Showing posts with label gate valve. Show all posts
Showing posts with label gate valve. Show all posts

Wednesday, September 19, 2018

What is an Industrial Gate Valve?

Industrial valves
Industrial valves come in a wide variety of types and styles.
 (Image courtesy of Crane)
Industrial valves are used for flow control in industrial processes at specific locations in a piping system. Valves start, stop, throttle, or divert the process fluid flow. Valve application characteristics are diverse, resulting in a broad array of possible valve choices. Valve styles and types have evolved based on their performance, safety, effectiveness, and longevity.

Valve type generally refers to the means employed to control fluid flow, specifically the body style and orifice design. These valve characteristics are used to determine whether a valve type may be suitable for your process application. The most common valve types include gate and globe valves (referred to as linear valves) and ball, plug, and butterfly valves (referred to as quarter-turn valves). All these types of valves have numerous variations and customizations occurring within each type.

The Gate Valve

Gate valve diagram
Gate valve diagram.

Gate valves utilize a movable wedge, often round or rectangular, that is positioned as to restrict the process flow path. This wedge, referred to as the gate or disc, is connected to a valve stem which extends to the exterior of the valve body. Linear motion of the stem will position the gate within the valve body to provide some degree of obstruction to the process flow path. Fully inserting the gate into the media path will shut off the flow, while successively withdrawing the gate will increase the opening through which fluid can pass and allows for increasing flow rates. Seals are provided along the planar surfaces where the gate contacts the valve body.

Gate Valve Advantages
  • When fully open, these valves provide little or no restriction to fluid flow. 
  • This valve type provides a straight through passage.
  • Gate valves can be employed bi-directionally, with flow control effectively available in both directions.
  • Installation space dimensions along the flow path are minimal.
  • Because the gate movement is perpendicular to the flow direction, the energy required to move the gate is generally low, allowing smaller actuators.
  • Closure of gate valves is comparatively slow to other types of valves, reducing the physical shock (hammering) in the piping system.
Additional Gate Valve Application Considerations
  • Valve seals are exposed to the fluid flow as the gate opens. The effects of the process media velocity and media corrosiveness on the seal material may cause deterioration at an unacceptable pace, particularly in throttling applications.
  • Gate valve stems generally extend substantially from the valve body, as they must accommodate the mounting of any required actuator and the entire range of motion of the gate. Some installations may not be able to provide the needed space for this arrangement.
  • The slower speed at which gate valves open and close may not be suitable for some applications.
  • Gate valves are generally not recommended for throttling the process flow, and using them in control applications could  result in gate vibration. There is also concern about expedited seal wear due to the exposure to higher process media velocities while throttling.

Monday, May 22, 2017

Introduction to Valve Parts or Components

cutaway view forged steel gate valve
Cutaway view of a forged steel gate valve
Courtesy Crane-ChemPharmaEnergy
Although there are many different classifications of valves specific to their respective functions, there are standard parts or components of valves you may find regardless of the classification. They are the valve body, bonnet, trim, seat, stem, actuator, and packing.

The Valve Body is the primary boundary of a pressure valve which serves as the framework for the entire valve’s assembly. The body resists fluid pressure loads from connected inlet and outlet piping; the piping is connected through threaded, bolted, or welded joints.

The Valve Bonnet is the opening of the Valve Body’s cover. Bonnets can vary in design and model, is built using the same material as the Valve Body, and is also connected to the entire assembly through threaded, bolted, or welded joints.

The Valve Trim collectively refers to all the replaceable parts in a valve, e.g. the disk, seat, stem, and sleeves––all which guide the stem as well.

The Valve Disk allows the passage or stoppage of flow. Disks provide reliable wear properties and differ in what they look like per valve type. For example, in the case of a ball valve, the disk is called a ball, whereas for a plug valve it is a plug.

The Valve Seat(s) or it’s seal rings provide surface seating for the disk. For example, a globe valve requires only one seat and this seat forms a seal with the disk to stop flow.

The Valve Stem provides the proper position which will allow the opening and closing movement of the Valve Disk. Therefore, it is connected to the Valve Disk on one end and the Valve Hand Wheel or the Valve Actuator on the other.

The Valve Yoke is the final piece in the valve’s assembly; the Yoke connects the Valve Bonnet with the actuating mechanism. The Valve Stem passes through the top of the Yoke which holds the Yoke or stem nut.

There are countless variants of valve designs, sizes, and configurations. These basic parts will be found on most, but the particular form and arrangement of the part may provide an advantage when employed for a particular application. Share your industrial process valve requirements and challenges with a valve specialist. Combine your own process knowledge and experience with their product application expertise to develop an effective solution.

Tuesday, March 21, 2017

Forged Steel Valves for the Toughest Applications

cutaway view forged steel gate valve with handle and weld socket connections
Forged Steel Gate Valve
Cutaway View
Courtesy Crane ChemPharma Energy
Forging steel produces material of greater overall strength and toughness for parts and assemblies subjected to higher levels of stress. Forging is basically accomplished by applying localized mechanical pressure across the base steel, eliminating internal voids and gas pockets, while producing a unique oriented grain structure in the metal that delivers increased fatigue resistance.

Higher pressure or temperature applications in fluid process control can benefit from, and sometimes may require, the use of forged steel valves. Their ruggedness and ability to hold up under tough conditions make forged steel valves a good choice for many uses throughout general industrial, oil and gas, and power generation installations.

Forged steel valves are available in a broad range of sizes, connection types, and port configurations. Crane, world class manufacturer of industrial valves, offers forged steel gate, globe, and check valves to provide options for flow direction, stop, and throttle control.

There are almost countless variants and configurations of industrial valves from which to choose. Share your fluid control requirements and challenges with an industrial valve expert, combining your own process knowledge and experience with their product application expertise to develop effective solutions.


Thursday, October 13, 2016

Stainless Steel Globe and Gate Valves For Industrial Process Control

stainless steel gate valve globe valve for industrial process control
Stainless Steel Gate Valve
CPE-Aloyco
Gate and globe valves see common usage throughout fluid processing industries. The correct procedure for valve selection includes an evaluation of the process media, environment, and how the valve will need to perform.

Gate valves, unless specially adapted, are intended for applications requiring only fully open or closed service. Their slow operation is advantageous at preventing hammering in the piping system and a fully open gate valve presents little pressure drop.

Globe valves are well suited for shutoff and throttling operation, controlling fluid flow at points between fully open or closed. The "Z" pattern of their fluid path does add some pressure drop.

Selecting the right valve construction material is an important element of a successful installation. Aloyco, a Crane brand, recommends consideration of several factors.
  • Type of media
  • Media temperature range
  • Pressure range, including all possible conditions
  • Environmental conditions which may affect the valve
  • Extraordinary stresses to which the valve may be subjected
  • Compliance with safety standards and/or piping codes
Stainless steel valve construction will provide an additional measure of corrosion resistance and may be a selection that extends the useful life of a valve.

More detail is included in the document included below. Share your fluid control requirements and challenges with a specialist, combining your process experience and knowledge with their product application expertise to develop effective solutions.



Wednesday, July 6, 2016

Wellhead Valves Meet Special Application Challenges

Wellhead in oil and gas industry with equipment and valves
Numerous valves are employed at oil and gas production site
Industrial valves are manufactured in a huge array of configurations to accommodate the specialized needs of a broad range of industrial process applications. The oil and gas industry is but one segment of many throughout the industrial sphere that presents its own set of application specific criteria.

Oil and gas production, essentially pulling raw material from the earth, has unique valve performance challenges. Extreme pressure and abrasive or erosive material are common elements of oil and gas production at the wellhead. The valves also need to tolerate the range of outdoor temperatures at the production site. Safe and reliable operation throughout these and a range of other conditions are part of the design criteria for these valves. Here are some of the specific valve variants and configurations applied in the oil and gas industry at the production wellhead.
swing type check valve for oil and gas production wellhead or manifold
Swing Type Check Valve
Courtesy DHV Indutries
cutaway view of slab gate valve for oil wellhead use
Cutaway view of Slab Gate Valve
Courtesy DHV Industries

  • Slab Gate Valve - Provides metal to metal seal and employs parallel gate and seal with a preloaded spring to assure positive upstream and downstream seal. Full port design allows for pigging.
  • Expanding Gate Valve - A parallel expanding gate seals positively against both seats, which are protected from the flow medium in the open and closed positions.
  • Mud Gate Valve - Designed to provide positive closure under rigorous field conditions with abrasive media. 
  • External Sleeve Adjustable Choke Valve - Designed to regulate production well flow and downstream pressure. Different trim configurations provide appropriate levels of control.
  • Needle Adjustable Choke Valve - Utilizes different trim arrangement than external sleeve type to provide good flow management, abrasion resistance, erosion resistance, and reliable service over a long life with low maintenance requirements.
  • Check Valve - Check valves of various types are utilized throughout practically all fluid flow operations, essentially anywhere that fluid is supposed to flow in only one direction. Oil and gas production presents some special conditions of abrasion, erosion, and pressure that call for special accommodation in design and materials of construction.
There are other specialty valves employed at or near the wellhead, but the key take away here is that oil and gas production generally cannot be accommodated by general purpose valves. I have included a document below that provides additional data and engineering detail for the valves touched upon in this article. Share your oil and gas production challenges with a valve specialist. The combination of your process and production experience with their product expertise will produce effective solutions.


Tuesday, February 16, 2016

Specialized Gate Valve For Control Applications

Sliding gate process control valve
Sliding Gate
Process Control Valve
Schubert & Salzer
Gate valves are widely employed throughout the industrial process control field to start and stop the flow of a wide range of fluids and slurries. The common construction of a gate valve, with a solid wedge or disc that moves perpendicularly to the direction of fluid flow, tends to limit the application of this valve type to processes where fully open or fully closed are the desired valve positions. The comparatively large travel range of the wedge from open to closed, combined with a need to close the valve slowly to avoid hammering, saddles the common gate valve with a slow operating speed. Holding the gate at a partially open position has potential to induce vibration in the fluid, resulting in noise and possible negative impact on the fluid transport system. For this reason, common gate valves are generally not used in control applications requiring flow modulation .

The limiting factors just described can be mitigated or eliminated with a modification to the gate configuration. Instead of a solid gate, two plates with matching orifice matrices are mounted in the fluid path. One plate is fixed and the other is moved by the valve actuator, sliding through a motion range that expands flow area by increasingly matching the orifice openings on the two plates. This gate valve design is often called a sliding gate valve and it is easily recognizable through its pattern of slotted openings on the gate.

Some notable features of the sliding gate valve:

  • Straight through flow path with little turbulence.
  • Flow is broken into multiple small streams by the orifice pattern, reducing the impact of the flow force on the valve trim.
  • Suitable for fluid control operation, not just fully open or closed.
  • Travel distance and time from fully open to fully closed is significantly reduced, when compared to common gate valve.
  • Quieter operation.
  • Long service life.
  • Suitable for lower viscosity, generally clean, fluids
Every valve design has applications where it will tower over others in terms of overall performance. The variable orifice control valve (sliding gate valve) will prove to be the best choice for certain applications. Share your fluid process control challenges with an industrial control specialist. Combining your process expertise with their product application knowledge is a sure way to produce positive outcomes. 


Tuesday, November 17, 2015

Mountain States Engineering and Crane Expand Their Relationship

Triple Offset Butterfly Valve
Krombach Triple Offset Metal Seated Valve
Courtesy Crane CPE


Mountain States Engineering and Controls has been selected as the new distributor of the Krombach branded valves from Crane CPE. MSEC has been a master distributor for various brands in the Crane family for fifteen years, and will be capitalizing on knowledge and experience gained from their many years of providing solutions in the industrial process control and valve fields. The Krombach branded valves complement the applications range of other industrial valves handled by MSEC.

The Krombach line includes:
  • Butterfly Valves - High performance, resilient seated, double-eccentric, triple offset and special purpose butterfly valves.
  • Ball Valves - Process one-piece, two-piece and three-piece, metal seated, soft seated and compact ball valves.
  • Globe and Angle Valves - Bronze, cast iron, cast steel and stainless steel globe and angle valves.
  • Gate Valves - Bronze, cast iron, cast steel and stainless steel gate valves.
  • Check Valves - Ball, dual-plate, foot, full body swing, steam stop, tilting disc, wafer style swing, nozzle-type and pressure seal check valves.
  • Vacuum Relief Valves - Available with flanged or threaded connections.
  • Aerating and Deaerating Valves - Essential for trouble-free operation of pipeline systems handling liquids.
  • Float Valves - Single seated and double seated versions for a variety of applications.
  • Throttle Valves - Available with flange connection, wafer- or weld-in type.
  • Bottom Drain Valves - Available manually operated or with a diaphragm actuator.
I have included below one of the many comprehensive data sheets available. More information on any application or product is available from the process control specialists at MSEC. Combining their product knowledge with your process mastery is the key to positive outcomes.

Monday, June 22, 2015

Selecting the Right Valve Type - Gate Valves

There are many types of valves available for industrial fluid handling and process control applications. Specifying the proper valve type for an application can be made easier with some basic knowledge about the application strengths and weaknesses of the various valve types.

gate valve cutaway view
Gate Valve Cutaway View
Courtesy DHV Industries
Gate valves open and close by changing the position of a rectangular or round wedge (the gate) in the fluid flow path. The sealing surfaces are arranged in a planar fashion and the gate, which is commonly either flat or wedge shaped, slides along the sealing surface from the open to closed position. Because of the cross-sectional shape of pipes, which is often mimicked in the valve body, the size of the opening created as the gate valve opens and closes does not change at the same rate as the percentage of total available movement of the gate. This non-linear aspect of valve operation can make a gate valve less suitable for an application where flow rate must be accurately controlled across the range from fully open to fully closed. Complicating throttling operations further is the possibility of the gate vibrating when partially open, due to the fluid flow around the gate assembly. Unless specifically designed for throttling, gate valves are generally best suited for applications requiring either full flow or no flow. Because of its operating nature and construction, a gate valve may prove to be the appropriate selection, based upon the type of media or fluid which is being controlled.

In addition to specifying the manner in which the valve will be connected within the piping system, consideration should be given to construction of the valve body. If it may be necessary to inspect, service, or clean the valve interior, look for a bonnet connection that will permit suitable access to the valve interior.

Once you have decided that a gate valve will be the most suitable type for your application, there are many other considerations in valve selection. Draw on the experience and knowledge of coworkers, maintenance technicians, and valve sales engineers to help specify a valve assembly that meets the needs of all project stakeholders.