Description

CPT series marine ejector

一.Overview This series of jet pumps are used as drainage and condensate removal equipment in shipboard drainage systems.

二. Main Technical Performance Parameters

model	flow m3/h	Working water pressure MPa	Working water consumption m3/h	Net suction height m	Discharge pressure MPa
CP5-0.3T	5	0.3	6	4	0.05
CP10-0.3T	10		12
CP15-0.3T	15		19
CP20-0.3T	20		24
CP30-0.3T	30		36
CP40-0.3T	40		47
CP50-0.3T	50		55	3	0.06
CP100-0.3T	100		110
CP5-0.7T	5	0.7	3.6	4	0.08
CP10-0.7T	10		7
CP20-0.7T	20		14
CP30-0.7T	30		21
P30/20-0.7	30		40	5	0.15
CP50-0.7T	50		35	4	0.08
CP60-0.7T	60		50	6	0.06
CP80-0.7T	80		90	5	0.10
CP100-0.7T	100		60	2	0.09
CP150-0.7T	150		100
CP200-0.7T	200		120
CP100-0.7G	100		90	5
CP15-0.5T	15	0.5	25	7	0.11
CP10-1.0T	10	1.0	16.7	5	0.2
CP50-1.0T	50		64
CP100-0.2T	100	0.2	305	3	0.07

How to choose a CPT marine jet pump?

When selecting a CPT marine jet pump (usually referring to a steam/air-driven jetting system, primarily used for bilge/sewage/waste oil suction, vacuum priming, waste discharge, and tank evacuation), the key is not the pump head, but rather matching the required suction capacity with the available driving medium (steam/compressed air/water) and the back pressure and vacuum level. The selection process can be followed as follows.

1. First, confirm which type of drive you mean by “CPT jet pump”.

Three common types of ejectors/pumps on ships:

Steam ejector
Air ejector
Water jet pump (using fire pumps/seawater pumps as power source)

Different drive media determine: energy consumption, achievable vacuum level, applicable media, explosion-proof requirements, and piping system.

2. Specify the pumped medium and operating conditions (determines throat size, material, and structure)

At least provide:

Pumped medium: Bulch water/sewage/sludge, waste oil, gas-containing liquid, seawater, chemicals, etc.
Temperature, solid/fiber content, corrosiveness (determines material: bronze, stainless steel, duplex steel, rubber lining, etc.)
Whether entrained gas is allowed: Jet pumps are more friendly to gas-containing conditions, but solids can wear down the nozzle/throat.

3. Key performance parameters: Suction volume, vacuum level, discharge back pressure

The three most critical factors for jet pump selection (all are indispensable):

Suction volume (pumping capacity)

Liquid pumping: m³/h
Vacuum pumping/gas pumping: m³/h or kg/h (in air equivalent)
Suction conditions/target vacuum level

Suction height (pump to liquid surface height difference)

Required vacuum level (kPa abs or (mmHg) Resistance of suction pipe length, diameter, elbows, filter screen, etc.

Note: Higher vacuum requirements may necessitate more ejector stages, increasing drive medium consumption.

Discharge back pressure

Pressure/level before discharge into overboard, sludge tank, collection tank, oil separator, etc.
Discharge line losses
Higher back pressure requires greater drive pressure, resulting in lower suction capacity.

When selecting a model, always request the manufacturer to provide performance points based on the combination of “suction vacuum + discharge back pressure + drive pressure,” not just “maximum suction capacity.”

4. Driving Medium Conditions (Determines whether standards can be met and the consumption level)

Confirm the available driving conditions and allow for margins:

Steam Jet Pump: Steam pressure, temperature (superheating/saturation), available steam volume, condensate recovery/drainage
Air Jet Pump: Compressed air pressure, dew point/oil content, air supply (Nm³/h), noise and exhaust treatment
Water Jet Pump: Power water flow rate/pressure (usually from fire pumps/seawater pumps), whether mixing the suction medium with the power water during discharge is permissible

And calculate: Whether the driving pressure will still be met under off-peak operating conditions on board (multiple devices using air/steam/water simultaneously).

5. Piping System and Layout Considerations (Highly Impactful)
* The suction line should be as short and wide as possible with minimal bends to avoid air pockets at high points.
* Check valves and filters/suction nozzles should be installed as needed (but filter pressure drop will reduce capacity, so allowance should be made for clogging).
* Consider the pipe diameter and anti-scouring measures for both gas and liquid phases on the discharge side.
* Steam ejectors should have condensate and steam traps to prevent water hammer.
* Air ejector exhaust may contain oil mist/odors; silencers and other treatments should be implemented if necessary.

6. Materials and Wear Resistance
* Seawater/Corrosion: Bronze and duplex stainless steel are preferred.
* Sand/Mud: Nozzles and throats must be wear-resistant (hardened stainless steel, replaceable bushings/nozzles).
* Waste Oil/Sludge: Pay attention to the sealing gasket material and anti-static grounding (especially for air-driven applications).

7. Verification and Delivery Documents (to be included in the technical specifications) To truly “choose the right” supplier, request these from them:

Performance curves/performance tables: Suction volume at your drive pressure corresponding to different suction vacuum levels and discharge back pressures.

Drive medium consumption (steam kg/h, air Nm³/h, motive water m³/h)

Permitted solid particle size/content, wear-resistant part lifespan, or list of replaceable parts

Material list (Nozzle/Throat/Body) and test reports

Classification society requirements (e.g., CCS/ABS/DNV/LR) and relevant certificates (if required by the project)