---
title: "Shock-pulse generator (SPG)"
description: "A shock-pulse generator (SPG) — most commonly the Valmet SPG — generates high-energy gas-detonation shock waves inside a recovery boiler for periodic deep cleaning of superheater and generating-bank deposits. The technology shares its physical principle with detonation cleaning but is specifically engineered for kraft-recovery-boiler service."
canonical_url: "https://sylio.co/glossary/shock-pulse-generator"
last_updated: "2026-06-28T02:29:23.930Z"
---

A **shock-pulse generator (SPG)** — most commonly the **Valmet SPG** — generates high-energy gas-detonation shock waves inside a [recovery boiler](/glossary/recovery-boiler) for periodic deep cleaning of [superheater](/glossary/superheater) and [generating-bank](/glossary/generating-bank) deposits. The technology shares its physical principle with [detonation cleaning](/glossary/detonation-cleaning) but is specifically engineered for kraft-recovery-boiler service.

## Where SPG fits

- Recovery-boiler superheater (high-value, deep cavities)
- Recovery-boiler generating bank
- Some industrial-boiler convective passes

The SPG is positioned as a complement to existing [IK long-retract sootblowers](/glossary/ik-long-retract-sootblower), extending intervals between [chill-and-blow](/glossary/chill-and-blow) campaigns by handling consolidated deposits that sootblowers cannot dislodge.

## Position relative to sonic horns

[Sonic horns](/glossary/sonic-horn) work *before* deposits consolidate — they keep ash friable so it can be dislodged by mild cleaning. SPG works *after* consolidation — it breaks hardened deposits that sonic horns could not have prevented. The two technologies operate at opposite ends of the same fouling cycle and are complementary rather than competitive.

## Related terms

- [Detonation cleaning](/glossary/detonation-cleaning)
- [Recovery boiler](/glossary/recovery-boiler)
- [Superheater](/glossary/superheater)
- [Sonic horn](/glossary/sonic-horn)