Drainage Jet Pump for Hydropower Plants

Product Overview

The drainage jet pump is a critical component in hydropower plant drainage systems, widely used for turbine cover drainage, powerhouse leakage drainage, and sump sediment removal.

Powered by the energy of the working fluid itself—not plant auxiliary power—it can operate fully submerged. In blackout or emergency conditions, it continues to drain effectively, serving as a vital safeguard against powerhouse flooding.

Why Choose a Drainage Jet Pump?

Jet pumps have long been overlooked due to their relatively low efficiency (typically 28%–35%).

In leakage and emergency drainage applications at hydropower plants, however, their safety redundancy often outweighs pure hydraulic efficiency.

Key Advantages

No Power Required — Operates During Blackouts

The jet pump is driven by the energy of the working fluid and requires no electrical supply. When the plant loses auxiliary power, it continues to operate normally, effectively eliminating the risk of powerhouse flooding.

Flood-Resistant — Fully Submersible

The jet pump can be installed and operated fully submerged. Even if a valve misoperation floods the drainage system, it remains functional and rapidly mitigates the incident.

Proven Emergency Drainage Equipment

With a simple, stable design, it is ideally suited for emergency and contingency drainage, providing a final line of defense for powerhouse safety.

Replaces Slurry Pumps for Sump Desilting

The jet pump can remove accumulated sediment from collection sumps. Compared with conventional slurry pumps, it offers clear advantages:

1. Compact layout — installs directly inside the sump
2. Simple maintenance — no complex rotating machinery
3. Robust performance — air content in the water does not affect suction or desilting efficiency

When a water turbine is used to agitate sediment at the sump bottom, variations in dissolved air content do not impair the jet pump’s suction or desilting performance.

Applications

Application	Description
Turbine Cover Drainage	Removes leakage water from the turbine cover area
Powerhouse Leakage Drainage	Continuously removes water seeping into the powerhouse
Sump Desilting	Replaces slurry pumps to remove accumulated sediment
Emergency Drainage	Protects the powerhouse during blackouts or operational errors

Design Notes for Sediment Removal

When used to remove sediment from collection sumps, flow inside the pump is two-phase (liquid–solid). Performance equations, optimal area ratio, and other design parameters depend not only on conventional factors, but also on:

1. Concentration of the suction liquid
2. Specific weight of the suction liquid
3. Maximum particle size of the solids being conveyed

Therefore, sediment-removal jet pumps must be designed using mud/slurry jet pump performance curves and dedicated calculation methods.
Standard water jet pump formulas should not be applied directly.

Product Comparison

Feature	Drainage Jet Pump	Slurry Pump	Conventional Electric Pump
Power Required	No	Yes	Yes
Operates During Blackout	Yes	No	No
Submersible Operation	Yes	Limited	Limited
Emergency Drainage Capability	Strong	Moderate	Weak
Peak Efficiency	~28%–35%	Higher	Higher
Installation	Compact; direct sump mounting	Larger footprint	Dedicated pump room required

Suitability Guide

Recommended applications:

1. Powerhouse leakage drainage at hydropower plants
2. Continuous drainage when auxiliary power is unavailable
3. Emergency and contingency drainage systems
4. Sump sediment removal (requires dedicated design)

Selection guidance:
If safety redundancy, blackout protection, and emergency drainage are the priority, the drainage jet pump is the ideal choice.

Contact Information

Company Website: https://cd-greenwater.com
Technical Contact Number: 028-85130135
Customer Service Contact Number: 18515915124
Contact Email: jane1984@cd-greenwater.com
Address: No. 191, Section 1, Changcheng Road, Xihanggang, Shuangliu District, Chengdu