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Brand: Donaldson
Donaldson HRS-L+ 1000-8750 Closed-Loop Adsorption Dryer
Description
A large heat-regenerated dryer with a closed-loop cooling circuit
The Donaldson Ultradryer HRS-L+ 1000-8750 is the large-flow member of the Ultradryer family, with ten sizes from 1,000 to 8,750 m3/h. Its distinguishing feature is closed-loop cooling during regeneration, which lets it reach a pressure dew point of -70 C at 7 bar(g) (or -40 C) even where the plant ambient air is warm and humid.
Like the other heat-regenerated models it uses ambient air for heating and runs a six-hour cycle under Ultraconomy dew point control. Carbon steel vessels, flanged main pipes and a Siemens S7-1215C controller with KTP700 display are standard.
Technical specifications
| Parameter | Specification |
|---|---|
| Size range | Twelve models, HRS-L+ 1000 up to HRS-L+ 8750 |
| Rated flow | 1,000 to 8,750 m3/h referred to 1 bar and 20 C |
| Pressure dew point | -70 C (or -40 C) at 7 bar(g) |
| Rated condition | 7 bar(g) with saturated inlet air at 25 C for the -70 C class, 35 C for the -40 C class |
| Desiccant regeneration | Room-air heating, then a sealed closed-loop cooling circuit |
| Operating temperature | +5 C to +30 C for -70 C dew point; +5 C to +35 C for -40 C |
| Ambient temperature | +5 C to +40 C |
| Thermal design range | Minus 10 C to plus 230 C |
| Pressure rating | 11 bar(g) vessels to size 2750, PN 16 flanged 10 bar(g) pipes |
| Electrics | Three phase 400 V 50 Hz, S7-1215C with KTP700 screen |
| Line pressure | 4 to 10 bar(g) |
Size table
- 1000: Air volume m3/h 1,000; Flange DN 80; Electrical load kW 18.5; Pressure drop mbar 110
- 1950: Air volume m3/h 1,950; Flange DN 100; Electrical load kW 32.5; Pressure drop mbar 120
- 2750: Air volume m3/h 2,750; Flange DN 100; Electrical load kW 42.5; Pressure drop mbar 180
- 4000: Air volume m3/h 4,000; Flange DN 150; Electrical load kW 67.5; Pressure drop mbar 80
- 6000: Air volume m3/h 6,000; Flange DN 150; Electrical load kW 86.0; Pressure drop mbar 100
- 7000: Air volume m3/h 7,000; Flange DN 180; Electrical load kW 95.0; Pressure drop mbar 120
- 8750: Air volume m3/h 8,750; Flange DN 200; Electrical load kW 115.0; Pressure drop mbar 80
Both inlet and outlet are on the back of the dryer for all HRS-L+ sizes.
Where closed-loop cooling pays off
In open ambient-air cooling the blower air needs to be cool and dry enough to take the heat out of the bed; the sheet states a limit of 35 C at 45 percent relative humidity down to 30 C at 60 percent. Closed-loop cooling is the answer for the -70 C duty and for sites with a demanding climate, which is why the printed operating inlet temperature is limited to 30 C for the deepest dew point.
Donaldson names industrial machinery, food processing, electronics and automotive as industries. Verify the dew point class (-40 C or -70 C), the inlet temperature and the available electrical supply against the sheet before specifying a size. As on the other Ultradryers, the controller offers a potential-free alarm contact, a remote on/off contact and a main switch as standard, and the sheet lists options such as ENERSAVE, vessel insulation, flow and energy monitoring and Modbus or Profibus data links. The dryer is meant for indoor installation, and the adsorber vessels are designed and tested to EN 13445 under the Pressure Equipment Directive.
Documents and quotation
Interested in HRS-L+ 1000-8750? Send the full code and quantity. Please confirm the dew point class, inlet temperature and electrical supply using Donaldson Ultradryer HRS-L+ 1000-8750 data sheet (F119012, 11/2025), attached to the page. Related: Compressors.
Datasheets & Documents
- Datasheet Donaldson Ultradryer HRS-L+ 1000-8750 data sheet (F119012, 11/2025) Download
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About brand
Donaldson is the American filtration company founded in Minnesota in 1915. It started when Frank Donaldson Sr. built an air cleaner for a tractor engine that kept failing in dusty fields. It is now headquartered in Bloomington, Minnesota, and makes filters and filtration systems for engines, hydraulics, compressed air and gases, dust collection and process liquids.
Seven Star LLC is an independent supplier in Muscat. We list Donaldson compressed air dryers and filters, gas filter housings, activated carbon adsorbers, hydraulic and fuel filtration and dust collectors, and supply them and their replacement elements in Oman and the GCC.
Donaldson company profile
| Established | 1915, Minnesota, USA, by Frank Donaldson Sr. and his family |
|---|---|
| First product | An air cleaner for tractor engines |
| Headquarters | Bloomington, Minnesota |
| Product families | Engine air and fuel filters, hydraulic and lube filters, compressed air and gas filters and dryers, dust collectors, process and sterile filtration |
Milestones
- 1915: Frank Donaldson Sr. builds an air cleaner for a tractor that kept failing in a dusty field; the family starts Donaldson Company in Minnesota.
- 1917: Air cleaners are supplied for artillery tractors.
- 1920s: Exhaust products are added after crop fires caused by engine sparks.
- 1974: Donaldson acquires Torit, the dust collector business.
- 2015: The company marks its 100th year.
Donaldson products we list
| Family | Models | Typical use |
|---|---|---|
| Compressed air filters and drains | DF Ultra-Filter, DF-T three-stage, DF-C cyclone, UFM-P drain | Removing water, oil and particles from compressed air |
| Adsorption and refrigeration dryers | Ultrapac HL, HRE+, HRS+, HRS-L+, HLP, Buran, Bora, HRC-T hydrogen | Instrument air with a low dew point, high-pressure air and gas drying |
| Activated carbon and breathing air | Ultrasorp AKC, Ultrasorp Smart, Ultrapure ALG breathing air, A element, AK element | Removing oil vapour and odours for food, pharma and breathing air |
| Gas filter housings | EG (ATEX), HD high-pressure | Process gases and high-pressure gas filtration |
| Hydraulic and fuel filtration | FLK, HNK Duramax, filter cart, Filter Buddy, T.R.A.P. breather, P568583, P574958, AG1398001 skid | Cleaning hydraulic oil and bulk fuel and keeping moisture out of tanks |
| Dust collection | DCE 125 B bin vent | Silo and bin venting for cement, powders and bulk solids |
Compressed air quality is set by ISO 8573-1 classes for particles, water and oil. A typical instrument air system uses a coarse filter and a fine coalescing filter before the dryer, an adsorption dryer for a low pressure dew point (for example -40 °C), and a dust filter after it. An activated carbon stage removes oil vapour where the air touches food or is breathed. Heatless dryers use some of the dry air to regenerate the desiccant, while heat-regenerated and zero-purge types save that air on larger systems.
Where Donaldson products are used
In Oman and the GCC, Donaldson filters and dryers are used for instrument and plant air in oil and gas, refining, power and desalination plants, for breathing air, in food and pharmaceutical production, on hydraulic systems and fuel storage, and in cement and bulk handling.
Ordering Donaldson products: what we need
Send the model and size from the nameplate. For dryers and filters, add the flow (m³/h or scfm), working pressure, inlet temperature, required dew point or ISO 8573-1 class, and the supply voltage. For replacement elements, send the element part number or the housing model.
Facts checked against Donaldson company history, October 2026.
Browse Donaldson products by category: Compressors, Filter Housings, Filtration Systems, Filtration Elements.
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Frequently Asked Questions
What dew point can HRS-L+ reach?
-70 C pressure dew point at 7 bar(g) with a 25 C inlet, or -40 C with a 35 C inlet.
How large is the range?
From HRS-L+ 1000 at 1,000 m3/h to HRS-L+ 8750 at 8,750 m3/h.
What is closed-loop cooling?
The cooling air circulates in a closed loop instead of being drawn from the room, so the dew point holds even at high ambient temperature and humidity.
Which pressure range applies?
4 to 10 bar(g), for compressed air or nitrogen.
How is it controlled?
By a Siemens S7-1215C PLC with a KTP700 touch display and Ultraconomy dew point control.
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