Friday, November 16, 2018

What is a Triple Offset Valve (TOV)?

Triple Offset Valve
Click for larger view.
As the name implies, there are three separate offsets designed into the triple offset valve. Two of the offsets apply to the location of the shaft with respect to the center line of the bore and the center line of the disc/seat sealing surfaces.

The third offset in the design is the axis of the seat cone angle that is inclined from the center line of the valve bore. This eliminates rubbing of the seat/seal contact surfaces during operation and preserves sealing integrity over the cycle life of the valve.

The contact is made in only the final point of closure, acting as a mechanical travel stop which prohibits over-travel of the disc.

Applications and Method of Control

A triple eccentric or triple offset butterfly valve should be used when the application requires bubble tight shut-off, but does not allow the use of a rubber-lined butterfly valve due to low/high temperatures and high pressure. The triple offset design can be used for on/off services, throttling services and modulating services.

On/Off Service
Like the name suggests, on/off valves are designed to shutoff and to open fully but lack the ability to to regulate effectively through the range of travel.

Throttling Service
Throttling service (sometimes referred to as inching) is in general flow control through the system where the valve is set and held in an intermediate position.

Modulating Service
Modulating service (known also as regulating service) is used to drive the valve frequently to any position between fully open and fully closed to control the flow. It uses feedback from the field, and valve disc position is adjusted almost continuously.

Quarter turn valves are usually limited to a throttling range of ~25° to ~75° open (25% to 85%). In case of throttling the manufacturer should be consulted in order to predict whether the control valve was installed accurately.

For more information, contact Mountain States Engineering and Controls. Visit their web site at https://mnteng.com or call 303-232-4100

Monday, October 29, 2018

Level Controls Used on Grain Silos and Hoppers

Here is a short video displaying NIVELCO level instruments being used on grain silos and hoppers.

NIVELCO manufactures level measurement and control transmitters using microwave, guided wave radar, ultrasonic, capacitive, and magnetostrictive technologies as well as level switches utilizing float, conductive, magnetic, and vibrating technologies.


For more information, contact:
Mountain States Engineering and Controls
1520 Iris Street
Lakewood, CO 80215
303-232-4100 Phone
303-232-4900 Fax
www.mnteng.com

Monday, October 22, 2018

Emerson/Kunkle Pressure Relief Valves: Operating and Safety Instructions

Kunkle Pressure Relief Valve
Emerson/Kunkle Pressure Relief Valve
Before installation these instructions must be fully read and understood.

PRE-INSTALLATION HANDLING

This pressure relief valve is designed to protect equipment from overpressure. The valve should be handled with care, not subjected to heavy shock loads, and protected to prevent dirt from getting inside. It should be installed correctly. Failure to do so could result in property damage or serious injury to personnel. When hoisting the valve into position for installation, care should be exercised so that lifting straps do not contact the valve lift lever. service life may vary upon condition of service. Check unit at least once per 8000 hours or longer intervals based upon site experience.

INSTALLATION
  1. Mount the valve in a vertical position so that the valve body is self draining. If a body drain port is provided, make sure it is open when required by the ASME code. Do not plug any bonnet vent openings. The inlet piping should be as short as possible, with no elbows, and equal to or greater than the size of the pressure relief valve inlet connection. This will help to limit the inlet pressure drop to 3% or less when the valve is relieving.
  2. When discharge piping is connected to valve outlet, make sure it is self draining if a body drain port is not used. The valve should not be connected to any discharge pipe that contains pressure before the valve opens or to any pipe where the pressure build-up is greater than 10% of the set pressure when the valve is open and relieving.
    Discharge piping, other than a short tailpipe, must be supported. For steam service, a drip pan elbow or flexible connection between the valve and the pipe should be used to prevent excessive pipe stress, due to thermal expansion, from being imposed on the valve body.
  3. For threaded valves, to prevent sealing compound from entering and damaging the valve, apply a small amount of pipe thread sealing compound to external threads only. Do not put any sealing compound on the first thread or on any internal threads. To do so may cause the sealing compound to enter the valve and cause seat leakage. Do not use the valve body or bonnet for installing the valve in threaded connections. Use the wrench flats provided to tighten the valve to the connecting pipe, and do not over-tighten. To do so may cause valve leakage.
  4. For flanged valves, use new gaskets and tighten the mounting studs evenly.
OPERATION
  1. Maintain a system operating pressure at least 5 psig or 10% below the set pressure of the valve, whichever is greater.  Operating too close to the valve set pressure will cause seat leakage and will shorten the time between valve maintenance.
  2. Do not use the safety valve as a control valve to regulate system operating pressure. Excessive operation will cause the seat to leak and will require more frequent valve maintenance.
  3. ASME Section I and VIII valves equipped with lift levers are designed to be operated only when the system pressure is 75% of set pressure or greater. ASME Section IV valves may be operated at any set pressure. When hand operating the valve, hold it open long enough to purge any foreign matter from the seat area. If a cable or wire is attached to the lift lever for remote actuation, make sure the direction of pull is the same as it would be if the lever were pulled directly by hand.
MAINTENANCE

Maintenance should be performed on a regular basis. An initial inspection interval of 12 months is recommended. Depending on the service conditions and the condition of the valve, the inspection interval may be decreased or increased. Use only Kunkle parts for repair. Depending o the local jurisdictional requirements where the valve is installed, repairs may have to be made by a repair facility holding a VR stamp.

WARNING

Removal of the seal wire or any attempt to adjust, repair, or modify this product by non-qualified or non-authorized persons voids the product guarantee and may cause serious damage to equipment, personal injury, and death. Kunkle Valve is not liable for any damages resulting from misuse or misapplication of its products.

Sunday, September 30, 2018

Mountain States Engineering & Controls


Since 1978, Mountain States Engineering & Controls has served the industrial markets of Colorado, New Mexico, Wyoming, Montana, Utah, Nevada, Idaho, and the western Dakotas.  MSEC is a Manufacturer's Representative & Distributor of process equipment and controls headquartered in Lakewood, Colorado.

We support customers with application, design, and product start-up assistance as well as after-the-sale service and training. It is our absolute goal to ensure that our products and services exceed your expectations.

Mountain States Engineering & Controls represents some of the most recognized and innovative manufacturers in the market today, and carries high quality products designed to meet our customer's most demanding applications. MSEC products solve challenging problems for industrial and commercial applications in the power, chemical, mining, energy, water treatment, and manufacturing industries as well as in universities, hospitals, and government  facilities.

Mountain States Engineering & Controls has on-staff experts ready to assist you in selecting the right product for your application. As we have been for over 40 years, we're there when you need us.

https://mnteng.com
303-232-4100

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.

Friday, August 31, 2018

What is a Cooling Tower?

An evaporative cooling tower is heat removal device that uses ordinary water to transfer process waste heat from building and equipment into the atmosphere. All cooling towers operate on the principle of removing heat from water by evaporating a small portion of water that is recirculated through the unit.

The mixing of warm water and cooler air releases latent heat of vaporization, causing a cooling effect to the water.  Cooling towers are a key component of many refrigeration systems and can be found in industries such as chemical processing plants, power plants, steel mills, food processing plants, and many other manufacturing companies where process cooling is required.  Cooling towers are also used to provide comfort cooling for large commercial buildings such as universities, government facilities, airports, schools, hospitals, and hotels.

The video below provides a short review of what cooling towers are and why they are important.

Tuesday, August 14, 2018

Industrial Control Valve Basics

Understanding industrial control valve design and operation is very important if you work as a process engineer, a plant maintenance person, or if you design process control loops. Control valves are used extensively in power plants, pulp and paper mills, chemical manufacturing, petro-chemical processing, mining facilities, HVAC and steam distribution systems.

There are many types, manufacturers, body styles, and specialized features, but the they all share some basics operating principles. The video below explains components, operation, and fundamentals of how control valves operate.

https://mnteng.com
303-232-4100