Series |
N/A 738 |
Type |
N/A LiquiSeal™ Purge Control Level Transmitter |
Range of Adjustment |
N/A 0 to 83 inH2O thru 0 to 138 inH2O /0 to 2.1 mH2O thru 0 to 3.5 mH2O |
Note for Span Adjustment Range |
N/A IMPORTANT! Accuracy, linearity, and non-repeatability values are based on nominal range. |
Temperature [Min] |
N/A -16 ºC0 ºF |
Temperature [Max] |
N/A 54 ºC120 ºF |
Materials of Construction |
N/A Machined brass body with acrylic semi-gloss enamel finish; integral filter element is aluminum with acrylic semi-gloss enamel finish. |
Burst Pressure |
N/A 200 psig |
Fittings |
N/A Polyflo; (1) 3/8 in. tube, (1) 1/4 in. tube x 1/4 in. National Pipe Thread (NPT) |
Accuracy |
N/A ± 0.34% Full Scale |
Depth Measurement [Max] |
N/A 1,937 inH2O49.0 mH2O |
Electronic 4 to 20 Milliampere (mA) Output |
N/A D/P Purge Control or D/P LiquiSeal™ transmitter provides a 4-20 mA output over a two wire cable to an indicator or the analog I/O of a PLC. Using twisted pair shielded cabling permits transmission distances of several thousand feet to a remote receiver. |
Output Signal (Milliampere Direct Current (DC) (mAdc)) |
N/A 4 to 20 mA |
Direct Current (DC) Power Supply Voltage (Unregulated) |
N/A 14 to 40 V |
Repeatability |
N/A ± 0.20% of Calibrated Span |
Flow Rate (Air Purge) |
N/A
Nominal 1 cfh (Cubic Feet Per Hour) at Specified Differential Maximum Air Consumption Under 5 cfh (Cubic Feet Per Hour). |
Voltage/Load Capacity Ratings |
N/A The KING-GAGE® D/P Transmitter requires a source of DC power for operation. The minimum excitation voltage necessary for the transmitter is 10 Vdc. Any receiving components (meters, data recorders, programmable controllers, etc.) installed in the process loop circuit must be taken into account when determining the required power supply voltage. The internal resistance of each device added together represents the total “load" residing on the circuit loop. |
Nominal Span Adjustment Range |
N/A 0 to 5 psid |
Span Adjustment Range [Min] |
N/A 0 to 3 psid |
Pressure [Max] |
N/A 300% Over-Range |
Pressure Range |
N/A 0 to 5 psid |
738 Differential Pressure LiquiSeal™ Purge Control |
N/A The above model but adds an integral differential pressure (D/P) transmitter converting pneumatic pressure into 4-20 mAdc electronic output. |
Operating Limit (Maximum Pressure) |
N/A
Pressure above 300% nominal range (overrange) will result in damage to the transmitter (200% may cause a shift in calibration). Burst pressure is 200 psi and will cause catastrophic and physical failure of the pressure element. Indication is then provided directly as the total weight or volume of liquid in the tank. |
Differential Pressure Purge Control |
N/A Unit incorporates differential air flow regulator with flow control orifice. Fixed differential set to nominal 10 psid. Output is 1:1 pneumatic pressure (hydrostatic force equivalent). Includes an integral differential pressure (D/P) transmitter converting pneumatic pressure into 4 mAdc to 20 mAdc electronic output. |
Pressure to Milliampere (mA) Conversion |
N/A
KING-GAGE® D/P Transmitters accept either gage or differential pressure pneumatic inputs that are converted to a proportional 4-20 mA output signal. This two wire signal loop is compatible with typical process components that accept analog input including PLCs. Designed to operate over a broad voltage range, these transmitters work with power sources ranging from 14-40 Vdc (based on load requirements). Output current limiting and continuous no-load operation ensures reliability in even the most demanding situations. Isolated test meter terminals permit in-process monitoring for troubleshooting. This allows the user to easily check the transmitter output without having to remove it from the process loop circuit. |
Pressure Ranges are Span Adjustable |
N/A Transmitter span accommodates a 3:1 turndown ratio (3:1 turndown ratio is applicable to 0-10 and 0-30 nominal range, refer to specifications for detailed span adjustment available on specific range models.) to match the application pressure range (i.e., tank depth). This permits ranging of the device to provide full scale output for maximum resolution in process control operations. Individual transmitter ranges of 0-5 through 0-50 psid are offered. These yield far greater stability than comparable single range units requiring high turndown ratios to fit the application. |
Compressed Air Requirement |
N/A
35 psig to 150 psig supply pressure at control inlet. (Minimum supply pressure should be at least 20 psig greater than anticipated maximum liquid head pressure.) All pneumatic instrumentation requires extremely clean, dry and oil-free compressed air. It must be noted that failure to use adequately filtered compressed air will result in unsatisfactory performance. Use of a compressed air coalescing filter (such as the King Air-Guard or King Air Control Station) upstream in the supply line is expressly recommended. |
Downpipe Level Sensor |
N/A
When purged with compressed air, liquid within the downpipe is displaced by air pressure equal to the hydrostatic force of liquid in the tank. If carefully regulated at a low rate of flow, air pressure will constantly maintain equilibrium against the force of the liquid. Air escapes out through the bottom of the pipe unless needed to increase pressure as liquid force (depth) increases. The primary sensor element is typically 3/4 in. diameter pipe purchased from a local source. Always select piping material for compatibility with the tank contents. Downpipe purge systems can be used to measure virtually any type of liquid product including resins, asphalt or corrosive materials. Output is proportional to liquid depth and can be transmitted as an electronic 4-20 mA signal or pneumatically as a direct 1:1 pressure signal. |
LiquiSeal™ Purge Control |
N/A
LiquiSeal™ D/P purge control is a fully integrated air purge regulator and level transmitter. Operation is based on the control regulating a continuous 1 cfh (cubic foot per hour) flow of compressed air into the tank downpipe. An internal differential pressure sensor element converts resulting pressure into a 4-20 mAdc two wire signal. An all-pneumatic version of the LiquiSeal™ purge control is available. It provides a 1:1 pressure signal to a compatible indicator or external transducer through 1/4 in. airline tubing. All LiquiSeal™ purge controls feature an internal isolation diaphragm. Backpressure created by the continuous purging of the downpipe is applied to this internal diaphragm. Working as a pneumatic transmitter, an equivalent pressure is generated on the gauge side of the diaphragm. This process effectively isolates downstream components from contact with the liquid or vapor releases. |
Pneumatic Output Signal |
N/A Purge Control or LiquiSeal™ Control provides air pressure signal to an external transmitter or compatible indicator (with integral transducer). Typically, 1/4" poly or soft copper tubing is used to convey the pressure signal up to 1000 feet from the tank. |
Downpipe Liquid Level Sensor |
N/A Control regulates compressed air flow to pipe extending down toward tank bottom. Depth of liquid causes air pressure to increase or decrease proportionally. A differential pressure (D/P) transmitter provides a 4-20 mA signal that can be used for remote indication or process control functions. |
Pneumatic Output to Indicator |
N/A Purge Control continuously purges tank downpipe and creates pressure corresponding to hydrostatic head of liquid. This pressure signal is conveyed through 1/4 in. airline tubing to a compatible electronic or pneumatic column indicator. |
Electronic Output to Indicator |
N/A D/P Purge Control senses hydrostatic pressure due to liquid depth and transmits a proportional 4-20 mA output. KING-GAGE® indicator correlates level to tank geometry to display actual volume amount (or weight) of liquid in tank. |
Hazardous Zone Service |
N/A The downpipe sensor and pneumatic components are fully compatible with explosion hazard environments. This makes pneumatic the sensible alternative for hazardous areas without the cost and complications of intrinsic safety barriers or explosion-proof products. Assumes only pneumatic components are situated in explosion hazard zone. |
Pneumatic or Electronic Output |
N/A These pressure-based level transmitter provides output proportional to depth. 735 LiquiSeal™ generates a pneumatic 1:1 pressure signal that can be transmitted to a suitable indicator or pressure transducer. 738 D/P LiquiSeal™ provides a direct 4-20 mAdc electronic output compatible with most receivers or analog I/O devices. |
Principles of Operation |
N/A
Purging a downpipe with compressed air creates a force balance, resulting in pneumatic pressure equal to the hydrostatic pressure due to liquid depth in the tank. The LiquiSeal™ Purge Control works as a constant flow regulator, providing a continuous flow of air (1 cfh) into the downpipe. Pressure is created as liquid is purged from the downpipe. This pneumatic pressure is the basis for the tank level measurement because it is equal to the hydrostatic (liquid) pressure which is directly proportional to liquid depth. For any increase or decrease of depth, there will also be a corresponding change in the pneumatic pressure. When equilibrium exists (i.e., air pressure = liquid pressure), the continuous flow of air escapes through the open end of the downpipe. This air bubbles up through the liquid hence the reason why this type of level sensing is often termed a "bubbler". |
Gauging System |
N/A
A complete tank gauging system can be configured using pneumatic components or can include electronic transmitters and indicators. Pneumatic sensors and indicators are inherently safe and explosion proof since there are no electrical components involved. A pneumatic system transmits a pressure signal through small bore tubing (typically 1/4" OD) to the pneumatic indicator. The location of the indicator may be up to several hundred feet from the LiquiSeal™ control. An electronic system using the D/P LiquiSeal™ generates a 4-20 mA signal to the indicator. This electronic signal can be transmitted over several thousand feet using twisted pair (2-wire) cable. The indicator can be either an analog column display or digital readout, depending upon preference. Since the primary element of either system is merely an open-ended pipe, the variety of material selections assures compatibility with tank contents. It may also be readily replaced by the user from any conveniently available source. |
Ballast Tank Indicating System |
N/A LiquiSeal™ control provides compressed air flow to downpipe. The tubing (3/8-in. OD) also conveys the resulting pressure due to liquid depth. The purge control then retransmits an isolated pneumatic signal or 4-20 mA electronic signal to the indicator. |
Differential Pressure Purge Calibration Kit |
N/A TL-190: Differential Calibration Kit |
Differential Pressure Pneumatic Sensor Controls |
N/A
The KING-GAGE® D/P Transmitter is also offered in a hybrid version combined with an air flow control for pneumatic sensors or downpipe (bubbler) systems. These combination units allow for direct 4-20 mA signal from the tank using the integrated differential pressure transmitter. D/P Sensor Controls are designed for use with KING-GAGE® pneumatic diaphragm sensors. The air control portion of these units creates a 1:1 pneumatic pressure directly proportional to liquid depth in the tank. Acting as a force balance, the pneumatic pressure offsets the hydrostatic pressure exerted against a diaphragm at the tank. The electronic transmitter then converts this pressure into a 4-20 mA output signal. D/P LiquiSeal Controls and D/P Purge Controls are used in conjunction with a downpipe (or bubble tube) extending down through the liquid contents of the tank. This type of sensor also acts as a force balance. A continuous purge of compressed air into the pipe displaces the liquid and creates a pneumatic pressure equivalent to hydrostatic head pressure. The transmitter converts this pressure into a 4-20 mA output signal. |
Transmitter Signal Loop |
N/A
As is typical of two wire transmitters, electrical power to the signal loop is supplied through twisted pair cable. Excitation voltage (+V) is provided by the receiving device or from a separate Vdc power supply installed in the loop. The actual voltage necessary for operation of the system will depend upon the overall load resistance of the loop. In most applications, the KING-GAGE® Digital Indicator or LevelBAR indicator provides 24 Vdc excitation to power the transmitter signal loop. |
LiquiSeal™ Purge Control Service Parts |
N/A
LiquiSeal™ Purge Control Service Parts 7333-10: Replacement filter element 7334-9: Air control section kit 7334-21: Sensor section kit (Includes 7366-1 orifice check valve and 6448-22 Titanium diaphragm) 7336-1: Orifice/check valve 6448-22: Sensor diaphragm, titanium 9316-4: O-ring for D/P top plate |
Draft Indicating System |
N/A Length of pipe penetrates hull a point below minimum water line. Output from the purge control proportional to liquid depth is transmitted to the indicator which displays actual draft measurement. |
Downpipe Check Valve |
N/A
Downpipe Check Valve 6363: Downpipe float check valve, 3/4" NPT connections 6563-10: Downpipe float check valve, 3/4" NPT outlet, 3/8" tube inlet
Material: 304 Stainless Steel, Nylon (float), FKM (seals) Maximum Pressure: 150 psig Inlet/Outlet: 3/4" NPT-female Weight: 1.2 lb (0.5 kg) |
Tank Top Fittings |
N/A
1-1/2" NPT Tank Top Fitting (for 3/4" Pipe) single purge line connection with tube fitting 7746-13: Carbon Steel, polyflo 3/8" tube 7746-15: Carbon Steel, Swagelok 3/8" tube 7746-18: 316 Stainless Steel, Swagelok 3/8" tube 1-1/2" NPT Tank Top Fitting (for 3/4" Pipe) with single 1/4" NPT purge port connection 2000FA: Carbon Steel 2000PA: PVC 2000SG: 316 Stainless Steel 1-1/2" NPT Tank Top Fitting (for 3/4" Pipe) with two 1/4" NPT purge/equalizer connection 2000FA-2: Carbon Steel 2000PA-2: PVC 2000SG-2: 316 Stainless Steel |
Tank Level and Draft Applications |
N/A
The LiquiSeal™ Purge Control can be used to sense tank levels or measure ship's draft. The output signal (pneumatic or electronic 4-20 mAdc) can be transmitted to KING-GAGE® indicators in the engine room, control center or ship's bridge. Applications Include:
|
Application |
N/A
|
Tank Gauging Applications |
N/A
A complete tank level gauging system can be configured using either pneumatic Purge Controls or D/P Purge Controls. The output signal can be routed to either a analog column display or digital readout. Acting on the force balance principle, a pneumatic sensor generates air pressure equivalent to the hydrostatic force created by liquid depth. This pneumatic pressure is directed into the D/P transmitter. Pressure is converted to an electronic 4-20 mAdc output proportional to liquid depth. Twisted pair cabling is used to form the signal loop through which the remote indicator receives the transmitter output. The KING-GAGE® indicators shown in these system views correlate the transmitter output to total volume or weight of tank contents. This is determined by using a pressure versus capacity listing corresponding to the actual tank dimensions. |
Additional Information |
N/A
Purge Controls
D/P Sensor Control
LiquiSeal™ Downpipe Purge Control
LiquiSeal™ Purge Control is a fully integrated air purge regulator and pressure transmitter. It can be mounted directly adjacent to the tank or remotely up to 50 feet away. 3/8" air line tubing connects the LiquiSeal™ unit to the pipe extending downward in the tank. A supply of compressed air is required for system operation. The rugged brass construction is especially suited to the rigors of marine service. Beneath a durable gloss epoxy finish, the machined brass body and housing resists corrosion while affording maximum protection. For explosion hazard areas, an all-pneumatic version of the LiquiSeal™ can be used without the need for intrinsic safety provisions. |
Product Warranty |
N/A
All KING-GAGE®, a NOSHOK Company products are guaranteed to be free from defects in material and workmanship for one (1) year from the date of purchase. Repair Services Warranty: 90 days limited warranty. |
Prop 65 Warnings |
N/A
 WARNING: This product can expose you to chemicals including Lead and Nickel, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov |
