Used Boiler Tube for sale (2,505)

Condition: excellent (used), Year of construction: 2022, functionality: fully functional, operating hours: 60 h, power: 11.5 kW (15.64 HP), input voltage: 192 V, input current: 60 A, temperature: 1,350 °C, inner dimension length: 1,500 mm, inner dimension width: 100 mm, inner dimension height: 100 mm, total length: 2,000 mm, total width: 600 mm, total height: 600 mm, overall weight: 150 kg, number of chambers: 1, actuation type: electric, fuel type: electric, year of last overhaul: 2025, Equipment: CE marking, documentation/manual, Carbolite Gero Tube Furnace – 1350 °C, Ø 100 mm, Length 1500 mm – Fully Functional For sale is a high-quality tube furnace from Carbolite Gero in excellent technical condition. The furnace has only been operated for approx. 200 hours and was primarily used for sintering copper at around 1000 °C. Thanks to the maximum temperature rating of 1350 °C, the system was never thermally overstressed and therefore remains in well-maintained condition. 🔧 Technical Specifications - Max. temperature: 1350 °C - Tube diameter: 100 mm - Tube length: 1500 mm - Temperature measurement: internal thermocouple → precise process control - Features: water-cooled flanges 🔩 Condition & Notes - Furnace is fully operational - Supplied ceramic tube shows signs of previous use Pjdpfx Ahsy H E Ndsyjgk Recommendation: - Replace with new ceramic tube for high-temperature applications - Alternatively, use cost-effective metal tubes for operations below 1100 °C 💡 Benefits - Highly accurate temperature control via internal measurement (i.e., furnace temperature and ramps are regulated by an internal thermocouple, ensuring optimal sample temperature) - Ideal for precise sintering processes, heat treatment, and materials development - Robust industrial design from a reputable manufacturer 📦 Areas of Application - Metallurgy (e.g. copper, steel, ceramics, glass-ceramics, powder metallurgy) - Research & Development - Laboratory and small-scale production applications 🚚 Other - Inspection possible by appointment - Collection only

Condition: reconditioned (used), Year of construction: 2017, functionality: fully functional, operating pressure: 180 bar, empty load weight: 195 kg, input voltage: 400 V, warranty duration: 6 months, temperature: 150 °C, NILFISK MH 7P - 180/1260 FA HOT WATER WASHER NEW HEATING BOILER Manufactured in 2017 Podpfx Asymmgcohyogk The device features new accessories, including a German R+M gun, stainless steel lance, steel braided hose, and a 25° power nozzle. A durable brass head with new ceramic pistons and seals guarantees long and trouble-free operation. A highly efficient three-phase motor ensures stable operation even during prolonged use. With operating parameters of 180 bar and up to 1170 l/h, the machine can be effectively used for heavy-duty work in construction, logistics, and agriculture. Each device we offer has individually taken photos; you are buying exactly what you see. TECHNICAL DATA: Power supply voltage [V]: 400 ~ 3 phase Flow rate [l/h]: 1170 Max pumping capacity [l/h]: 1260 Working pressure [bar]: 180 Maximum pressure [bar]: 250 Max. Heating temperature [°C]: 90-150 Connection power [kW]: 7.6 Detergent tank [l]: 10+10 Hose length [m]: 10 Weight [kg]: 195 EQUIPMENT: NEW HEATING BOILER NEW durable pressure gun from the German brand R+M NEW stainless steel pressure lance NEW reinforced 10m steel braided pressure hose NEW 25° power nozzle WATER FILTER AND GEKA CLAW COUPLINGS - FREE KEY FEATURES: Open oil system - no operating time limits Built-in chemical tank allows for dosing of cleaning fluid directly through the machine Very clear and intuitive control panel Simple design and easy access to individual components under the housing make the machine user-friendly and easy to service

Condition: used, 1 piece metal circular saw PEDRAZZOLI on pallet Color: as shown in the pictures and upon inspection Condition: used Storage location: warehouse hall Payment method: advance payment by bank transfer Pedjy D I U Djpfx Ahyogk Shipping: collection only from the Ditzingen-Heimerdingen location

Condition: ready for operation (used), Year of construction: 2010, laser power: 3,600 W, travel distance X-axis: 6,500 mm, number of axes: 5, This TRUMPF TruLaser Tube 7000 KT02 was manufactured in 2010. It features a working area of 6500 mm on the X-axis and can handle circular diameters up to 200 mm. Equipped with a CO₂ laser TruFlow 2000 and a laser cutting head with a 155 mm lens, it's ideal for precise tube cutting. Contact us for more information about this machine. Pgjdpfxox D I H Ds Ahysk • Circular diameter: 200 mm • Reject station: 3 m with brush table • Reject tray • Process/software features: NoLine, PowerLine, ContourLine, Laser power control, Programmable cutting pressure, Program repeat, Automatic blow-off, Work interruption lighting, Hole-punching function (laser) • Laser: CO₂ laser TruFlow 2000 • Laser cooling unit • Cutting head: Laser cutting head with 155 mm lens • Control unit: 84D • Connectivity/data transfer: RJ-45 network connection, USB connection; network connection incl. installation • Safety: CE marking, Multi-beam light barriers, Capacitor power 1600 N/cm², Safety with macro stops Additional equipment • Accessories: • Spare parts case for cutting heads • 1 x remote control kit • Clamping jaw set Ø 216 / 200 mm • U-shaped guide rails for reject station with ID = 200 mm • Automation: • LoadMaster Tube 6 m with belt support, 2 grippers • Options for LoadMaster Tube 6 m: • Circular diameter 250 mm • Shorter belt support • Swivelable conveyor section • Additional gripper Ø 200 mm • Additional gripper Ø 250 mm • Special equipment: • Flexible reject station 4.5 m (prototype) instead of reject station 3 m, without brush table • Special installation for flexible reject station • LoadMaster (series version 103) • Installation 100 mm higher (use of wire mesh container possible), decision upon acceptance • Services: • Installation, commissioning, training

Condition: good (used), Year of construction: 1992, Manufacturer - ERW Year - 1992 Range of round pipe - 21 - 76 mm Range of square pipe - 20x20 - 60x60 mm Sheet thickness - 0,8 - 3,5 mm Speed - 60 m/min. Lenght of line - 50 m Tools : square pipes - 25,32,38mm round pipes - 40, 51 mm Welding power - 180 KW Pgsdpfx Aedlqkqehyjk Anode voltage - 14 kv Anode dissipation - 70 kw Frequency - up to 30 Mhz

Condition: ready for operation (used), Year of construction: 2005, - USED - TUBE BENDING MACHINE AXIS: 3 MAX TUBE DIAMETER: 30X2 mm WORKING LENGHT: 3000 mm X-AXIS POSITIONING SPEED: 900 mm/sec Y-AXIS BENDING SPEED: 200 °/sec Pedpfxevhc Uus Ahysgk Z-AXIS ROTATION SPEED: 360 °/sec MAX BENDING RADIUS: 20 A 170 mm CONTROL UNIT: DNC800

Condition: used, 🔥 For Sale: Fröling P4 3–15 kW Pellet Boiler – Fully Automatic and Silent for Residential Buildings 🔥 The Fröling P4 3–15 kW is a high-quality, fully automatic pellet boiler – ideal for modern homes, passive houses, and well-insulated buildings. It offers whisper-quiet operation, minimal maintenance, and outstanding energy efficiency. ⸻ Key Features: 🌾 Fuel: Wood pellets ⚡ Output: 3–15 kW 🧠 Fully automatic feeding, ignition, and cleaning 🔧 Integrated control, low-noise operation 🇦🇹 Fröling – Premium pellet technology from Austria 📍 Location: Hungary, 9200 Mosonmagyaróvár, Kötöttárugyári út 22 (ProfiKazán) ⸻ 💼 Top Heating Systems – ProfiKazán Efficient heating solutions for low-energy buildings. TOP HEATING SYSTEMS – Used heating systems, boilers, heat pumps & accessories directly from stock We are a family-run business with around 20 years of experience in heating technology, operating a 1,500 m² warehouse in Mosonmagyaróvár, Hungary, with a continuously available stock of approximately 50–60 units. 📍 Location: Pgodpfxewah Sbs Ahyek Our warehouse is located in Mosonmagyaróvár, Hungary – about 15 km from the Austrian border and approx. 80 km from Vienna. Mosonmagyaróvár is the first major town on the Hungarian side after the Austrian border. 🔥 Our range includes, among others: • Wood chip boilers • Pellet boilers • Wood gasification boilers • Log wood boilers • Biomass boilers • Oil and gas boilers • Heat pumps • Thermo ventilators • Hot air blowers • Warm air heaters • Industrial heaters • Buffer tanks • Heat exchangers • Screw conveyors • Automatic fuel extraction systems • Burners • Pumps • Comprehensive heating accessories ⚙️ Accessories and Components: In addition, we offer a wide range of accessories, including circulation pumps, plate heat exchangers, and many other components – covering both private and industrial applications. 🏭 Brands in our portfolio: Fröling, Hargassner, KWB, HDG, Binder, ETA, Herz, Guntamatic, Windhager, Viessmann, Buderus, and many more. 🌐 Current offers: Most of our current stock can be found on our website: topheatingsystems.com We also have further units available that are not yet listed online. 📅 Inspection: Visits to our warehouse are possible by prior arrangement. If you are interested, please feel free to contact us – we are happy to help you find the right solution.

Condition: excellent (used), Year of construction: 2019, operating hours: 34 h, functionality: fully functional, pressure: 12 bar, operating pressure: 20 bar, temperature: 191 °C, operating temperature: 20 °C, nominal heat output: 579 kW (787.22 HP), Manufacturing Year/ Rok produkcji: 2019 Working Pressure: 12 bar Gas Burner/ Palnik Gazowy Performance/ Wydajność: 850 kg/h Max. steam temprature/ Maksymalna temperatura pary: 191,7°C Run Hours/ Ilość godzin przepracowanych: 34 R/h Pgodpfeygvp Hsx Ahyjk Full Techincal Documentation / Pełna dokumentacja techniczna. Documentation ready to be filed to UDT/ Dokumentacja przygotowana do zgłoszenia do UDT Offer includes extra stainless steel set of chimneys/ Oferta uwzględnia zestaw kominów ze stali nierdzewnej Full installation equipment & armature / Pełny osprzęt do instalacji i armatura

Year of construction: 2017, condition: used, Serial No. 15-6139B, CNC control with touch display, indexing feed conveyor, robot by Yaskawa, type YR-MH00012-A00, year 2011, robot controller DX200, Teach-in terminal, box unloading section, L 7,000 mm, switch/control cabinets, plexiglass enclosure, peripheral units, machine accessories. Subject to prior sale. Pedpfxjy A In Us Ahyegk

Year of construction: 2016, condition: used, Serial no. 15-3599B, primarily comprising: feed station with 2 product lines, continuous cycle conveyor, 2 forming stations, turning station, micro-lubrication station, through-feed washing machine, Manufacturer: Bous, Model: Duwamat K1000 WSST, Year: 2016, Serial no. 2800, 3 tanks, tank capacities: 485/485/715 l, heating capacity 16–24°, fine filter, oil separator, control cabinets, system control with operator panel, Manufacturer: Siemens, Model: SIMATIC HMI touch, inspection system with 2 cameras, Manufacturer: KEYENCE, Model: Vision System, eddy current testing device, Manufacturer: Rohmann, Model: Elotest IS500, laser marking system, Manufacturer: Videojet, Model: 7510, fiber laser, laser power 50 W, discharge station, roller conveyor system for crate removal, 2 product lines, satellite terminals, switch cabinets, safety devices, plexiglass enclosure, peripheral units, including extraction system, Manufacturer: ESTA, Model: Whispersog 2.2 JET, overnut feeder with loading bunker, vibrating bowl feeder, separation unit, loading station, set of trolleys, set of load carriers, trolleys. Subject to prior sale. Pgedey A Ih Uepfx Ahyek

Condition: good (used), Year of construction: 2008, control type: CNC control, pipe diameter (max.): 30 mm, Stainless steel tube diameter: up to 42 x 2.0 mm Steel tube diameter: up to 42 x 3.0 mm Max. bending angle: +/- 180 + 10° Section modulus: 4.1 ccm Operating pressure: 6 bar Total power requirement: 5.5 kW Machine weight approx.: 3 t Space requirement approx.: 6100 x 2300 x 1300 mm Psdpfoy Enmpjx Ahyegk

Condition: good (used), Year of construction: 2002, received a new control unit in 2019 for €14,000 max. bending diameter: 63.5 mm Podoykl Rzjpfx Ahyjgk smallest bending radius: 32 mm motor: 30 kW

Condition: good (used), Year of construction: 1994, Heating boiler for hot water or steam. Fuel: wood chips. Heating capacity: 6 MW. Up to 120°C, permissible overpressure: 1 bar. Can also be operated with an oil burner as fuel. Dismantling must be carried out by the buyer. Pjdoyiky Aepfx Ahyogk

Condition: good (used), Year of construction: 2013, Wood chip boiler for steam up to 150°C or just water Max. thermal output up to 850 kW Suitable for dry material Pgsdpfx Ahey Dfd Njyjk

Condition: good (used), functionality: fully functional, Year of construction: 2020, machine/vehicle number: 2020130, control type: CNC control, degree of automation: automatic, actuation type: electric, controller manufacturer: Cypcut, laser type: fiber laser, laser source manufacturer: IPG, laser power: 2,000 W, laser wavelength: 1,070 nm, sheet thickness (max.): 15 mm, sheet thickness steel (max.): 15 mm, pipe diameter (max.): 220 mm, pipe length (max.): 6,000 mm, working length: 6,000 mm, travel distance X-axis: 6,050 mm, travel distance Y-axis: 220 mm, travel distance Z-axis: 150 mm, feed rate X-axis: 30 m/min, feed rate Y-axis: 30 m/min, cutting speed: 13,000 mm/min, positioning speed: 80 m/min, positioning accuracy: 0.05 mm, repeat accuracy: 0.03 mm, power: 26.5 kW (36.03 HP), input voltage: 400 V, input frequency: 50 Hz, overall weight: 5,000 kg, Equipment: documentation/manual, dust extraction, fume extraction, CYPCUT - CYPTUBE, auto-center positioning, pneumatic clamping, automatic alignment device, automatic clamping device, cutting head incl. protective glass, Raytool / SWISS, laser source - IPG / Germany, software for 3D tube and profile cutting, automatic loading system for tubes and profiles, extraction unit Filtercube 2H, 4 kW, 50 m² Pgsdoy Efbkspfx Ahysk

Condition: used, functionality: fully functional, Year of construction: 2005, control type: CNC control, degree of automation: automatic, actuation type: hydraulic, pipe diameter (max.): 250 mm, pipe length (max.): 6,000 mm, power: 60 kW (81.58 HP), input voltage: 400 V, Equipment: cooling unit, emergency stop, For sale: TRUMPF TUBEMATIC Tube Laser Cutting Machine – Fully Equipped. The machine was used in industrial production and is in full working condition. Professionally dismantled and preserved in complete configuration. Scope of supply: - Bed and mechanical components - Electrical cabinets with original TRUMPF electronics - Drives, control units, power modules - Cooling system (chiller) - Cable tracks, sensors, wiring, etc. Machine technical specifications: X-axis travel: 6500 mm Y-axis travel: 200 mm Z-axis travel: 150 mm Workpiece sizes: Stock length * For manual loading: 141–6500 mm * For automatic loading: 3000–6500 mm Max. finished part length: 2000 mm Min. tube remnant length: 141 mm Wall thickness: 0.8–6.4 mm Round tube dimensions: Ø20–Ø150 mm Square profile dimensions: 20x20–120x120 mm Rectangular profile dimensions: 20x20 – max. oval Ø150 mm Workpiece weight: Max. workpiece weight: 120 kg Max. workpiece weight for unloading station: 40 kg Max. bundle weight: 4000 kg Speeds: X-axis: 100 m/min Y-axis: 40 m/min Z-axis: 40 m/min A-axis: 720 º/s Positioning accuracy1: Position deviation: ±0.2 mm Pedpfx Aeyfnblohysgk Average range deviation: ±0.06 mm According to VDI / DGQ 3441, the measured length is 1 m. Processing accuracy depends on material type, its preprocessing, dimensions, and position in the working area. Control system: CNC TRUMPF – Siemens Sinumerik 840 D Total weight of the basic machine configuration: 15,460 kg Laser data: TRUMPF TLF CO₂ laser with high-frequency excitation – TLF 2000 Guaranteed max. laser power (programmable in 1% steps): 2000 W Pulse repetition rate: TEM00 Gas consumption: Laser gases *CO₂ – 1 l/h *N₂ – 6 l/h *He – 13 l/h Cutting gases *O₂ – depending on application *N₂ – depending on application Laser cooling: closed circuit Maximum power requirement for full system: 63 kW/h Pneumatic connection: 7–10 bar

Year of construction: 1999, operating hours: 76,000 h, condition: used, functionality: unexamined, Technical parameters: • Manufacturer: AUSTRIAN ENERGY Pjdpfjy D Hy Ejx Ahyjgk • Type: Dual pressure drum boiler (1999) • HP steam flow: t/h 40.8 • LP steam flow: t/h 17.3 • HP steam parameters: bar/°C 52 / 425 • LP steam parameters: bar/°C 4.2 / 180 • Flue gas temperature at HRSG outlet: °C 80 • Flue gas stream to the stack: t/h 468, k Nm3/h 482 • Heat recovered by the steam and water cycle from flue gas in HRSG: MWt 45.9 • Maximum output of DH exchanger: MWt 8.0 • Operating hours: 76,000 hours The high- and low-pressure sections of the equipment and the drums (HP and LP) consist of 6 independent, transportable modules. The boiler wall insulation is partial and requires replacement.

Condition: ready for operation (used), GASTEC Detector Tubes indicate concentrations directly by way of a calibrated scale printed on the tubes. At GASTEC, we endeavour to achieve highest quality detector tubes for analysing airborne gases/vapours, as well as pollutants in soil and water through our advanced state-of-the-art research and development. Through our efforts we have acquired a solid reputation among our customers in virtually all sectors of industry, commerce and society. Tubes are now available for more than 500 different applications. Psdpfx Ajy D D Tcohyjgk

Condition: like new (used), Year of construction: 2008, functionality: fully functional, operating pressure: 13 bar, operating temperature: 195 °C, empty load weight: 800 kg, JUMAG DG 360 Steam Generator, Made in Germany. Regarded by specialists as the best steam generator in the world. Coil-less design. Equipped with a water jacket. Delivers consistent and smooth steam output, without pressure or temperature fluctuations or surges. Performance – 360 to 400 kg/h. The generator features two power ranges: 1st stage up to 200 kg/h; 2nd stage with modulation up to 400 kg/h. Operating pressure from 6 bar up to a maximum of 13 bar. Fuel – oil/gas. Economizer. Automatic or manual blowdown. Complete documentation. Commissioning warranty. Psdpfx Aheyfihtsyjgk Boiler inspected and pressure tested. Demonstration and commissioning available on-site or via video. Equipped with Grundfos feed pump and safety valve. EXCELLENT CONDITION. Serviced by "ZAG" Jumag Switzerland. Complete documentation for UDT (Office of Technical Inspection) registration. All machines offered by us undergo rigorous technical inspections, including pressure tests, safety automation system checks, leak tests, and more. We cooperate with a logistics company that delivers our equipment to clients across Europe and beyond.

Condition: used, Year of construction: 2010, functionality: fully functional, - Brand: Bongard - Model: Cervap 600 / 9 doors - Technology: steam tube - Energy: gas or fuel oil - Configuration: 3 decks - Number of lanes: 3 lanes - Lane width: 600 mm - Total number of doors: 9 - Usable height per deck: 170 mm - Application: bakery - Application: pastry - Application: viennoiserie - Baking by conduction - Baking by radiation Pgodsy Duyaspfx Ahyok - Annular steam tubes - Refractory stainless steel combustion chamber - Steam generator per deck - Standard control: Ergocom - This is a professional bakery oven from the French brand Bongard. It is a model from the Cervap range.

Condition: new, functionality: fully functional, Year of construction: 2025, operating hours: 1 h, control type: CNC control, degree of automation: automatic, actuation type: hydraulic, tube wall thickness (max.): 2 mm, bending radius (min.): 90 mm, number of axes: 3, total length: 5,500 mm, total width: 1,600 mm, total height: 1,600 mm, warranty duration: 12 months, Equipment: CE marking, emergency stop, foot remote control, 3 Axis 65 CNC Mandrel Tube Bending Machine TROX Liv Makina's most powerful machine is the CNC mandrel tube bending machine capable of bending tubes and profiles up to 65 mm with 3 axes, suitable for bending jobs in the Shipbuilding Industry, Thermal Power Plants, Park and Garden Furniture, Fitness Equipment, and Exhaust Industry sectors. What is difficult becomes easy thanks to hydraulic bending.  Ability to import drawings via Solidworks Program  Operation in fully automatic or manual modes via interactive PLC control system  Multiple language options  Ability to view products in 3D Podpfxey Dpgze Ahysgk  3D pipe collision simulation  Automatic pipe length calculation  Conforms to CE norms  Ability to see errors on display  Safety warning system  Easy usability thanks to Livmak Interface Technical Specifications – TROX 3Axis 65 CNC Max Bending Capacity: Ø65 mm x 2 mm Min/Max Mold Diameter: 90/250 mm Material Processing Length: 4000 mm Machine Dimensions: 5500x1750x1750 mm Total Motor Power: 15 Hp Machine Weight: 3 Tons

Condition: new, functionality: fully functional, Year of construction: 2025, operating hours: 1 h, control type: CNC control, degree of automation: automatic, actuation type: electric, tube wall thickness (max.): 2 mm, bending radius (min.): 60 mm, number of axes: 5, working height: 1,500 mm, overall weight: 2,700 kg, total length: 5,500 mm, total width: 1,800 mm, total height: 1,800 mm, warranty duration: 12 months, Equipment: CE marking, emergency stop, foot remote control, 5 Axis 38 CNC Mandrel Tube Bending Machine PUMA Liv Makina’s 5-axis 38 mm CNC mandrel tube bending machine is one of the company’s models with the highest number of references spanning four continents in the Automotive, White Goods, and Defense Industry sectors. Its Solidworks-compatible interface ensures highly user-friendly operation. Our Industry 4.0-compliant machine provides daily reporting directly to your team. Thanks to its rolling die, the machine is capable of coiling tubes like a spring. Its feature of accommodating dies with 3 different radii makes even the most challenging bends much easier. The collision simulation software, which allows users to preview the bending process on-screen and helps save time, is provided free of charge on all of our CNC tube and profile bending machines. Pgodpfx Ahey Dpgneyjk  Ability to import drawings to the machine via Solidworks  Fully automatic and manual operation modes with interactive PLC control system  Multiple language options  3D program visualization  3D pipe collision simulation visualization  Automatic tube length calculation  Compliant with CE standards  Error display on screen  Safety warning system  Easy operation via the Livmak interface Technical Specifications – PUMA 5 Axis 38 CNC Max Bending Capacity: Ø38 mm x 2 mm Min/Max Die Diameter: 60/250 mm Material Processing Length: 4000 mm Machine Dimensions: 5500x1600x1600 mm Total Motor Power: 15 Hp Machine Weight: 2.5 tons

Condition: used, We offer Viessmann natural gas boilers: 1. Viessmann gas boiler TYPE SX 1 Heating output 225 kW Including pump and valves 2. Viessmann gas boiler TYPE SX 1 Heating output 170 kW Including pump, valves, and piping Pjdpfx Aoy Dpk Hshyogk You will receive a discount when purchasing both boilers. The boilers will be ready for operation by the end of May 2026.

Condition: used, functionality: fully functional, Year of construction: 2021, operating hours: 17,958 h, machine/vehicle number: 0752101130704, degree of automation: automatic, pipe diameter (max.): 152 mm, power: 21 kW (28.55 HP), input voltage: 380 V, input frequency: 50 Hz, type of input current: three-phase, overall weight: 10,000 kg, We offer this used BLM LT FIBER EVO TUBE LASER laser cutting machine, year of construction 2021 with a 3kW fiber laser source. It has high-speed precise cutting and an integrated loading and unloading system. Suitable for steel, stainless steel and aluminium. It can cut complex shapes and profiles. Available for inspection and ready for immediate sale. Must be seen. Pjdpfx Ahjyui Ekeysgk Serial number: 0752101130704 Manufacture date: 10/2021 Supply voltage: 380 V Phases: 3 Supply frequency: 50 Hz Total installed power: 21 kVA Interrupting capacity: 25 kA Control voltage 1: 24 V Control voltage 1 type: DC Control voltage 2: 220 V Control voltage 2 frequency: 50 Hz Weight: 10000 kg If you have any questions or need more information, feel free to send us a message or give us a call.

Condition: excellent (used), Buderus kB 372-250kw condensing boiler 100°6Bar Pgsdpfsvyvhfjx Ahyok