter expansion joints have less ability to absorb motion than larger sizes because of restrictions on the corrugation size. Recognizing these shortcomings, Hyspan® developed Series 1500 Laminated Bellows Expansion Joints for applications that involve axial motion.

The bellows elements are designed with up to four individual thicknesses or laminations of precision stainless steel foil. This design procedure combines the high flexibility of thin material while providing the pressure resistance of multiple laminations. 

As a comparison, a bellows made from four plies of 0.008" thick material has the same pressure rating as a single thickness of0.016" thick, but the laminated construction will deflect twice as much and requires only one-half the force to compress.


Piping Specialties, Inc.
https://psi-team.com
800-223-1468

The Pratt Industrial TE Series Triple Offset Butterfly Valve

The Triple Offset Butterfly valve has been designed to answer the industries demand for an alternate solution to gate valves and ball valves where weight, space,  performance, and the ability to modulate to the process flow were an issue.

Pratt Industrial Triple Offset Butterfly Valves are from the family of quarter-turn valves. This valve is designed and manufactured to meet API 609 and ASME B16.34 specifications.

Applications
  • Block/Isolation
  • Modulating; manual, pneumatic, or electric motor operators.
Industries
  • Refinery
  • Chemical
  • Petrochemical
  • Power
  • Steam Generation
  • Water/Waste Water Treatment


What Are LINK-SEALS?

Considered to be the premier method for permanently sealing pipes of any size passing through walls, floors and ceilings, LINK-SEALS® are a modular, elastomer sealing system that creates a permanent, hydrostatic seal for nearly any cylindrical object as it passes through a barrier. With LINK-SEALS®, any cylindrical object may be quickly, easily and permanently sealed against the entry of water, soil or backfill material.

Why You Should Use LINK-SEALS®:
    LINK-SEALS
  • Install in up to 75% less time compared to lead-oakum joints, hand-fitted flashings, mastics, or casing boots.
  • Designed for use as a permanent seal. Seal elements are specially compounded to resist aging and attack from ozone, sunlight, water, and a wide range of chemicals.
  • Rated at 20 psig (40ft of head), which exceeds the performance requirements of most applications.
  • NSF 61 and Factory Mutual Fire Approved materials available. Also carry a wide variety of approvals from various Federal agencies, associations, code groups, laboratories, and organizations.
  • Standard fasteners have a two-part zinc dichromate and proprietary corrosion inhibiting
    LINK-SEALS
    coating. Corrosion resistant 316 stainless steel available for maximum corrosion protection.
  • Manufactured in an ISO 9001certified facility.
  • 16 sizes, color-coded EPDM, Nitrile, and Silicone elastomers may be used with various hardware options to match performance characteristics with service conditions.

For more information about LINK-SEALS®, contact Piping Specialties, Inc.
https://psi-team.com
800-223-1468

Jet Pump (Eductor) Theory of Operation

Jet Pump (Eductor)
Jet Pump (courtesy of Emerson Penberthy)
Also known as eductors, jet pumps operate on the principles of fluid dynamics. An operating fluid medium, which is referred to as the MOTIVE, placed under pressure, enters the inlet and is forced through the nozzle where it is converted into a high-velocity stream. This high-velocity stream decreases the pressure in the suction chamber, creating a partial vacuum that draws the suction material into the chamber where it is entrained by the motive medium. Once the SUCTION stream is drawn in, shear between the motive medium and the transported material causes both media to be intermixed and pumped out the DISCHARGE outlet, dispelled at a pressure greater than that of the SUCTION stream but lower than that of the MOTIVE. This basic principle of fluid dynamics is what makes jet pumps work.

MOTIVE:

This function is the power phase of the pumping operation. At this stage, the velocity of the motive medium increases as it passes through a nozzle. This phase of the pumping operation takes advantage of the kinetic properties of the motive medium, whether it is liquid, steam or gas. Because of this, design differences may exist within the motive connection of the jet pump.

For instance, jet pumps with liquid motives use a converging nozzle, since liquids usually cannot be compressed. On the other hand, jet pumps with gas or steam motives use converging/ diverging nozzles to achieve transsonic flow velocity. The critical flow paths of all jet pumps are machined smoothly with no abrupt turns or steps in order to produce the most efficient flow during the motive function. Without this direct flow design and smooth interior surface, the jet pump would not operate at peak efficiency.
Jet Pump (Eductor) Theory of Operation
Click for larger view.
This connection is where the pumping action takes place. The high velocity stream of the motive causes a drop in pressure in the suction chamber. This allows pressure in the suction vessel to push a liquid, steam or gas into the suction chamber of the jet pump. This, in turn, is entrained by the high-velocity motive stream emerging from the inlet nozzle.

DISCHARGE:

As the motive flow combines with the suction medium, some kinetic energy of the motive is transferred to the suction, mixing and discharging at a reduced pressure. The amount of pressure that can be recovered depends on the ratio of motive flow to suction flow, plus the amount of suction pressure built up in the suction vessel. Kinetic energy is converted back to pressure as the mixed media passes through the diverging taper and is discharged from the pump.

For more information about jet pumps and their applications, contact Piping Specialties, Inc. by calling 800-223-1468 or by visiting their web site at https://psi-team.com.

Direct Acting and Pilot Operated Pressure Relief Valve Operation


relief valve
Here is a clear and well illustrated tutorial video demonstrating the operational principals of pilot and direct acting pressure relief valves.

There are many available configurations of pressure relief and safety valves, each tailored to accommodate a particular set of application criteria. Understanding how these valves work is important to their proper selection and application to industrial processes and their control.

Safety mindedness is critical for these applications, and you should always talk to an experienced applications expert before specifying or installing these products. Product performance and selection information, as well as application assistance, is available from your local product specialists.

Piping Specialties, Inc.
https://psi-team.com
800-223-1468