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HVS LPG-Vapor / Air Mixers

All HVS Systems are designed to be used with a new or existing LPG vapor source, such as a vaporizer, or as the replacement for less efficient or less reliable LPG vapor/air mixing systems. They come complete with steel skid, vapor inlet header, venturi arrangements, surge tank, mechanical/electronic controls, and all other equipment necessary for safe and reliable operation.

Installations where the mixer system is separated from an open-flame vaporizer, and installations with electric vaporizers, require the option "Explosion Proof Control Components", which includes explosion proof transmitters and solenoid valves. A local start/stop station in an explosion-proof enclosure provides basic control over the mixer. The main control panel for these mixers, with PLC and operator interface, must be installed in a non-hazardous location.

All HVS Mixers are equipped with two solenoid valves per Venturi train. The dynamic solenoid valve opens and closes each time a Venturi train is activated to produce mixed gas. The static safety solenoid valves opens when the mixer is started and stays open until the mixer is stopped, or until a high-pressure alarm occurs. This feature provides an additional level of safety and prevents the unwanted discharge of mixed gas in case of a failure of the dynamic solenoid valve.

All HVS systems monitor the gas pressure in the surge tank. Smaller systems of one or two venturi arrangements use pressure switches and mechanical controls. Larger systems with three or more venturi arrangements use a pressure transmitter which is connected to a Programmable Logic Controller (PLC; Siemens or Allen-Bradley). The PLC "sequences" the venturi lines and controls all system safety functions. The PLC also communicates with an Electronic Operator Interface (HMI) with color LCD display and touch screen, indicating system pressures, Venturi status, and any trouble conditions that may occur. The PLC may also be used to "interlock" the HVS system with an external vaporizer.

The required LPG vapor supply pressure depends on the desired sendout pressure, on the type of available LPG (Propane/Butane content), and on other factors (i.e. altitude). Typical supply pressures for Propane and 5-8 psi sendout pressure are 50-70 psi. Sendout pressures of 9-15 psi require High Pressure Configuration. Mixed Gas Sendout Pressures of more than 15 psi require the High-Pressure "Air-Assist" option, which includes an ASME "U"-stamped surge tank.

Please Note: Venturi-based LP/Air mixers are generally considered for intermittent use. Due to the finite service life of their dynamically exercised mechanical components (regulators, check valves, solenoid valves, air intake valves, etc. are typically specified to withstand 750,000 to 1,000,000 cycles), they are not very well suited for baseload applications. Their main application is Emergency Backup.

Compact HVS: Models with one or two Venturi trains (HVS-7, HVS-10, HVS-14, HVS-20) come in Compact configuration standard (as shown at right). These models are specifically designed for air freight shipment (small footprint, reduced height, removable relief valve stack, horizontal receiver tank, etc.).