Models SL, ML, HL, MLE, SG, HG, UL, MLH and Model TLM521 Eductors
Startup Checklist
Before starting the eductor, complete these steps to ensure safe and reliable operation:
- Verify that all piping connections are securely tightened and free of debris.
- Confirm that pressure gauges are installed on the motive, suction, and discharge lines.
- Ensure all suction valves are fully closed prior to startup.
- Verify that the motive fluid supply is stable and within the design pressure range.
- Quickly open the motive valve to establish steady motive flow.
- Once motive flow is stable, slowly open the suction valve.
- For steam-driven units: Confirm proper operation of the condensate trap and verify that steam lines are adequately insulated.
- Monitor discharge pressure to ensure it does not exceed the published maximum limits.
1. Safety and General Warnings
Your safety is our top priority. Please read and fully understand this manual before installing, operating, or maintaining the eductor. Failure to follow these instructions may result in equipment damage, leaks, personal injury, or property damage.
- Always wear safety glasses and appropriate personal protective equipment when working near the eductor during installation or operation.
- Never exceed the eductor’s rated design pressure. Refer to the certified drawings or dimension sheets for specific limits. Exceeding these pressures will void the warranty and may cause equipment failure.
- Treat all eductor outlets and downstream piping as high-velocity discharge zones. Stay clear during operation.
2. Introduction – How Eductors Work
Eductors are simple, reliable devices that use the Venturi principle to pump, mix, or convey fluids without any moving parts. A high-pressure motive fluid is accelerated through a nozzle, creating a low-pressure zone that draws in (entrains) a secondary fluid or gas from the suction line. The streams mix and are discharged at an intermediate pressure.
Eductors can be used to:
- Pump or transfer liquids
- Mix liquids with chemicals or solids
- Convey solids within a liquid stream
- Pump gases using a liquid motive fluid
- Heat liquids using steam as the motive fluid (inline heating)
Important: Treat downstream piping as a high-velocity flow area.
3. Inspection Upon Receipt
Inspect the eductor immediately upon receipt:
- Verify the model number, size, and material of construction (stamped on the body or nozzle) match your purchase order.
- Carefully check for any shipping damage.
If discrepancies or damage are found, contact your Northeast Controls representative before proceeding with installation.
4. Installation Guidelines
4.1 General Installation Rules
Installation should be performed by qualified and experienced personnel. Follow these guidelines:
- Eductors may be installed in any orientation; however, position them to allow complete drainage when the system is shut down.
- Ensure all piping is clean and free of debris—foreign material can clog the nozzle and impair performance.
- The eductor is not designed to serve as a structural support. Do not impose piping loads on the unit body; install adequate pipe supports as needed.
4.2 Piping Recommendations
To achieve maximum performance:
- Minimize backpressure on the discharge side.
- Install pressure gauges on the motive, suction, and discharge lines for easy monitoring and troubleshooting.
- Suction piping should be equal to or larger in diameter than the eductor’s suction connection to reduce friction losses.
- Consider installing a check valve in the suction line (with a pressure drop of less than 2 PSI) to prevent backflow.
5. Installation by Application
5.1 Pumping Liquids
- Install the eductor to minimize discharge backpressure.
- Ensure suction piping is completely airtight—any leak will significantly reduce or eliminate suction performance.
- Two close-coupled elbows or a light-duty check valve can help the eductor establish a proper seal during startup.
5.2 Inline Heating (Steam Motive)
- Follow all guidelines for pumping liquids.
- Position the steam connection upward whenever possible to facilitate condensate drainage.
- Limit steam superheat to 20°F or less for best performance.
- Properly insulate and size all steam supply lines.
- Install a steam trap when rapid heating or precise condensate control is required.
- For difficult startups, consider adding an overflow or relief line to safely manage initial discharge pressure.
5.3 Pumping Gases with Liquid Motive
- Position the discharge line at least 30° below horizontal to prevent liquid from entering the suction line.
- Warning: When using steam as the motive fluid, one end of the eductor may become hot while the other becomes frosted. Exercise caution around temperature differences.
6. Operation Procedures
General Operating Guidelines
- Always open the motive fluid valve quickly and fully. Gradual opening may prevent the eductor from establishing proper flow and vacuum.
- Open suction valves slowly only after stable motive flow has been achieved.
6.1 Pumping Liquids
- Quickly open the motive fluid valve to establish flow.
- Slowly open the suction valve.
- Adjust discharge valves only as needed, ensuring discharge pressure remains within allowable limits.
6.2 Heating Liquids (Steam Motive)
- Quickly open the motive steam valve.
- Gradually open the suction/liquid valve until the desired temperature is reached.
- If a relief valve is installed, close it once stable flow and temperature are achieved, then adjust discharge pressure as required.
6.3 Pumping Gases
- Quickly open the motive valve to establish flow.
- Slowly open the suction valve.
- Adjust discharge valves only within the unit’s design pressure limits.
Priming Pumps (Special Procedure):
Once liquid reaches the eductor, close the suction valve, start the pump, and then shut off the motive flow.
7. Maintenance Procedures
Before Performing Maintenance
- Ensure the entire system is fully depressurized, drained, and purged.
- Allow all components to reach ambient temperature before disassembly.
Preventive Maintenance Checklist
Perform regular inspections for:
- Nozzle erosion, clogging, or accumulation of debris
- O-ring wear or signs of leakage
- Corrosion or debris buildup in ports and connected piping
- Blocked strainers or malfunctioning steam traps
- Wear on the nozzle, body, or other internal components
Note: Maintenance frequency should be based on your specific process fluids and operating conditions.
8. Troubleshooting Guide
Note: This guide addresses the most common operating issues. Always follow proper lockout/tagout and safety procedures. Ensure the system is fully depressurized, drained, and at ambient temperature before any inspection or cleaning. If the problem persists after these steps, contact Northeast Controls Incorporated for assistance.
8.1 Low Suction Flow (Pumping Liquids)
If you are experiencing lower-than-expected suction flow:
- Suction piping restrictions
Reduce friction losses by clearing obstructions, increasing pipe diameter, or shortening the suction line where possible. - Excessive discharge backpressure
Minimize restrictions in the discharge piping and valves to lower overall backpressure. - Insufficient motive fluid pressure
Increase the motive fluid supply pressure to the recommended operating level. - Air leaks in the suction piping
Inspect the entire suction line and all connections; repair or seal any leaks immediately.
8.2 No Suction (Pumping Liquids)
If the eductor is producing little or no suction:
- Process fluid temperature too high
Lower the fluid temperature or reduce suction line restrictions to prevent cavitation or flashing. - Vapor pressure higher than expected
Adjust operating conditions (temperature or pressure) to stay within the eductor’s design limits. - Motive nozzle obstructed
Safely shut down the unit and thoroughly clean the motive nozzle. - Suction port or connection obstructed
Clear any debris or blockages from the suction inlet.
8.3 Heating Liquids (Steam Motive) – Steam Problems
Common symptoms: Live steam discharge, excessive vibration, loud noise, or steam exiting the suction port.
Possible causes and corrective actions:
- Discharge pressure increased before stable flow was established
Shut down the system and restart following the correct startup procedure (quickly open the motive valve first, then slowly open the suction valve). - Motive pressure too low
Increase the motive steam pressure to the required operating level. - Discharge pressure too high
Reduce discharge pressure or install/use a temporary startup relief/overflow line to a safe location.
9. Typical Components
Standard eductor assemblies typically include the following components (refer to the diagrams in the original manual or your certified drawing):
- Motive nozzle
- Nozzle O-ring
- Body
- Suction port
- Discharge port (and discharge O-ring on some models)
This manual provides clear, step-by-step guidance to help you install, operate, and maintain your eductor safely and efficiently. If you have any questions, contact Northeast Controls Incorporated for support.
Specific to Tank Mixing Eductors
Key Features Affecting Installation
The RTM TLM521 is designed specifically for in-tank mounting. This eliminates the need for expensive overhead structures, external supports, or complex external agitator mounts. Its compact size means it rarely interferes with other tank equipment (e.g., level sensors, baffles, or dip tubes).
- No moving parts — Virtually maintenance-free once installed.
- Any orientation works — The venturi-based design performs properly regardless of mounting angle (horizontal, vertical, angled). However, qualified personnel should always review the final setup to confirm desired mixing results.
- Connections — Available in male NPT, female NPT, ANSI flanged, or hygienic (ferrule/electropolished) options depending on the model variant.
Important: Always inspect the unit upon receipt. Model/size/material is stamped or cast on the body/nozzle. Do not install if it doesn’t match your order.
Piping and Preparation Best Practices
- Use clean piping free of debris, scale, or foreign matter that could clog the precision nozzle or diffuser.
- Motive fluid is typically recirculated tank liquid via an external pump (or steam for heating). Size the recirculation pump to deliver the required motive pressure/flow (typically 10–150 psig range).
- Minimize restrictions in motive, suction (entrainment), and discharge paths for best performance.
- For multi-eductor setups, a custom manifold is often used. Professional engineering support is recommended to optimize manifold design and positioning inside the tank.
- Do not impose structural loads on the eductor itself — support piping independently.
- Gauge ports (optional) can be added to monitor motive pressure and performance.
Warning: Treat the discharge plume as a high-velocity zone. Safety glasses should be worn during installation and operation. Exceeding design ratings can cause damage or injury.
Mounting and Positioning Guidelines
- In-tank placement — Mount the RTM TLM521 directly inside the tank, submerged in the liquid. The motive inlet connects via piping from the external recirculation pump.
- Location is critical — Proper positioning ensures effective circulation and eliminates stratification (temperature, concentration, or solids layers). Poor location can lead to dead zones or inefficient mixing, requiring troubleshooting later.
- For single units: Aim the discharge plume to create broad circulation (plume length ≈ 1 ft per psi of motive pressure).
- For larger tanks or viscous/slurry applications: Use multiple RTM TLM521s on a manifold, strategically placed (e.g., near bottom for solids suspension, or angled for tangential flow in circular tanks).
- Tank types — Suitable for open vessels or closed/pressure tanks. Works well in hazardous areas (no motors inside the tank).
- Hygienic installations (pharma/food) — Use electropolished 316SS with tri-clamp/ferrule connections; VFD on the pump is often recommended to adjust flow at varying liquid levels.
No rigid “one-size-fits-all” mounting diagram exists in the public manuals — each application benefits from custom review based on tank geometry, volume, fluid properties (viscosity up to ~2000 cP), and turnover requirements (often 1–3 turnovers for homogeneity).
Startup and Operation Notes (Relevant to Successful Installation)
- Verify all connections are tight and piping is clear.
- Open the motive fluid valve quickly (slow opening reduces effectiveness).
- Gradually open suction/entrainment paths.
- Monitor for proper plume formation and circulation.
- For heating applications (steam motive): Ensure proper condensate handling; limit superheat.
Maintenance
- Minimal — Periodically inspect the nozzle for erosion, debris, or wear.
- Check O-rings/seals if present.
- Clean if clogging occurs (rare due to open design).
- Relieve pressure and drain before any disassembly.
Troubleshooting tips (common post-install issues):
- Low/no entrainment: Check for restrictions, leaks in suction line, insufficient motive pressure, or debris in nozzle.
- Poor mixing: Reposition unit(s) or add more RTM TLM521s/manifold adjustments.
- Noise/vibration: Often from excessive back pressure or undersized unit.