Vulcain gas detection systems are designed for use in a diverse range of commercial applications, from refrigerant systems and mechanical rooms to parking structures and office complexes. Each of these applications has its own set of requirements, both legal and practical, and Vulcain is committed to working closely with its clients to ensure all of these needs are met. In order to simplify purchasing and installation for our customers, Vulcain offers complete product packages for use in common gas monitoring situations.
- Refrigerants in mechanical rooms
- CO and NO2 in indoor parking garages
- CH4 in boiler rooms
- Freon in grocery stores
- CO2 for demand control ventilation
Some of the more common air quality hazards include:
HVAC:
Industrial
- Flammable gases
- CO, CH4, O2 and H2S in waste water treatment plants
- CO in aerospace, automotive industries
- Cl2 in pools
- Propane in ice arenas and parking garages
Video on Wireless Gas Monitoring
From stand alone to wireless networks Vulcain and Stromquist and Company has an answer for your gas and refrigerant monitoring system needs. Give us a call in Orlando at 1-800-638-7828 or in Atlanta at 1-800-241-9471.
In just about every application where the flow of air, water, oil, gas, or any other fluid needs to be stopped or started a solenoid valve is incorporated into the piping system.
Here is a list of common questions that need to be addressed to properly start the selection of your solenoid valve needs.
Valve Type 2-way, 3-way, 4-way
Operation Normally Open, Normally Closed, Universal
Pipe Size Pipe size or flow requirements
Media Fluid to be controlled (what’s going through valve)
Pressure Minimum and Maximum operating pressure
Temperature Minimum and Maximum fluid and ambient temperature
Voltage Voltage and frequency to be used
Extras Special seals, special seats, manual reset, explosion proof, etc.
Since most of the day by day uses of solenoid valves are 2-way/ 2-position let’s look at the above questions closer.
Operation This the most misunderstood question. Normally Open simply put means that when the valve is not energized (no power to coil) the valve is open allowing the media to pass through the valve. When the Normally Open valve is energized (power to coil) the Normally Open valve will shut down not allowing media to pass through the valve. The Normally Closed valve is of course opposite to the Normally Open valve. When the Normally Closed valve is not energized the valve will not allow media to flow through the valve. When the Normally Closed valve is energized the valve will open to allow media to flow.
Pipe Size Most all valves are listed by pipe size and Cv rating along with the valve’s orifice size. Notice that the smaller the orifice size is on a solenoid valve that the Cv rating is reduced. So what Cv do you need? Here is a “rule of thumb”. Cv = 50% of the gpm flow through a valve based on a 2-5 psi pressure drop between the inlet and outlet of the valve. So by way of example if you need 10 gpm of water to supply your need to some equipment with a 2-5 psi pressure drop the solenoid’s Cv factor would be 5.
Media Most common of media type for solenoid valves is air, water, gas, steam, or oil.
Pressure Maximum Operating Pressure Differential (M.O.P.D.) The maximum operating pressure differential refers to the maximum difference in pressure between the inlet and the outlet, against which the solenoid can safely operate the valve. If the pressure at the valve OUTLET is not known, it is safest to regard SUPPLY pressure as the M.O.P.D. Minimum Operating Pressure Differential is that which is required to OPEN the valve and keep it open. 2-way way solenoids with a floating piston or diaphragm, the valve will start to close below the minimum operating differential pressure.
Temperature The normal limitation of 32 degrees F (O degrees C) is advisable for any valve that might contain moisture (water Vapor). Where freezing water is not a factor, minimum ambience as low as 0 degrees F (-18 degrees C) can be tolerated. Special constructions are available for lower temperature ratings. Maximum ambient temperature is usually controlled by the UL listing for the coil insulation available for the valve.
Voltage There are various coil voltages available for solenoids to meet your needs. Please remember when asking for valves to state if the voltage is AC or DC and whether 50 or 60 cycles.
Stromquist and Company is proud to service your needs for solenoid valves by ASCO, GC Valve, and Honeywell. Let us help you pick the right solenoid valve for your needs by calling us at 1-800-241-9471 or 1-800-638-7828.
Stromquist & Company the Maxon Representative in Georgia is pleased to present this video on the Maxon Smart Link. The Smart Link is a way to percisely control the fuel air ratio saving energy by reducing the amount of fuel used. If you are in Georgia please contact us at www.stromquist.com to find out how we can save you energy.
Stromquist & Company founded in 1951 is the Maxon Representative in Georgia provide energy saving burner solutions to industry. Maxon is the quality producer of process burners, check out this video to learn more about Maxon’s history.
Gas metering is a big part of what we offer customers. One product that has proven to be very successful is the Honeywell Smart Multivariable (SMV) 
Transmitter. It is an industry leader – there are no others on the market that work as well. It measures the gas pressure & temperature and measures a differential pressure across a primary element. The primary element can be an orifice plate or a Preso Ellipse pitot tube. It creates a differential pressure that we measure and relate to flow (the square root of the pressure drop is proportional to the flow rate). The SMV calculates a corrected flow by accounting for the compressibility of the gas along with the pressure and temperature that exist in the pipe. It is quite an involved calculation that is pre-loaded into the transmitter and set up using a software wizard. Please keep it in mind for gas metering applications – it is an affordable alternative. For under $4000 you can measure big flows accurately with easy installation. Read More
Many people often ask about the difference between thermocouples and RTDs and the applications of these two devices. So here’s what you need to know:
The thermocouple is made of two dissimilar metals joined together at two points. The “hot junction” is in the process, and the “cold junction” is at the controller. In theory an EMF (Electromotive Force) i.e. a millivolt current, is generated at each junction that relates to the temperature at each junction. To measure a single temperature, one of the junctions (normally the cold junction) is maintained at a known reference temperature, and the other junction (hot junction) is at the process to be sensed. By incorporating an artificial cold junction compensator (a thermally sensitive device such as a thermistor or diode) the controller subtracts the temperature at the cold junction from the thermocouple’s signal to remove the cold junction’s error, thus giving a true temperature at the hot junction. This is known as cold junction compensation.
Unlike the thermocouple, the RTD (Resistance Temperature Detector) is usually made with a platinum, nickel, or copper wire that is wound around a ceramic or glass core, or it can be made by plating a thin film element and sealing this element within a ceramic or glass capsule. Since the RTD works on a change in resistance, the lead wires (from the RTD to the controller) have resistance and add an error to the signal. If the leads are long enough, then the error may be large enough to have to be corrected.
Industrial applications use a 3 wire RTD. Two wires connect on both sides of the resistor. This measures the temperature at the resistor and the error of the lead wires. One of those two wires has another wire with it. When those two wires are measured at the controller, they give the resistance of only those two wires. This measurement is then subtracted from the resistor’s two wires to remove the lead wire resistance from it. Now the controller is only reading the temperature at the resistor.
Application Differences:
Based on the thermocouple type (which dissimilar metals are used in manufacturing) the thermocouple has a wide temperature range: -328 to 4800 degrees F. Thermocouples have a fast response time, low initial cost, and durability for rugged industrial type applications.
RTDs have a temperature range of -328 to 1202 degrees F. Because of the lower temperature range, the RTD is more accurate than the thermocouple, has more stable outputs over time, and is easier to calibrate.
Explanation of these controls can get quite technical, and I would like to thank David Cates of our staff for his help in keeping terms and statements in a this article simple.
Let Stromquist and Company help you with your needs for thermocouples or RTD’s by calling us at 1-800-241-9471 or contacting one of our many CGNA members.
First, to understand these types of control you must have the elements of control. The elements of control are the sensor (senses the medium being controlled), the controller (device either preset or programmed to react to the sensor), and the final controlled device such as a damper or a control valve (receives input signals from controller to affect change in controlled medium). These elements are considered the control loop.
On/Off control is the basic type of control in a control loop. With On/Off control, the sensor senses the controlled medium and sends a signal back to the controller, which processes the signal. For ease of understanding, our example will be a heating application. The set point (the desired control point) in this case is 68 degrees with a temperature differential of 2 degrees for the controller. When the sensor’s signal to the controller reports a temperature of less than the controller’s set point, the controller sends a signal to the final control device (hot water valve) to position to fully open until set point is achieved. When the controller receives a signal from the sensor that the set point has been achieved, the controller then sends a signal to the valve to position to fully closed. The problem with On/Off control is over-shoot temperature of the desired system set point because of reaction time between sensor, controller, and final control device. Review: With On/Off, the controller asks “Is there an error?” The controller compares the actual value of the controlled medium to the set point through the sensor. As the controlled medium deviates from set point, the controller’s output cycles the final controlled device on, and when the set point is reached the controller’s output cycles the final control device off.
Floating control is a variation of On/Off control that requires a fast responding sensor and a slow-moving actuator connected to the final controlled device (valve or damper). Using the same example as the On/Off example above, when the sensed temperature drops below the set point of 68 degrees by the controlled medium’s sensor, the controller sends a signal to activate the actuator on the final control device. The actuator starts to slowly drive open the hot water valve, increasing the heat in the controlled medium. When set point is reached the actuator stops opening the final control device (hot water valve) and tries to hold at set point. If set point starts to be over-shot, the controller sends a signal to the actuator to start to drive close the valve. Review: Set point control is achieved when the sensor signal (from the controlled medium) starts to deviate from the controller set point. The controller sends a signal to the actuator of the final control device (valve or damper) to slowly drive open. As the set point is approached the controller sends a signal to the actuator, then the actuator stops and tries to maintain set point. If set point is passed the controller sends signal to the actuator to drive the final control device to a closed position.
Modulating/Proportional represents the higher end of control positioning. In modulating/proportional control the output varies continuously and is not limited to being fully open or fully closed. Proportional means that the size of the output is related to the size of the error detected by the controller. The key phrase for modulating/proportional control is “Continuous Control Action.” The sensor, controller, and final control device act as one unit to maintain constant precise control over the controlled medium. Continuing with the previous example, when a modulating system senses a deviation from the set point of 68 degrees, the controller calculates the amount of the error (1 degree less than set point) and sends a signal to the actuator, which will drive open the final control device (valve or damper) by a certain percentage of the controlled medium’s set point deviation (1/2 degree) to maintain set point without over-shoot. The controller calculates how much the final control device needs to open without over-shoot and will start reversing the actuator to close the final control device to a percentage of the closed position to maintain set point.
Popular modulating control signals include 4-20 ma and 0-10 volts. If you were to look into a control panel like a Hoffman Enclosure you might see controls like a Honeywell UDC3200 that could be taking a 4-20 ma signal from a device like a Hawkeye 908 current transmitter and based on the control input signal from the Hawkeye 908 ( which would most likely be a 4-20 ma signal) the UDC 3200 controller would respond with a 4-20 ma output signal to a device like a Honeywell Variable Frequency Drive which would control either a fan or a pump. This is an example of how a proportional signal like a 4-20ma signal is used in modern HVAC controls.
If you are in Georgia or Florida,the control pros at Stromquist & Company can answer your control questions.
There is nothing more frustrating than trying to start your boiler or burner; you hear the fan start, patiently wait for the sound of your ignition transformer to kick in and the roar of your burner light off, and nothing happens. The most likely cause of this problem is that your combustion air flow switch is not making.
The airflow switch is a burner/boiler safety device that proves (makes sure) that the combustion blower is running and providing the minimum amount of air pressure for safe light off, before we try to light off the burner. The airflow switch is wired in the preignition interlock circuit of a flame safeguard control. The sequence in which things happen is critical for safety in a combustion control system. The airflow switch being in the preignition circuit tells us that this switch must be made before the sequence can continue to ignition,which is why the combustion blower comes on and nothing else happens when the switch is not made. It could be very dangerous to open our main gas valves, allowing gas into the combustion chamber without having the necessary air flow that the combustion blower provides for proper and safe operation.
You can see “How to troubleshoot the combustion airflow switch” on Stromquist TV. Matt walks us through the steps of troubleshooting the airflow switch which include: 1) making sure the combustion blower is turning in the correct direction (you might laugh but it is one of the biggest causes of airflow switch problems our tech people get at Stromquist) 2) make sure your hook up tubes are the right size and not clogged 3) make sure your differential pressure is set properly. We like to use the Testo 510 ( available at Stromquist & Company) to set up our switches.
Differential pressure is an interesting subject in its own right. Not only is it used to prove things like air or water flow, but we also use it to measure flow. Put a know restriction in a pipe with flow.which creates a pressure drop, add an differential flow transmitter like the Honeywell STD900 or STD3000 and you have a very accurate method of measuring flow.
For more information on using DP ( differential pressure) to measure flow check out the following videos:
Meaning of DP transmitter high and low pressure ports
Back to Basics: DP Flow Measurement
If you are a Stromquist customer or are in GA or FL, call your Stromquist rep for help with your combustion and flow needs. All others, please refer to one of our affiliates at the Controls Group North America site to find a distributor in your area.
| Overview The ABC900 Advanced Burner Control is a PLC-based control tailored for burner and boiler applications. You’ll get integrated control with fuel-air ratio control, optional O2 trim, up to six actuator channels and up to two dedicated VFD channels. Optional drum level control with boiler feedwater control, optional draft damper control, fuel selection inputs and mass fuel-flow monitoring offer flexible boiler control. The ABC900 also interfaces with programmable flame safeguard controls. |
Features
• Works with HC Designer Software
• Process logic control platform
• Fuel air ratio control
• Up to six actutor channels
• Up to two dedicated VFD channels
• Interfaces with Flame Safeguard controls
• Up to three fuel selections
• Mass fuel-flow monitoring
• Drum level and draft damper control
Contact your Stromquist Representative for more information…
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