Air Blower Manufacturer & Supplier from China
Energy-Saving Roots Blower & Roots Vacuum Pump
The LC series is Slovdson’s line of energy-saving roots blower vacuum pumps — five main power ratings from 15 kW to 45 kW built on a single platform, each capable of operating as a pressure blower or a vacuum pump from the same machine. What makes them “energy-saving” is the drive system: a permanent magnet synchronous motor (PMSM) paired with a variable frequency drive (VFD) replaces the fixed-speed induction motor found on conventional roots blowers, – the result is: 30 to 65 percent less electricity consumption, year after year.
Table of Contents
A Replacement for Conventional Roots Blower and Roots Vacuum Pump
We are increasingly replacing the classic Longtech roots blowers and roots vacuum pumps with this upgraded Roots Blower & Vacuum Pump for tissue paper converting factories and wastewater treatment applications. If you are concerned about lower noise and higher efficiency, here is the machine you need.
LC series · permanent magnet drive
Energy-saving Roots Blower &
Roots Vacuum Pump
One machine. Two jobs. Air Blow or Vacuum Pump.
- Dual function
Same host runs as pressure blower or vacuum pump. No second machine to buy or service. - Rare-earth PMSM
Permanent magnet synchronous motor. 186 N-m torque, no rotor windings, no resistive heat loss. - High-efficiency VFD
Holds constant pressure or vacuum, soft start and automatic load matching.
30-65%
Less energy than fixed-speed blowers
8-13 dB
Quieter than conventional roots blowers
Watch more videos on the Slovdson YouTube Channel.
One Platform, Two Modes: Roots Blower & Vacuum Pump
Every LC series machine is a dual-mode host. The three-lobe rotors, dual-gearbox, PMSM motor, and VFD are identical in both modes; they are the same machine – roots blower vacuum pump. What changes is which port you connect to your process:
| Pressure Blower Mode | Vacuum Pump Mode | |
|---|---|---|
| How it works | Connect the discharge port → blows pressurized air into a system | Connect the inlet port → pulls air out of a system |
| Typical pressure/vacuum | +10 to +50 kPa (varies by power) | −10 to −50 kPa (varies by power) |
| VFD mode | Constant-pressure — holds target pressure as system resistance shifts | Constant-vacuum — holds target vacuum as filters load and demand changes |
| Top applications | Wastewater aeration, pond oxygenation, pneumatic conveying, combustion air | Tissue paper converting, vacuum packaging, pneumatic vacuum conveying, central vacuum |
| Spare parts | Shared across both modes — same belts, same filters, same oil | Shared across both modes — same belts, same filters, same oil |
💡 One machine, two jobs. If your process needs both pressure and vacuum at different stages, a single LC unit with valved connections handles both — and your spare parts inventory covers both sides.
The majority of LC series units sold to tissue paper manufacturers run in vacuum mode. Power plants, cement works, and wastewater stations typically run in pressure (blower) mode. The machine doesn’t care — same host, same maintenance, same 30–65% energy savings either way.
This page is the overview. For detailed specifications, application guidance, and pricing — pick your power rating:
| Power | Model | Flow | Pressure (Blower) | Vacuum (Pump) | Best For |
|---|---|---|---|---|---|
| 15 kW | SLDS-1500LC → | 30 m³/min | 10–30 kPa | −10 to −30 kPa | Small tissue lines, aquaculture, compact footprint |
| 22 kW | SLDS-2200LC → | 30 m³/min | 20–35 kPa | −20 to −35 kPa | 2–3 tissue machines, general industrial, wastewater |
| 30 kW | SLDS-3000LC → | 30 m³/min | 20–40 kPa | −20 to −40 kPa | 3–4 tissue machines, chemical, high back-pressure |
| 37 kW | SLDS-3700LC → | 31 m³/min | 25–45 kPa | −25 to −45 kPa | 4–6 tissue machines, pneumatic conveying ★ |
| 45 kW | SLDS-4500LC → | 48 m³/min | 30–50 kPa | −30 to −50 kPa | 6–8+ tissue machines, power plants, cement ★ |
★ = Bestselling models for tissue paper manufacturers.
Don’t know which power rating you need? Let us know your required airflow and pressure. Customer support is here for you!
The Engineering Behind the Savings: PMSM Motor + VFD
Every LC series unit — from 15 kW to 45 kW, in both pressure and vacuum mode — runs on the same core drivetrain. This is what makes the whole range “energy-saving,” not any single model.
A conventional roots blower pairs a fixed-speed induction motor with a throttle or bleed valve. It’s cheap to build and wastes electricity at partial load: at 70% load — where most blowers spend the bulk of their operating hours — a typical induction motor drops to roughly 85% efficiency. In contrast, the blower still moves the full air volume and the surplus is dissipated as heat.
The LC series roots blower vacuum pump fixes both problems at the source:
PMSM motor (permanent magnet synchronous).
Rare-earth magnets energize the rotor directly — no rotor windings, no induced current, no I²R rotor losses. Efficiency holds above 93% even at partial load, versus ~85% for an equivalent induction motor. The 186 Nm torque (≈20% higher than class-average) means less belt slip and less speed droop as pressure or vacuum climbs.
VFD (variable frequency drive).
Matches motor speed to actual demand instead of forcing full output. At 50% load, the motor draws roughly 50% of the power. The LC VFD tunes from 45 to 110% of rated capacity with custom drive curves that hold the motor in its peak-efficiency zone across the whole operating envelope — plus soft start (no breaker-tripping current spike) and constant-pressure or constant-vacuum mode.
Additional VFD capabilities:
- Soft start — eliminates the 6–8× inrush that trips breakers on smaller sites.
- Constant-pressure / constant-vacuum mode — set it and the drive holds the setpoint as conditions shift.
- Built-in protection — over-current, phase loss, surge detection.
Why the combination — not either part alone — is the real story.
A VFD only pays off if the motor stays efficient where the VFD runs it: at part load. PMSM delivers exactly that, holding high efficiency in the 45–70% band where a VFD spends most of its time. Pair them and electricity drops 30 to 65% versus a fixed-speed roots blower on the same process.
What You Save: Real Numbers
The 30–65% range spans worst-case (steady full load, high back-pressure) to best-case (variable load, moderate pressure). Most installations land in the 35–50% range.
| Scenario | Power | Annual kWh (Conventional) | Annual kWh (LC) | Annual Savings |
|---|---|---|---|---|
| Tissue mill, 5 folding lines, 18h/day | 37 kW | 213,000 | 117,000–138,000 | $9,000–$14,100 |
| Tissue mill, 7 folding lines, 20h/day | 45 kW | 306,000 | 168,000–199,000 | $12,800–$20,200 |
| Wastewater aeration, 24/7 | 22 kW | 193,000 | 106,000–125,000 | $5,800–$12,500 |
| Aquaculture pond, 12h/day (diesel) | 15 kW | — | — | Diesel savings pay back in <12 months |
At $0.12/kWh. Payback on the LC’s upfront price premium: 18–30 months for grid-connected operations. Faster if your electricity rate is higher or if you run multiple units.
Quick Selection Guide for Roots Blower Vacuum Pump
By Application
| Your Application | Recommended LC Model | Mode | Why |
|---|---|---|---|
| 1 small tissue folding line | 15kW → | Vacuum | Compact footprint, fits single-machine workshops |
| 2–3 tissue folding lines | 22kW → | Vacuum | Industrial sweet spot, covers most small-medium shops |
| 3–4 tissue folding lines, medium-high speed | 30kW → | Vacuum | Extra vacuum depth for facial tissue and higher speeds |
| 4–6 tissue folding lines ★ | 37kW → | Vacuum | Bestselling tissue paper model — deep vacuum, multi-line stability |
| 6–8+ tissue folding lines, high speed ★ | 45kW → | Vacuum | Largest tissue paper model — 48 m³/min, multi-hall capable |
| Small pond aeration, RAS | 15kW → | Pressure | Low noise, oil-free air — won’t kill fish |
| Municipal wastewater (medium) | 22kW → | Pressure | Covers most 2–5m depth aeration basins |
| Industrial wastewater, MBR | 30kW → | Pressure | High back-pressure capability for membrane scouring |
| Pneumatic conveying (batch) | 37kW → | Pressure or Vacuum | Soft-start saves belts on frequent cycling |
| Power plant FGD, cement kiln | 45kW → | Pressure | 48 m³/min, 50 kPa — covers medium-large units |
LC Series vs Classic SL Series: Which Drive System?
| SL / SLV (Classic) | LC Series (Energy-Saving) | |
|---|---|---|
| Motor | Fixed-speed induction motor | PMSM — permanent magnet synchronous motor |
| Speed control | Single speed — runs at full output | VFD — variable frequency drive, 45–110% |
| Energy at 50% load | ~90–95% of full power | ~50% of full power |
| Energy savings | Baseline | 30–65% vs. classic |
| Upfront cost | Lower | Higher — payback in 18–30 months |
| Best when | Intermittent use, steady full load, budget-constrained | 24/7 operation, variable load, high electricity rates |
| Cabinet | Separate motor base + external silencers | Fully integrated — PMSM motor, VFD, silencer, and filtration in one cabinet |
| Noise | 70–105 dB (varies by model) | 68–85 dB (varies by power) — integrated acoustic insulation |
| Available as | Pressure (SL) + Vacuum (SLV) | Pressure + Vacuum — same machine, both modes |
| Product pages | SL Series → / SLV Series → | 15kW · 22kW · 30kW · 37kW · 45kW |
💡 The rule of thumb: If your blower or vacuum pump runs more than 3,000 hours per year with variable load, the LC series typically pays for itself within 18–30 months through electricity savings alone. If it runs intermittently or at steady full load, the SL/SLV series is the more cost-effective choice.
What’s Inside Every LC Series Machine
All five LC power ratings share the same core platform. Each machine is a fully packaged unit — three-lobe CNC-machined rotors, dual-gearbox (rated 18 years), PMSM motor (186 Nm torque, sealed, 93%+ efficiency), belt drive, VFD with dual drive curves (pressure and vacuum modes), 4-chamber resonant silencer with six-sided acoustic insulation, integrated inlet filtration (front-accessible, tool-free), and vibration isolation pads (no anchor bolts required).
Individual power pages cover what changes at each rating — cabinet dimensions, gearbox sizing, and outlet diameter. 15kW · 22kW · 30kW · 37kW · 45kW
Roots Blower Vacuum Pump Applications
Tissue Paper Converting
Tissue paper manufacturers are the largest customer group for the LC series, particularly the 37kW and 45kW models in vacuum mode. Tissue converting lines — producing napkins, facial tissue, and paper towels — use vacuum to transport individual sheets through folding and cutting stations. Vacuum stability is production-critical: a half-second fluctuation means a misfed sheet and a line stop.
The LC’s VFD constant-vacuum mode holds the target vacuum level as inlet filters load with paper dust, as individual folding machines cycle for reel changes, and as ambient conditions shift through the day. No operator intervention. No manual valve throttling. The line doesn’t stop.
Which model for tissue?
- 1–2 folding machines → 15kW or 22kW
- 3–4 folding machines → 30kW
- 4–6 folding machines → 37kW ★ most popular
- 6–8+ folding machines → 45kW ★
Wastewater Treatment
Aeration blowers are typically 40–60% of a treatment plant’s total electricity consumption. The LC series in pressure mode delivers steady airflow for activated sludge basins, MBR membrane scouring, and deep-tank aeration. The VFD’s constant-pressure mode compensates automatically as diffusers foul and back-pressure rises. Variable-speed operation tracks diurnal flow patterns — low output overnight, full output during the daytime peak — saving energy every day without operator involvement.
Aquaculture
Pond aeration is the highest operating cost on shrimp and fish farms. The LC series in pressure mode provides oil-free air — oil mist kills fish and disrupts biofilter microbial communities. For farms running on diesel generators, every kilowatt-hour saved through the VFD’s variable-speed control is fuel not burned. The 15kW and 22kW models are the standard fit for pond aeration and RAS systems.
Pneumatic Conveying
Bulk solids — cement, flour, grain, plastic pellets — move through pipelines on a stream of air. Roots blowers deliver the constant-volume airflow that handles fluctuating material loads without stalling. The LC series serves both pressure conveying (discharge port) and vacuum conveying (inlet port). The VFD’s soft-start is particularly valuable in batch conveying: the pump draws significant current only during the transfer phase, idles at low speed between batches, and restarts without the current spike that shortens belt life on conventional direct-on-line motors.
Power & Cement
Combustion air, flue gas desulfurization, raw meal fluidization, ash handling — these applications run 24/7 at varying loads. The 45kW LC in pressure mode is the standard recommendation for medium-to-large units, with the 37kW covering smaller installations.
Noise Levels: All Models
| Model | Power | Typical Noise (dB) | vs. Conventional |
|---|---|---|---|
| SLDS-1500LC | 15 kW | 68–78 | 7–12 dB quieter |
| SLDS-2200LC | 22 kW | 70–80 | 8–13 dB quieter |
| SLDS-3000LC | 30 kW | 72–82 | 8–13 dB quieter |
| SLDS-3700LC | 37 kW | 74–84 | 8–13 dB quieter |
| SLDS-4500LC | 45 kW | 75–85 | 8–13 dB quieter |
Measured at 1 meter with standard silencers installed. The integrated 4-chamber resonant silencer and full cabinet acoustic insulation account for the reduction. Every 10 dB reduction is perceived as roughly half as loud.
Why Slovdson for Energy-Saving Roots Blowers & Vacuum Pumps
- Manufacturer-direct, not a trading company. Our factory in Ganzhou, Jiangxi handles casting, machining, assembly, and testing under one roof. You buy from the source.
- ISO 9001:2015 certified. Same processes, same quality — every LC machine, every power rating. Also CE certified (3 product categories), RoHS compliant, with 3 utility model patents and 1 industrial design patent.
- 5 power ratings, 2 modes. One supplier covers your full energy-saving roots blower and vacuum pump range — 15 to 45 kW, pressure and vacuum, all on the same PMSM + VFD platform. No need to qualify multiple vendors.
- Tissue paper specialists. The LC series is proven in tissue converting plants across our customer base. We understand paper dust management, multi-line vacuum stability, and the production cost structure of a tissue mill.
- English-speaking engineers. They size blowers and vacuum pumps, read P&IDs, calculate ROI for energy-saving upgrades, and flag issues before you order. Not just order-takers.
- Spare parts ship within 48 hours. Bearings, seals, gaskets, filters, belts — stocked and ready. LC pressure and LC vacuum share parts across all five power ratings.
- OEM and private labeling available. Your brand, our hardware.
Frequently Asked Questions
What makes the LC series “energy-saving” compared to a conventional roots blower?
Two things working together. The PMSM permanent magnet motor maintains 93%+ efficiency across a wide load range, versus ~85% for an induction motor at partial load. The VFD variable frequency drive matches motor speed to actual demand — at 50% load, it draws roughly 50% of the power, whereas a fixed-speed blower still draws near-full current. Together they cut electricity consumption by 30–65%.
Can one LC machine really work as both a pressure blower and a vacuum pump?
Yes. The three-lobe rotor host, dual-gearbox, PMSM motor, and VFD are identical. The only difference is which port you connect to your process. Connect the discharge port → pressure blower. Connect the inlet port → vacuum pump. Same spare parts, same maintenance. Switching between modes means reconnecting the pipe — not replacing the machine.
How do I choose between the five power ratings?
Start with your application (see the Quick Selection Guide → above). If you’re unsure, send us your required flow rate, pressure or vacuum level, and operating hours — we’ll select the right model and calculate your payback. The 37kW and 45kW are our most popular models for tissue paper manufacturers; the 15–30kW cover smaller operations and general industry.
How long until the energy savings pay back the higher upfront cost?
Typically 18–30 months for machines running 16–24 hours/day at industrial electricity rates ($0.10–0.15/kWh). Faster if your electricity rate is higher, if you run multiple units, if you’re displacing diesel generation, or if government energy-efficiency incentives are available. We include a payback calculation specific to your site with every quote.
Is the LC series the right choice over the classic SL series?
If your blower or vacuum pump runs more than 3,000 hours per year with variable load, the LC series typically pays for itself. If it runs intermittently or at steady full load, the SL/SLV series is more cost-effective. See the LC vs SL comparison table above for a detailed breakdown.
How much does an energy-saving roots blower or vacuum pump cost?
LC series pricing depends on the power rating, operating pressure/vacuum, and accessory package. The LC carries a higher upfront price than a conventional roots blower but recovers it through electricity savings. We quote within one working day — send your flow, pressure/vacuum, operating hours, and electricity rate for an exact price with a payback calculation.
Do you ship to my country?
We ship to tissue mills, wastewater plants, aquaculture operations, and industrial facilities across Asia, Africa, the Middle East, and South America. Contact us with your location for shipping options and lead time.