How Do Pilot Operated Tank Relief Valves Work?

Storage tanks become pressurized when liquid is pumped in and compresses the existing tank vapor. Tanks also become pressurized due to increasing ambient temperatures, which cause the tank vapor to expand. To mitigate damage from these expanding tank vapors, pressure relief valves are installed on tanks to prevent structural damage resulting from over-pressure.

Here is an excellent animation, courtesy of Cashco, that shows how a pilot operated relief vent protects a storage tank from over pressurizing during a pump-in situation or during thermal heating conditions.


For more information on tank relief valves, contact Miller Energy at www.millerenergy.com or by calling 908-755-6700.

Common Instrumentation Requirements for Industrial Boilers

Instrumentation Used on Industrial Boilers
Typical boiler instrumentation layout.
(courtesy of Yokogawa)
Boilers are used in a broad range of industries such as electric power, pharmaceuticals, chemicals, ceramics, and paper and pulp. Amid the rising energy costs, tightening environmental regulations, and increasing awareness of safety as of late, the needs for high efficiency operation, low emission operation, and safe and stable operation of boilers are growing.

In order to ensure the air and fuel are combusted at an optimal ratio, the waste of fuel is eliminated, and the exhaust gas is cleaned, real-time monitoring of the oxygen concentration of combustion gases is required. Equipped with an oxygen sensor unit with a longer life span, the Zirconia Oxygen Analyzer ZR series are capable of measuring an oxygen concentration with high reliability. The Stack Gas Analyzer monitors exhaust gas components such as NOX, SO2, and CO2 in order to ensure low emission operation.

A single-loop controller can be used to properly distribute control functionality. Offering the advantages of flexibility of building distributed control systems, simple maintenance, compatibility with conventional systems, and the like, the YS1000 Series of Single-loop Controllers are ideal for safe and stable operation at low costs.

In order to ensure highly efficient and safely operated boilers, it is also indispensable to accurately monitor the drum level and steam flow rate. The EJA and EJX Series of Differential Pressure Transmitters are capable of measuring the drum level with high stability even in actual applications at high temperatures and high pressures. The DY Series MV TYPE of Vortex Flowmeters with a simple construction employ a built-in sensor to measure the steam mass flow with high reliability.

Yokogawa offers a wide variety of sensors and controllers that are used to monitor and operate boilers, and contributes to increasing the efficiency and environmental performance of boilers, as well as ensuring their safe and stable operation.

Recommended Products for Boiler Applications


  • Drum Level Measurement - EJA/EJX transmitters
  • Combustion Control - The YS1000 Dual CPU Loop Controller
  • Steam Flow Measurement - Digital YEWFLO MV Type
  • Combustion Monitoring - Zirconia Oxygen Analyzers and AV550G Multi Oxygen Sensor Converter

For more information in Eastern Pennsylvania, New Jersey, Metro New York or Delaware contact:
Miller Energy by visiting https://millerenergy.com or by calling 908-755-6700 in New Jersey, or 610-363-6200 in Pennsylvania.

Detailed Look at the Yokogawa YS100 Series as a Replacement for the Obsolete Siemens 353

This video is a thorough presentation detailing why and how the Yokogawa YS1000 Series is the best replacement for the obsolete Siemens/Moore 353 controller. It is composed of a series of presentation slides - hit the pause button to focus on any single slide.

New Jersey: 908-755-6700 
Pennsylvania: 610-363-6200

Breakthrough Solenoid Valve Technology for Upstream Oil and Gas Heating Equipment

A white paper courtesy of ASCO Division of Emerson Automation
fuel shutoff valves
Fuel shutoff valves (ASCO)
Low-temperature stainless steel fuel shutoff valves are usually utilized for on/off control of fuel gas within gas fuel trains in process heating system burners. These systems are widely used by oil and gas firms as well by as original equipment manufacturers (OEMs) that produce gas heating equipment or burner management systems (BMSs) and controls in upstream oil and gas pipelines and tanks.

For valve manufacturers, these uses present a relatively specialized, rather challenging application. Environmental conditions at the point of use are often difficult. Ideally, valves should deliver reliable operation despite constraints on factors ranging from power consumption to service availability. Conversely, outdated controls can pose problems — including poor performance, noncompliance with current regulations, and triggering of environmental concerns.

In recent years, a new generation of solenoid valve technology has been changing the shutoff valve game. Their modern designs provide pipeline and tank heating systems with robust, durable performance; safety; and regulatory compliance — all while increasing efficiency and productivity.

Download the PDF version of "Breakthrough Solenoid Valve Technology for Upstream Oil and Gas Heating Equipment" here, or review it in the embedded document below.

Miller Energy, Inc.
https://millerenergy.com
New Jersey: 908-755-6700
Pennsylvania: 610-363-6200

An Excellent Replacement for the Discontinued Siemens 353 SLC

Siemens 353 replacement
The Yokogawa YS1700 is a great replacement to the
discontinued Siemens 353 SLC controller.

The discontinuation of the Siemens 353 SLC controller is a concern to many users of this popular controller. With few alternatives, customers are joking that they'll have to turn to eBay for spare parts. There's a much better solution though. The Yokogawa YS1700 PID loop controller, a drop-in replacement for the Siemens 353 SLC.

The Yokogawa YS1000 Series is the ideal choice for many control applications offering extreme reliability and sophisticated control. This product family has bright, easy-to-read displays, multiple I/O points, and powerful loop tuning. For critical applications, the YS1700 employs dual CPUs for maximum reliability and hard-manual control for added protection. The YS1700’s powerful function block programming allows for custom strategies to control many demanding processes such as boilers and steam generators, PH control, dosing control, and many other demanding plant processes.

To learn more about replacing the Siemens 353 with a Yokogawa YS1700, visit this page or go directly to this link https://millerenergy.com/Siemens-353-Replacement.

How to Select a Pressure Switch

UEC One Series Switch Transmitter Hybrid
UEC One Series Switch Transmitter Hybrid
Reprinted with permission from United Electric Controls

Pressure switches are widely used by many industries and within many applications. The basic function of a pressure switch is to detect a pressure change and convert it into an electrical signal function – typically on/off or off/on. Pressure switches may be of electro-mechanical or electronic/solid-state design (see our ONE Series); and while each may have its advantages, arriving at the correct pressure switch for your application is the same.

Set Point & Deadband


Application set point (sp) is the desired value reached at rising or falling pressure at which the micro-switch changes electrical states. Depending upon the pressure switch function, the micro-switch could be wired to open (turn something OFF)  or close (turn something ON) when set point is achieved, thereby triggering an event such as an alarm, equipment shutdown, or powering up secondary equipment. Ideally, the set point should fall into the mid 50% of the pressure switch range for best performance including repeatability and long life. On an electro-mechanical pressure switch, set point may be adjusted internally or externally either through blind adjustment or reference dial. An electronic pressure switch would have internal or external adjustment via a key pad and digital display or a handheld programmer.
Deadband graph

Deadband (DB) is the on-off differential required to reset the micro-switch. This value may be fixed or adjustable with an electro-mechanical switch and may be up to 100% adjustable on an electronic switch.

Deadband may be an important factor to consider depending upon the application requirements.

System Pressure


Knowing your normal and maximum system pressures will help in selecting a pressure switch with appropriate minimum and maximum operating parameters. Once your set point is established, other factors to consider are vacuum and/or surge pressure that could affect switch operation. This would involve maximum working pressure, over range pressure, and proof pressure specifications of a pressure switch. The relationship between set point and system pressure has a direct effect on switch performance and life.

Electrical Considerations


UEC 100 Series Pressure Switch
UEC 100 Series Pressure Switch
Micro-switches are available in a variety of configurations. The most common for electro-mechanical pressure switches is 15A, 480VAC SPDT (single pole, double throw). The advantage of a SPDT micro-switch is that it offers wiring flexibility to either open or close on pressure change. Other micro-switches available include 1A with gold contacts, useful when working with a PLC, or at the upper end, 30A when switching certain high voltage heaters or motors. Adjustable micro-switches help with deadband adjustment. A DPDT (double pole, double throw) micro-switch would provide two simultaneous functions off of one micro-switch. If a low-high limit alarm and shutdown were required, there are pressure switches that include two SPDT micro-switches that are independently settable.

An electronic pressure switch would use solid-state relays to change states. Like an electro-mechanical switch, the electronic switch can be programmed to open or close on rising or falling pressure. There are different capacities for switching voltage and current depending upon the application requirements.

Process Media and Wetted Parts


The pressure connection and sensor are known as wetted parts since they come into direct contact with the process media. Sensor material is either elastomer (i.e. Buna-N, Teflon®) or metallic (i.e. Brass, Stainless Steel) with metallic or composite pressure connections. The process media must be compatible with the wetted parts material. Process media temperature should also be considered as each of the different wetted materials would have differing operating properties.

Pressure Switch Mounting


If the unit is to be installed directly onto the process, there are many methods of installation.
Typically a 1/8”, 1/4”, or 1/2” NPT (national pipe thread taper) connection is used with a mating
fitting to secure the pressure switch to the process. There are also straight threaded (SAE, BSPT)
connections, flush mount connections, and sanitary connections. The pressure switch may be
mounted directly in the process line using the threaded connection, a manifold, or flange; or the
enclosure could be bolted to a mounting plate or other plane to secure it. If heavy vibration is
present, you may choose to use a remote diaphragm seal with the pressure switch. The diaphragm
seal mates with the process connection while the pressure switch enclosure is mounted securely
away from the vibration. 

Process Environment


It is important to know what type of environment the pressure switch would be installed in – hazardous or ordinary location; indoors or outdoors; exposed to salt air; inside a control panel; in high ambient temperature. These are just some of the factors to consider so the right enclosure type is chosen. Enclosure types come in many shapes, sizes, and materials. They also conform to various industry and third-party approval standards. Electronic switches can be used to replace electro-mechanical switches when SIL is needed for safety applications.  There are also electro-mechanical pressure switches without enclosures; typically used in OEM, non-hazardous locations where the environment is benign.

With careful consideration of all the factors listed above, choosing a pressure switch is a snap. If you are at all unsure, please contact your local United Electric Distributor or visit the UE Product Selector to find your pressure switch.