Showing posts with label level control. Show all posts
Showing posts with label level control. Show all posts

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

Tuesday, November 3, 2015

Capable Single Tank Level Display Solution

Oil Refinery Storage Tanks
Oil Refinery Storage Tanks
Earlier this year, King Gage released their LP1 Tank Level Indicator. The unit provides a number of integrated features that give the user accurate indication of tank liquid level. Mate the LP1 with any level sensing instrument that produces a 4-20 ma output signal and it can calculate tank inventory based upon hydrostatic pressure or direct level measurement. Tank level is displayed directly in engineering units, referencing a capacity profile that correlates the transmitter output to actual tank geometry. All application parameters are preprogrammed at the factory, based upon supplied application data, and stored in nonvolatile memory. Options include an isolated 24 Vdc transmitter power supply, Modbus communications, and more.

This simple, accurate, flexible unit can be easily applied in many industrial process measurement and control settings. Discuss your application possibilities with a product specialist to save time and take advantage of their wide range of application experience.


Thursday, July 16, 2015

Downpipe Liquid Level Sensor Purge Control

Downpipe bubbler type tank level indicator
Arrangement for bubbler type tank level indicator
with purge control
Courtesy King Gage
Industrial process control often requires the measurement of liquid inventory volume or mass. If the material is contained within a tank of known shape and dimensions, the volume can be determined accurately by measuring the level of the liquid. Various means are used to determine the liquid level. One of the simplest is the downpipe sensor, sometimes referred to as a "bubbler", where liquid level is inferentially derived using differential pressure. The downpipe is a length of pipe that is open at the end extending down into the liquid contained within the tank. The top end is connected to a purging device that provides a controlled flow of pressurized air or gas into the pipe. The pressure maintained within the downpipe will reach an equilibrium with the pressure produced by the hydrostatic force related to liquid level in the tank or vessel. Accurate measurement of this pressure, along with a thorough knowledge of the liquid's properties, can be used to determine the depth of the liquid within the tank and the corresponding volume.

King-Gage manufactures several industrial process level measurement devices incorporating downpipe purge technology and differential pressure measurement. They have applications in inventory monitoring, process control, hazardous and explosion zones, ballast monitoring, and other areas that benefit from their simple operation, low maintenance, and ruggedness. The company, in its own words describes the unit as an...
...extremely rugged unit designed specifically for hazardous areas requiring flameproof or ATEX (Ex d) rating. A proprietary wet check assembly ensures positive seal of fluids to ensure containment integrity. Loop powered transmitter provides 4-20mAdc output while components are isolated from the process media by a continuous air purge. Total consumption rate is less than 0.083 scfm for energy saving operation with external air/gas supply.The only internal element is a simple length of pipe extending into the tank.
Rugged design requires no setup or air flow adjustment due to its differential pressure regulation that avoids dynamic pressure drops common to other bubblers. This ensures highly accurate level measurement and repeatability within ± 0.2% while preventing turbulence or foaming of tank liquid. Applications include water/wastewater, sulfur pits, most free flowing liquids (including slurries) and temperatures in excess of 160 °C (320 °F) as the transmitter is effectively isolated from the process by the air purge.
The slides below illustrate various installation configurations, including one for explosion hazard areas. Contact an application engineer for more detailed information.


Wednesday, December 10, 2014

Improving Maintenance and Reliability of Bubbler Systems


According to Wikipedia "an air bubbler system uses a tube with an opening below the surface of the liquid level. A fixed flow of air is passed through the tube. Pressure in the tube is proportional to the depth (and density) of the liquid over the outlet of the tube."

A common problem with many bubbler systems used in water and wastewater systems is long term accuracy and reliability issues. The need for scheduled maintenance is required because of the possibility of  tampering, failed solenoids, changing air flow rates, or clogged downpipes due to crystal formation - particularly in wastewater applications with high entrapped solids.

A better approach is to use a level transmitter for purge control. This solution offers a highly engineered single component that is easily retrofitted to bubbler installations. These purge transmitters automatically maintain an extremely low flow continuous purge (less than 0.02 scfm) regardless of liquid depth, and minimizing formations of crystals in the downpipe. The lag time during dynamic level changes is also eliminated. Furthermore, bubbler operation is tamperproof because there is no external regulator or needle valve (or rotameter) – internally a fixed differential is maintained over a precision flow orifice.

Transmitter purge (or bubbler) technology works reliably in the presence of vapors, and, unlike ultrasonics, can be used in media temperatures of more than 350°F. Bubblers are normally used in applications where foam, solid debris, sewage sludge, or turbulence make ultrasonic, radar, or float switch devices ineffective. The purge transmitter is relative compact in size and allows for installations in tanks where other systems won’t fit.

The purge control transmitters require a compressed air supply (35-150 psig/2.4-10.3 bar) and provide a two-wire 4-20mA output that can be transmitted over substantial distances. The transmitter can be mounted directly outdoors or within small enclosed spaces at the measuring point or up to a hundred feet away.

More information on the purge transmitter may be download here.

Wednesday, August 20, 2014

Level Measurement

level measurement
Level Indicator
(King-Gage)
Level measurement is an important process measurement. In many processes, it is important to measure the level of various liquid and solid materials. Effective level measurement provides reliable and continuous operations by maintaining optimum material inventory, by maximizing plant availability, and the prevention of spillages and other process disturbances.

Level is measured at the interface between two material "phases", that is, between liquid and air or solid and air, or other different density materials. The different phases must be clearly separated. When liquids are thoroughly mixed together, level cannot be measured because there is no separation of phases. The interface must be definite in nature.

In the case of an open tank filled with water, the point at which water and air contact is the definite interface, or phase change. Another interface example would be between oil and water. In this example, the specific gravity of oil is less than water, so oil floats on top, but in separate form. Liquids that mix well together do not have a clear interface, so it is difficult to determine level of each.

Friday, July 11, 2014

Hydrostatic Tank Level Measurement

pressure transmitter
King-Gage pressure transmitter
One of the most proven and reliable methods of continuous tank level monitoring is remotely monitoring hydrostatic pressure.

Hydrostatic pressure is defined as "The pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. Hydrostatic pressure increases in proportion to depth measured from the surface because of the increasing weight of fluid exerting downward force from above.

Pressure transmitters are a simple and accurate choice for measuring liquid level in storage tanks or processing tanks.

hydrostatic level
Typical hydrostatic level application
The principle behind hydrostatic, pressure-based, liquid level measurement is simple since pressure is proportional to the level of liquid multiplied by the specific gravity. The specific gravity of a liquid is the ratio of its own density to the density of water.

Alternatively, level equals the hydrostatic head pressure value divided by the density of the liquid.