Float Actuated Oil Level Swichgage instruments are a combination oil level sight gage and adjustable, low and/or high limit switch.

The limit switches are normally open during operation — yet closed if the level drops (or rises) to where the float contacts the limit screw. The contact completes a circuit to ground a magneto or trip a Murphy magnetic switch. The magnetic switch can be used to activate alarms and/or shut down. Models are also available without limit switches. The level instruments can be used on a variety of crankcases, pump gearcases or oil reservoirs — primarily on small engines and pumps. Installation is simple, and these instruments save on reduced downtime and repair costs.

The LM300 Series Level Maintainer automatically adds oil to the crankcase as needed to keep the lube level normal.

Most models have built-in switches that will alarm and/or shut down the equipment if the makeup supply is depleted and engine oil level falls or if overfill conditions exist. The LM300 can be used in engines, compressors, pumps and coolers. LM300 Series EX models (explosion-proof) are CSA certified for Class I, Division 1 Hazardous areas.

The Murphy L971 Series Level Switch detects low oil level in a compressor’s crankcase.

As oil level in the crankcase depletes, the float on the L971 switch falls, and when reaching the predetermined limit, it will trip the internal snap-switch sounding an alarm or initiating shutdown. The L971 is designed for Ingersoll-Rand Type 30, Type 40 and ESH compressors, yet it can be adapted to fit other compressors that have an inspection plate extending below normal operating oil level. It installs with minimal downtime and has a two-year limited warranty. The L971 has a 1/2 NPT process connection and features an explosion-proof enclosure, durable SPDT snap-switch and rigid polyurethane foam float. A 304 stainless steel float is available on certain configurations.

The LM500 maintains oil level on any size engine.

As crankcase oil level drops, the LM500 float also drops and opens the Thumb-Valve™. This allows oil to flow from the supply tank through the LM500 and into the crankcase. When proper level is achieved in the crankcase, the LM500 float rises causing the Thumb-Valve to close off further oil flow. If the clean oil supply is depleted and oil level continues to fall, the low-level switch will operate an alarm or equipment shutdown.

The L150 Series Level Swichgage instrument is a combination liquid level gage and low-limit switch.

Each unit includes (1) a chamber with pivotal float, (2) an indicating dial with pointer and (3) a low-level contact. When properly installed and maintained, the float operates the pointer which, in turn, both indicates level during normal operation and closes a switching circuit if the level falls to the low-limit set point. The primary use of the L150/EL150K1 is for engine cooling systems, surge or expansion tanks, condenser radiator or vapor phase systems, pressurized or atmospheric systems. The Level Swichgage instrument can also be used to monitor lube oil, hydraulic fluid or diesel fuel reservoirs and activates alarms and/or shut down at a predetermined minimum level. These instruments are built for low pressure systems with a maximum of 25 psi (172 kPa) [1.72 bar].

The L129 Series Lube Level Swichgage instrument is a combination lube level indicating gage and adjustable low and high limit switches.

It provides protection against low oil level or high level caused by overfill or fuel or water seepage into the crankcase. A 6-3/4 inch (171 mm) deep sight gage allows you to check the condition and level of your oil without shutting down the equipment. Fingertip adjustable limit contacts, through 4-7/8 inch (122 mm) range, make it simple to set high and low limit contacts. When properly installed and maintained, the L129 Series Lube Level Swichgage can monitor and protect engines and pumps from improper lubrication level, which can result in extensive damage. The L129 Series is recommended for engines and pumps with larger crankcase capacity. Although designed primarily for stationary engines, the L129 Series is often used in mobile applications such as marine, rail and some large off-highway trucks.