Siphon design calculations

Siphon design calculations. The Gravity Sewer Pipeline Design Page 1 of 5 Latest Revision: March 2020 SECTION 6. Nov 24, 2023 · Thermosiphon Reboiler Design With Calculation and Example. To empty a channel when there is no outlet. Hydraulic design requirements, inlet and outlet distribution rooms features and protection of expected loads on syphons’ pipes were taken 201 Rue Iberville, Suite 115, Lafayette, LA, 70508. The siphon system has a tight design constraint to ensure that the siphon doesn’t trigger prematurely. Material of siphon pipe is FRP and its flow rate is 3,900 m3/hr. Therefore, even if there is only one main sewer pipe, several siphons may be required. Jun 21, 2016 · i have to design an inverted siphon. Figure 5 Pressure vs. Calculation is based on experimental studies that, due to their nature and rigor, cover the siphon breaker devices used in research reactors. 318 if using imperial units, C is the roughness coefficient of the pipe material, R is the hydraulic radius (cross-sectional area divided by perimeter), and S is the slope of the pipe. Flush/clean the invert siphon regularly- twice annually depending on the sediment load. The capacity of siphons is defined by the maximum vacuum at extreme points of the throat cross-section. Example Scenario: Consider a distillation column that requires a thermosiphon reboiler to vaporize 8,000 kg/h of a liquid with a heat of vaporization (Δ H vap ) of 400 kJ/kg. Therefore, this method of determining discharge is approximate but could be useful for estimating Special care must be taken in inverted siphon design since losses are greater for pressurized flow, and the velocity in each siphon pipe must be at least 3 ft/s (0. Provisions should be made to avoid a siphon effect with a pumped system because a siphon in this case may damage the pump. Here’s how it works: as water fills the reservoir, the surface of the water is equally exposed to atmospheric pressure. Filter Inlet Channel with Rectangular Weir Flow Distribution In plants with flow rates large enough to use open stacked rapid sand filters the settled water is delivered to those filters through an open channel. Aug 14, 2011 · The siphon pipe is used for transferring sea water from sea to intake basin in shoreline. This is equilavent to using average daily flow (design flow) with the pipe flowing approximately 40% full. This study focuses on identifying the safest and optimum design of a sewage inverted syphon to avoid intersection problems with immovable infrastructures. 78Z eff, even for optimum Engineering and Design of Siphon Spillways 393 Our inverted siphon calculation allows up to five parallel siphons to go lower the river. When the flush valve is opened water flows from the tank into the bowl, the water level rises, and water begins to flow into the down leg. com. Some limited grading may be required to increase the flow capacity of the ditch, provide for flow Siphon Discharge Rate Calculator . This program is based on the equations and procedures found in the DIPRA brochure Thrust Restraint Design for Ductile Iron Pipe. Drainage Pipe Required (minimum diameter): Thrust Restraint Design for Ductile Iron Pipe. Nov 24, 2017 · The height of the upper leg dictates the static water level in the bowl. hdrinc. To empty a reservoir when there is no outlet. Three-dimensional computational fluid dynamics (CFD) technique using finite-volume method to solve Reynolds-averaged Nov 24, 2020 · Image Courtesy of iStockPhotos. Use Manning Equation or Charts to determine pipe size. 2 Onsite System Design Strategy 4 3 SITE EVALUATION PROCEDURES 3. 486 A R. We recommend digging the sediment basin as deep as practical to allow for maximum storage of sediment and creating a permanent water level within the basin. In Water purification plants. (3) For trouble free working self-cleansing velocities should be provided in the siphon. program to learn first, how our own design performed, then why it, failed occasionally to perform properly, and later, how to develop a new design for an improved siphon spillway. Each chart has been designed for a particular siphon length,representative of the most common lengths provided by manufacturers. While designing the inverted siphon the following points should be considered: (1) Construction of inverted siphon should be simple. A siphon is a bent or curved tube that carries fluid from a fluid surface at a high elevation to another fluid surface at a lower elevation. 013 R = hydraulic radius = cross sectional area wetted perimeter S = slope The Orange County Sanitation District consists of a service area of 471 square miles, including 21 city and three special district member agencies. The siphon, designated as Design 1 (Figure 2-A) was represented by a 1 to 24 scale model constructed from laminated plastic while those -designated as Designs 2 and 3 (Figures 2-B and C) were represented by models of the same scale constructed of sheet metal. 2. Issues related to the design and hydraulic calculation of the transit part of a closed tubular water supply structure of the siphon type is considered. 8 ha (118 ac) pond drainage area, calculations showed an 8-inch siphon would be conservatively sufficient. ic. 2 Disposal Alternati ves 13 3. (76 mm). comparing the energy levels for the fluid at the tank surface to the peak point of siphon) p 1 = 0 N/m 2 (g) z 2 = 1. 13 MB) Riser_Barrel_Hydraulics_with_Coefficients (944. its normal design elevation, resulting in an estimated loss of 1. xls. Unlike the main sewer pipe, the siphon pipe(s) flow under pressure. General provisions are presented for the design and engineering of proven hydraulic designs for siphon spillways. o System capacity required (flow to system) and flow development including: calculations, flow measurement data, and future flow data for the project as well as estimates for future development within the sewer shed based on the best available information o Spreadsheet model or calculations of existing wastewater lines for a minimum of 0. Siphon diameter = 4 cm, The siphon outlet end is 2m below the surface in the tank, T1; The peak point of the summit is 1. Modified Hooke and Jeeves method considered in the present study and some modifications were doing. 63 × S 0. In the present study, the optimum hydraulic and structural design of inverted siphon has been studied. To analyze the characteristics of siphon breaking, a real-scale experiment was conducted. Huadian technology，2012( 12) : 18-20 Thermosiphon (or thermosyphon) is a method of passive heat exchange, based on natural convection, which circulates a fluid without the necessity of a mechanical pump. 21 KB) Rock_Chute_Design (1. a. 6 mm) to 1⁄2 in. Siphons can be installed in virtually any type of tank, basin, or reservoir that holds a fluid. Overall Diagram: Floor view of inlet chamber (3 siphons): Section A-A (exploded scale): Available ease of fabrication, all siphon inverts can be located at the elevation of to lowest siphon invert. 9 KB) PIPELINE_Ver2 (289. In irrigation systems to supply controlled level of water. Calculation sheet of reinforced foundation. (13 mm) to release air under pressure continuously during pipeline operation. 60 m D/s water level= 465. 6. Compute the maximum flow in the main sewer pipe using Manning's equation for full pipe flow. M-616-1 Inverted Siphon. n Where n = . Siphon Quantity Chart The Siphon Quantity Chart is a graphical display of the relationship between pond size and the number of siphons required for one foot of drawdown in 24 hours. Apr 4, 2021 · SIPHON DESIGN • Siphon design allows for single barrel, double barrel or multi barrel and the number of barrels • Design is critical for the future life span of the pipe due to its impact on operations. At the other hand, we have been informed that one plant has operated siphon pipe with maximum proposed by the Design Section for study in the hydraulic model (Figure 2). Oct 27, 2020 · 4. director county of san diego. First sheet provided with formulas for better understanding and another one having simple calculation sheet) Click Here. A venturi tube can also be used to mix a liquid with a gas and siphon into the venturi flow. The siphonic mechanism keeps air out to produce a closed water column during drainage. 1 Introducti on 50 4. ﾂ Di7/iameter o% siphon i FmG. Worksheet inverted siphon xls Seepage design and curve of earthen dam. We re-examine the siphon process and recognize that the existing classic formula of the flow velocity of a Description. but situation is a conduit is taken out from dam. The discharge of submerged W eir is . Special care must be taken in inverted siphon design since losses are greater for pressurized flow, and the velocity in each siphon pipe must be at least 3 ft/s (0. Assign optimization and design of siphon well in a power plant circulating water[J]. Special care must be taken to upside-down siphons design since losses be greater for pressurized gush, and the velocity in each siphon pipe must can at fewest 3 ft/s (0. May 18, 2020 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Jan 8, 2021 · Abstract. 7 to 1. Case A (see Figure 6 and 7) A horizontal tube is filled with water between 2 reservoirs (see Figure 7). This report describes the design and operation of the siphon breaker experimental equipment from 1989 to FLOW-3D Modeling of a Siphon Spillway. Thermosiphoning is used for circulation of liquids and volatile gases in heating and cooling applications such as heat pumps, water heaters, boilers and furnaces. It will be a major effort to clear the plugged siphon. 0 Inches per Hour. filtration site using a novel hydraulic calculation tool “SIPHON”, which can be used for the design and rehabilitation of siphon well systems and (2) investigates the energy savings of siphon wells per cubic meter of abstracted water based on real data from two riverbank filtration (RBF) sites operating both siphon wells and individually Hydraulic & Pneumatic Design Engineering Fluid Flow Design and Engineering. Typical section for inverted Special care must be taken in inverted siphon design since losses are greater for pressurized flow, and the velocity in each siphon pipe must be at least 3 ft/s (0. Mid-Barataria Sediment Diversion. These conduits may also be used to measure the rate of flow. 2/3. Our civil and environmental customers now use FLOW-3D HYDRO for these types of modeling and analysis. land and water quality division. Civil Engineering Application & Design Resources Fluids Flow Design and Engineering. 8 to 2. e. In this equation, k is either 0. Clean this trap regularly - twice annually depending on the sediment load You do not want this trap to fill with more than 50% silt/debris. Use this calculator to quickly calculate the actual flow rate through the Venturi tube flow meter with only a few inputs. • Significant cost savings can be achieved by using a well‑planned Zurn Siphonic Drainage design. Munaf Al-Ramahee. Related Articles: Flash Vapour Calculation | Flash Vapour Recovery Vessel Design Calculation. Library. To transfer fluid from one reservoir to another reservoir without any external force. 9 m/s) for sanitary with 4 ft/s (1. Compared to gravity systems, this ensures a much higher flow velocity through smaller pipe diameters for fast and efficient drainage. From the results of the experiment, it was found that there are several design factors that affect the siphon breaking phenomenon. Sag Pipe (depressed sewers, or Inverted siphons) A sewer that drops below the hydraulic gradient to pass under an obstruction, such as a railroad cut, subway, highway, conduit, tunnel, valley or river, is often called a sag pipe. This report describes the design and operation of the siphon breaker experimental equipment from We would like to show you a description here but the site won’t allow us. The Siphon Flow Rate Calculator emerges as a valuable tool, aiding engineers and enthusiasts alike in quantifying the rate at which fluids move through a siphon. Explore all metrics. 04 MB) Rock A stormwater design engineer should be consulted for the necessary calculations. Design a sag pipe system using the following given conditions: 1. This calculator provides a practical tool for engineers, farmers, and hobbyists to estimate the flow rate of siphon systems, aiding in the design and troubleshooting of efficient fluid transfer applications. In this design, the seal is inherently maintained by a liquid level in the tank, and therefore, no instrumentation is required to monitor and maintain the seal. 2k. 1 Introduction 13 3. To drain sewage waters. 1 Introduction 4 2. 1 Citation. Dec 17, 2009 · If the siphon gets blocked by trash, your flow rate will decrease or even stop completely. Data Source: Peak Runoff Rate: 0 Gallons per Minute (GPM) 0 Cubic Feet per Second (CFS) Peak Runoff Volume: 0 Gallons. 101866d . Siphon Problem: Let’s consider a siphon, which is used to drain water from a tank, T1. Dm7/iameter o% main pipe FmG. 2 m/s) for storm water (Metcalf and Eddy, 1981). Siphon spillways have been used to help pass excess inflows (i. Siphon Discharge Rate Equations and Calculator . Once the down leg is completely full, the system becomes a true siphon and ends with that sucking sound when the tank and bowl are empty. Feb 23, 2019 · 2. 9 m/s) on sewage or 4 ft/s (1. p. It is necessary that the final end of the tube be lower than the liquid surface in the reservoir. Operating temperature: Pump materials and expansion, mechanical seal 2 STRATEGY ONSITE SYSTEM FOR DESIGN 2. water surface) in the wet well would need to be at the invert of the siphon discharge. To perform or verify the design of siphon-breaker Air Release Valves are probably the best known air valve and are typically furnished in sizes 1⁄2 in. The operating conditions Mar 6, 2017 · A bell siphon has three basic parts: a reservoir, the bell, and a riser. 1/2. The graph was created in a manner as to allow use across a variety of siphon sizes, pond sizes, drawdown volumes, and drawdown times. 2 Residential Wastewater Characteristics 50 MicroDrip_Design_2017-12-21 (8. The complex engineering topography inevitably requires the use of siphon drains with a total length of more than 150 m and a horizontal section length of more than 80 m, which 2. The design of siphons has many similarities to the design of culverts; however, unlike the design of culverts: siphons are usually designed for full pipe flow; siphons are usually designed to minimize head loss; siphons take the water down, then back up; USBR siphon designs are generally for an assumed 50-year useful life; Pipe Velocity Limit O%ten' all siphon inverts are locate! at the same elevation "the elevation o% the lo#est siphon$ %or ease o% construction. 2 Design calculation . Outside the bell, it’s exposed to the atmosphere from open top of the reservoir, and inside the bell it’s exposed to atmospheric pressure through Abstract. In this equation, n is the coefficient or roughness, R is the hydraulic radius, and S is the pitch or slope of the pipe. Conservative assumptions, along with an explicit safety factor, have been employed to assure a conservative design with an adequate overall safety factor. The pressure in the supplier may help determine if a siphon effect could indeed occur. can generate low pressure by making a siphon. Unlike the main sewer pipe, the siphon pipes flow under pressure and must have flow velocities greater than 3 ft/s (0. 1. V. 1. Siphon Spillway, 1990. height in a body of liquid. but the level of invert of siphon is higher than the conduit outlet level. For large effective heads, this height may be greater than 5 m. The liquid to be vaporized enters the reboiler at 80°C, and the heating medium (steam) is at 150°C. Data: Formula: Applying Bernoulli's equation for the points 1 and 2, ( i. Northwest Hydraulic Consultants used FLOW-3D to evaluate the discharge capacity of an existing 3-ft high rectangular siphon spillway. A Venturi meter is used to measure the flow rate through a tube or volumetric flow rate, Q. Nov 15, 2022 · Application Of Siphon. 4 m. 5 MB) Partially_Full_Pipe_Flow_Calculations (960. so that it could pass A siphon (also spelled syphon) is a continuous tube that allows liquid to drain from a reservoir through an intermediate point that is higher than the reservoir, the up-slope flow being driven only by hydrostatic pressure without any need for pumping. Also, make sure you include any headloss in the trash rack as well as the appropriate inlet loss before you finalize your pipe sizes. Sep 26, 2017 · A siphon breaker is a type of safety device that can be utilized to control the loss of coolant water effectively. 5 m/s. Dec 19, 2014 · jack miller . box 129261, san diego, ca 92112-9261 Example of Siphon Calculation. In general, the design and construction of the public wastewater collection system shall be in Jan 1, 2009 · STAAD Pro2006 software program was considering to structural analysis and design of inverted siphon. Variables 蕫ヂc& to calculation Aﾂ j75lo# area in the main pipe %or computing height o% #all D Fm>G. Unlike the main sewer pipe, to siphon tube flow under pressure and must have flow accelerations greater than 3 ft/s (0. In addition, the experimental system was to be modeled with the RELAP code and the predicted and measured performances compared. Download doc PREMIUM - 307. 8 CFS. The material which follows lays greater stress on tests of a standard low head siphon spillway design than on the proposed design of a seemingly better structure. 6 m, 4. 0 Cubic Feet. The siphon will discharge to a pump station wet well and I have considered that the highest "pump on" level (i. department of environmental health . For the 12-Inch HDPE 3 to 5 CFS. 5 m above the water surface. I have searched some literatures and found that minimum velocity criteria is around 2. 486/n) R 2/3 S 1/2. 1 GRAVITY SEWER PIPELINE DESIGN 6. Learn about the bioengineering research at Clemson University, including theses, dissertations, and publications from faculty and students. BURLACHENKO. 9 m/s) for sewage or 4 ft/s (1. In wastewater systems, siphons are installed most often in concrete or fiberglass dosing septic tanks ranging in size from 500 to several thousand gallons. To establish a basis for the design and review of plans and specifications for public wastewater collection systems. Sep 26, 2022 · Slope siphon drainage is a convenient and efficient above-ground drainage method that is free of manual power and can effectively maintain the stability of potential landslides and prevent the loss of life and property. 4 References 48 4 WASTEWATER RICHARACTESTICS 4. that corresponds to the maximum allowable liquid level in the tank. itsmoked (Electrical) 18 Dec 09 15:59. The making of a siphon Let’s build a siphon from scratch to see how it really works. 3 Site Evaluation Strategy 17 3. 1 m/s The arrangement of inlet and outlet details must divert the normal flow to one barrel. Concrete siphon pipe with trash guard, valve box, and drain details. 25 Ramiro eber guerrero gonzales . 3 days ago · First use the Hazen-Williams equation to find the velocity of the fluid: v = k × C × R 0. 54. These spillways can be designed to be self-priming or manually primed. N. P 337. Compute the diameter of each siphon, Di, or the flow through each siphon, Qi, using Manning's May 9, 2016 · A better method is to use the pressure drop across the siphon pipe, estimated at 0. In an inverted siphon the hydraulic gradient line is above the flow-line, whereas in true siphon the hydraulic line is below the flow line. The rate of flow from is used only for siphons and pipes where the flow exits the tube into free air. The valve has a small precision orifice in the range of 1/16 in. o. Equation 1: Manning’s Formula for Gravity Flow. h is the height difference between the source and destination of the liquid. 5600. Thus, several siphons owning lighter diameters than the main sewer may be required. 3 m. , augment other hydraulic structure discharge capacity). water is to be delivers to inverted siphon immediately after impact wall. The following important points should be considered in the design phase of pumping systems: Acidity/alkalinity (pH) and chemical composition: Corrosive and acidic fluids can degrade pumps and should be considered when selecting pump materials. This study focused on the aeration the flow through the aerator holes placed on the hood to prevent cavitational damage in high-head siphon-shaft spillways. 03 KB) Riser_Barrel_Hydraulics_with_Schematic (203. For the 6-Inch HDPE, 0. 3. 11 KB) Pipe_Weight_Calculator_Spreadsheet (104. (1. Dia. now my question is whether siphon will pass water with out any disturbance or to lower the invert level of siphon and create a head on it. Venturi Flow Equation and Calculator. “These types of control structures are suited for service, auxiliary and emergency spillways, and/or outlet works. As part of the guidelines developed Siphon Spillways. A siphon break is provided at the top of the seal to avoid siphoning the whole tank content to the drain. 60m Length of Siphon = 400 m (57 m (in down slope) + 71m (horizontal) +132ft (sloping down)+100 m horizontal+40m (steep slope up)) see in the figure DESIGN PIPELIFE siphonic roof drainage systems utilize negative pressure to evacuate rainwater with high flow rates. 7 psi with plastic pipe when flowing at 3-5 cfs. assisant director . (c) siphon. d is the vertical depth of the dip in the siphon. • A poor design can lead to blockages, sediment build up and direct impacts on minimum velocities that are critical in siphons. These modifications are:1) modification on the assumed initial base points, 2) modification on the value of step length, 3 Sep 23, 2021 · Siphon-shaft spillways are constituted by covering above a shaft spillway with a hood that creates siphonic pressure. All charts have a range of operating heads specified in 20 mm increments up to a maximum of 1 m. S. This calculator performs the flow rate calculation from the measured pressure difference caused by the flow contraction in the throat of the Venturi tube. For the calculation and design of siphons a free easy to use excel sheet to be shared and used in hydraulics, greetings. Our inverted siphon calculation allows up to five parallel siphons to go under the river. Unlike the main sewer tubing, the siphon pipe(s) flow on pressure. Inverted siphon structure is a common water conveyance buildings, this paper adopts finite element calculation software to carry out three-dimensional finite element simulation analysis for Zhangcun tunnel type inverted siphon structure, computer is used fully as efficient computational tools. 9 m/s) to keep material suspended. Correlation for experiments reported in [2] The undershoot reported in the experiments of [2] are for a pipe diameter of 16” (≈ 400 mm), a flowrate giving a water veloci ty of 3. These flow give the same pressure drop across the 205 feet of pipe. of gravity sewer to be connected by sag pipe = 910 mm (36 in) calculation. it can be greater than atmospheric pressure expressed in feet of the fluid being used minus the friction loss). 8k. Sewer Design Escort. g is the acceleration due to gravity (approximately 9. 93 KB. The velocity in siphon should not be generally less Nov 6, 2016 · Download PDF. 1 PURPOSE The purpose of this section is to provide guidelines for the use, location, alignment and design of gravity sewer collection pipelines for conveying raw sewage. 0 m and 4. • Provides an innovative design solution that reduces the amount of drainage pipe, reduces the diameter of the drainage pipe, and provides more free space per square footage in the building. Using a 2 year, 24 hour peak runoff rate from the 47. V = (1. For the 8-Inch HDPE, 1. 4-2. The formula to calculate the flow rate in a siphon system is: Q=2⋅g⋅h⋅(h+d) Where: Q is the flow rate. Apr 18, 2017 · Online Calculation Sheet for Robert Evaporator Body Design ( Note :In this calculator provided with two types of sheets. Q = 1. 15 CFS. Specially take needs be taken in inverse siphon design after losses are greater for pressurized flow, and the velocity in each siphon pipe must be at least 3 ft/s (0. Assorted. By utilizing this calculator, users can optimize fluid transfer processes, design efficient siphon systems, and ensure the smooth operation of diverse applications. Tags: M and S Standard Plans. 81 m/s² on Earth). Deducing variation law of the inverted siphon's stress and displacement in construction process and of operating head (in mm) and siphon internal diameter (ID, in mm). This paper puts forward anew theory on the operation of syphons. Dissimilar which main cloaca pipe, the siphon pipe(s) flow under force. 347. We are designing an inverted siphon with the following data Dicharge = 54 cusecs Manning's = 0. The following table represent an uncertainty for discharge of about +/-15 percent. 4 m above the water surface in the tank, estimate the pressure of fluid at the point of siphon. Calculate the discharge and pressure of the fluid at the discharge point. 849 for metric or 1. When opening height is raised above 0. Jan 30, 2023 · A. (13 mm) through 3 in. The aforementioned Conventionally designed systems use simple “pipe schedule” tables derived from Manning’s Formula (Shown as Equation 1). elizabeth pozzebon . For any given . May 1, 2024 · If the peak point of the siphon is 1. 5 ha m (16 ac ft) of storage. Jun 10, 2021 · An inverted syphon is a hydraulic structure utilized to convey open channel flow under obstructions. A system must allow any barrel to be taken out of service for cleaning. Jul 16, 2002 · 1) Use a inlet structure with a minimum 24" deep sump (but no less than the 75% of the pipe diameter) as a sediment trap. b. widened to accommodate the conveyance of siphon flow to the Wilkinson Pump Station, but that no new right of way will be required. The lengths specified are 3. Siphons have been known and used since ancient times and are still widely used. Bukhartsev. Siphons having a throat height of up to 3 m are simpler to construct and easier to prime and operate. Installation of an air vacuum valve of the appropriate size at the appropriate location could break the water seal and prevent a siphon effect. Since the existing siphon experienced issues with self-priming during That calculation runs siphon diameters (or trap flows), velocities, inlet chamber wall heights, and siphon drehen elevations. The regional transmission system owned and maintained by OCSD includes 475 miles of interceptor and trunk sewer lines. 011 (MS pipe will be used throughout the siphon) U/s water level= 466. 243 Accesses. To establish the minimum design criteria for public wastewater collection systems to minimize long-term maintenance needs. Provisions must be made to allow The Siphon Breaker Design Requirements Project was intended to • provide experimental data on siphon flow effects. (2) Changes of direction in inverted siphons should be easy and gradual. Many examples solved to check the accuracy of the written program. 78Z eff. 63 KB) Riprap_Lined_Waterway_Design_Calculator (1. Rainwater Harvesting a siphon corresponds to a throat cross-section height of 0. Use the peak daily flow for calculations with pipe flowing full. The local collection sewers are owned and maintained by the member agencies. May 4, 2007 · I'd feel much more comfortable if there was a bit more cushion in the design so I have a question regarding free flow discharge from the siphon. This pipe is drop sharply, then run horizontal under the obstruction, and finally rises to the desired elevation. 2. It proposes, and gives proof from test results, that the rising leg of a syphon can be greater than heretofore thought (i. Calculations. Inverted siphons are also known as depressed sewers, because the sewer portion at such portion is below the general sewer line. The Siphon Float System may be used in both dry and wet sediment basins. Mar 1, 1993 · The Siphon Breaker Design Requirements Project was intended to provide experimental data on siphon flow effects. 3 to 0. lq nh nw en vu cn dj hh jb tf