Friday, November 15, 2019

Understanding the Various Kinds of Steam Traps

Steam Trap

It is essential, without loss of live steam, to remove condensate and often air and other incondensable gases from steam systems. Knowing the range of steam traps allows the best choice to be made for all applications. 

Thermodynamic steam traps

Thermodynamic steam traps combine reliability, simplicity and efficiency of operation; with just one moving part (a hardened stainless steel disc) they give a blast discharge with clean, tight shut-off. They are able to withstand: superheat, water hammer, corrosive condensate, freezing and vibration. 

Ball float steam traps

Ball float steam traps are extremely versatile and work efficiently on both light and heavy condensate loads. Although compact in size, their discharge capacity is high and continuous, ensuring maximum heat transfer. These traps are the best choice for draining plant with automatic temperature control.
An integral air vent is fitted as standard and an adjustable needle valve is available as an option to prevent steam locking.

Balanced pressure thermostatic steam traps

Balanced pressure thermostatic steam traps adjust automatically to varying steam pressures and have excellent air venting characteristics during plant start-up and during normal operation. They have large discharge capacities for their size and the robust design of the internals gives a good life expectancy.

Sealed steam traps

Sealed maintenance free steam traps.
Range: balanced pressure, inverted bucket and bimetallic versions.

Inverted bucket steam traps

Inverted bucket traps are the most robust type of the mechanical traps and will resist water hammer. When the check valve option has been fitted in the inlet, they can be used with superheated steam. They are available with a wide selection of valve orifices for precise pressure and load matching.

Bimetallic thermostatic steam traps

Bimetallic steam traps can conserve energy by discharging sub-cooled condensate in those applications which can utilize sensible heat. They are the most robust of all the thermostatic steam traps, being able to withstand water hammer and corrosive condensate.

For more on steam traps and condensate recovery, or for other Spirax Sarco products, contact Mountain States Engineering and Controls. Call them at 303-232-4100 or visit their web site at https://mnteng.com.

Sunday, September 29, 2019

Valve Actuator Basics

Valve actuators are categorized based upon a number of factors including power source available,  torque necessary to operate the valve, installation location,  and the need for automatic actuation.  Actuators are devices which supply the force and motion to open and close valves. They can be manually, pneumatically, hydraulically, or electrically operated. In common industrial usage, the term actuator generally refers to a device which employs a non-human power source and can respond to a controlling signal.

Types of actuators include:
  • Electrical motor
  • Pneumatic
  • Hydraulic
  • Manual handwheel or lever

Electric Actuators
Electric Actuator
Electric Actuator

Electric motors permit manual, semi-automatic, and automatic operation of the valve. Motors are used mostly for open-close functions, although they are adaptable to positioning the valve to any point opening. The motor is usually a, reversible, high speed type connected through a gear train to reduce the motor speed and thereby increase the torque at the stem. Direction of motor rotation determines direction of disk motion. The electrical actuation can be semi-automatic, as when the motor is started by a control system. A handwheel, which can be engaged to the gear train, provides for manual operating of the valve. Limit switches are normally provided to stop the motor automatically at full open and full closed valve positions. Limit switches are operated either physically by position of the valve or torsionally by torque of the motor.

Pneumatic Actuator
Pneumatic Actuator

Pneumatic Actuators

Pneumatic actuators are used for automatic or semi-automatic valve operation. These actuators translate an air signal into valve stem motion by air pressure acting on a diaphragm or piston connected to the stem. Pneumatic actuators are used in throttle valves for open-close positioning where fast action is required. When air pressure closes the valve and spring action opens the valve, the actuator is termed direct-acting. When air pressure opens the valve and spring action closes the valve, the actuator is termed reverse-acting. Duplex actuators have air supplied to both sides of the diaphragm. The differential pressure across the diaphragm positions the valve stem. Automatic operation is provided when the air signals are automatically controlled by circuitry. Semi-automatic operation is provided by manual switches in the circuitry to the air control valves.

Hydraulic Actuators

Hydraulic Actuator
Hydraulic Actuator
Hydraulic actuators provide for semi-automatic or automatic positioning of the valve, similar to the pneumatic actuators. These actuators use a piston to convert a signal pressure into valve stem motion. Hydraulic fluid is fed to either side of the piston while the other side is drained or bled. Water or oil is used as the hydraulic fluid. Solenoid valves are typically used for automatic control of the hydraulic fluid to direct either opening or closing of the valve. Manual valves can also be used for controlling the hydraulic fluid; thus providing semi-automatic operation.

Manual Actuators
Manual Actuator
Manual Operator

Manual actuators are capable of placing the valve in any position but do not permit automatic operation. The most common type mechanical actuator is the handwheel. This type includes handwheels fixed to the stem, hammer handwheels, and handwheels connected to the stem through gears.

Gear Operators

If additional mechanical advantage is necessary for a manually-operated valve, the valve bonnet is fitted with manually-operated gear heads as illustrated in Figure 32. A special wrench or handwheel attached to the pinion shaft permits one individual to operate the valve when two individuals might be needed without the gear advantage. Because several turns of the pinion are necessary to produce one turn of the valve stem, the operating time of large valves is exceptionally long. The use of portable air motors connected to the pinion shaft decreases the valve operating time.

For more information about industrial valves and valve automation, contact Mountain States Engineering and Controls by calling 303-232-4100 or visit their web site at https://mnteng.com.

Friday, September 13, 2019

Spirax Sarco Steam Trap Handbook

Download the Steam Trap Handbook Here
Removing condensate and air from your system is essential. Returning condensate to the boiler house maximizes use of energy. Spirax Sarco the right steam trap for your application and Mountain States Engineering and Controls has the right people to advise you. Products include:

BALANCED PRESSURE STEAM TRAPS

Balanced pressure thermostatic steam traps adjust automatically to varying steam pressures.

BIMETALLIC STEAM TRAPS

Bimetallic steam traps can conserve energy by discharging sub-cooled condensate in those applications which utilize sensible heat.

FAULT DETECTION

Our solutions for effective steam trap management.

FLOAT AND THERMOSTATIC STEAM TRAPS

Extremely versatile traps that work efficiently on both light and heavy condensate loads.

INVERTED BUCKET STEAM TRAPS

Inverted bucket traps are the most robust type of the mechanical traps.

LIQUID EXPANSION STEAM TRAPS

The liquid expansion steam trap employs a liquid expansion device to discharge condensate at a predefined temperature.

MANIFOLDS

The modern method of manifolding is to purchase the manifold as a standard piece of equipment just like buying a steam trap.

SEALED STEAM TRAPS

Replacement sealed traps utilize a non-remakeable joint, eliminating the risk of leaks to atmosphere.

SWIVEL CONNECTORS AND TRAPS

Our range of connectors significantly reduce installation time, cuts costs dramatically, and eliminate system leaks.

THERMODYNAMIC STEAM TRAPS

Thermodynamic steam traps combine reliability, simplicity and efficiency of operation.

For more information, contact:
Mountain States Engineering and Controls
600 Corporate Circle, Suite F
Golden, CO 80401
303.232.4100 Phone
303.232.4900 Fax
https://mnteng.com

Tuesday, August 27, 2019

An Introduction to VSI Controls: Process Control Valves


VSI Controls, a wholly-owned subsidiary of PetrolValves, offers customers general and severe service rotary and reciprocating control valve systems that provide a best-fit solution for their processes.

VSI Controls' valve offering includes Reciprocating Globe, Angle and Three-Way, Rotary Eccentric Plug, Double and Triple Offset Butterfly, Segmented V-Ball, Specialty Ball, Desuperheaters and Regulators. All are provided with Double-acting spring return actuators and advanced digital positioners and provide the thrust, speed, accuracy and response to handle the most exacting applications.

The video above introduces the viewer to the various VSI Controls control valve models.

Mountain States Engineering and Controls is a proud VSI Controls sales channel partner and can assist you with your control valve application in the states of Colorado, New Mexico, Wyoming, Montana, Utah, Nevada, Idaho, Western North Dakota, and Western South Dakota.

Mountain States Engineering and Controls
600 Corporate Circle, Suite F
Golden, CO 80401
303.232.4100 Phone
303.232.4900 Fax
https://mnteng.com

Tuesday, August 13, 2019

Basic Control Theory Tutorial

Basic control theoryThis basic control theory tutorial looks at on/off and continuous control modes. It introduces proportional, integral and derivative control actions and explains some of the terminology. Courtesy of Spirax Sarco and Mountain States Engineering and Controls.

Topics Include:
  • On/off control
  • Continuous control
  • Proportional control
  • The effect of adjusting the Proportional-band
  • Reverse or direct acting control signal
  • Gain line offset or proportional effect
  • Manual reset
  • Overshoot and ‘wind up’
  • Derivative control - rate action
  • PID controllers
  • Hunting
  • Lag
  • Rangeability
  • Turndown ratio


Monday, July 22, 2019

Introduction to Gas Pipeline Block Station Valves

Gas Pipeline

When a gas pipeline is constructed it is divided up into segments using block valve stations. This enables various sections to be isolated for inspection and maintenance. The block valve is typically a full-bore, soft seated ball valve to allow for "pigging", a practice that includes cleaning and inspecting the pipeline. However, it is not recommended that soft seated ball valves be opened against full differential pressure as damage to the valve seats can occur. To mitigate valve seat damage, a bypass system is installed around the main block valve to balance the pipeline pressure prior to opening. For these bypass requirements, plug valves are commonly used because their inherent design tolerates full differential pressure and allows for the opening and throttling without damage.

Why You Need a Bypass 

Full port ball valve
Full port ball valve
For any given section of pipeline, the block station valve opening process begins after completion of inspection and/or maintenance has been completed and this section is now ready to be returned to service. 

Because the block valve (often is a soft seated ball valve) is exposed to full differential pressure, it faces a huge pressure drop across the valve as it opens. The pressure drop generates high velocity flow, very often accompanied by scale, rust and dirt particles. These particles come in contact with the valve seats resulting in seat erosion and damage. Once the valve seats are damaged, the block valve cannot seal bubble tight once closed. To avoid the block valve seats from being exposed to high velocity, erosive particles, a bypass is utilized to balance the pressure either side of the block valve prior to the opening of the block valve.

Prevention of Block Valve Seat Deterioration Using Bypass Valves

plug valve
Plug valve (CRANE Xomox)
A typical bypass system includes two (2) bypass valves and One (1) vent valve. With the vent valve closed, the first of two bypass valves (Bypass Valve 1) is opened allowing pressure into the bypass piping. Usually, a plug valve is be used because it can tolerate full differential pressure without seat damage. Next, bypass the second bypass valve (Bypass Valve 2) is slowly opened, gradually building pressure in the downstream section of the pipeline until the pressure either side of the main block valve is equalized. Plug valves are also commonly used here because they are capable of controlling the flow without seat damaged.

With the pressure now equalized in the pipeline, the block valve can be opened safely, without the risk of seat damage. Bypass valves 1 & 2 have done their jobs and are now fully closed, providing bubble tight shutoff for the main pipeline.

Pipeline Venting to Atmosphere

Block stations are required occasionally vent a section of the pipeline to atmosphere. This too is a demanding application, with the valve being  exposed to full differential pressure. This operation starts with all valves in the system being closed. Bypass valve 1 is then opened allowing pressure into the bypass station system. The vent valve is now slowly opened to release the pipeline pressure.  Plug valves are commonly used here again to ensure bubble tight isolation to the atmosphere once closed.

For more information, contact Mountain States Engineering and Controls by visiting https://mnteng.com or by calling 303-232-4100.