Electrostatic precipitators
ESP penthouse
Also known as penthouse (ESP), rapper penthouse.
The ESP penthouse is the gas-tight compartment immediately above the plate stack of an ESP. It houses the rappers (in American-style designs), the high-voltage bus insulators, the discharge-electrode support frames and access for inspection and maintenance.
Why the penthouse matters
The penthouse environment is hot, dusty and electrically energised — and yet must remain accessible for servicing the MIGI rappers and HV insulators on every outage. Insulator contamination from penthouse dust is one of the most common causes of HV trips: a dust film provides a creep path from the discharge-electrode bus to ground, suppressing corona and tripping the T-R set.
Sonic horns on the penthouse
Sonic horns mounted through the penthouse roof project sound downward into the upper plate volume, the discharge-electrode bus area and the insulator compartments. This keeps the upper region of the field clean — exactly the area that MIGI rappers reach least effectively — and reduces insulator fouling and HV trips at the same time.
Related terms
Related terms
- Electrostatic precipitatorAn ESP removes particulate from flue gas by charging dust and collecting it on plate electrodes. Sonic horns are widely used to dislodge ash from plates and to keep hoppers from bridging.
- ESP rapperAn ESP rapper is the mechanical hammer or magnetic impulse device used to dislodge accumulated dust from ESP plates and discharge electrodes. Sonic horns complement and partly replace this duty.
- Magnetic-impulse-gravity rapperA MIGI rapper lifts and drops a steel plunger by electromagnet onto an anvil rod connected to the ESP collecting plate. Standard design in American-style ESPs from B&W, Mitsubishi and Hamon.
- Sonic hornA sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.