Air separation and dirt removal equipment

Transcription

1 ir separation and dirt removal equipment Literature ref: 4/2 RGISTRD UKS QULITY MNGMNT S N ISO 91 Certificate No: FM 49 Flamco UK Limited Unit 4, St. Michael s Road, Lea Green Industrial state, St. Helens, Merseyside W9 4WZ. Telephone: Fax:

2 ir separation and dirt removal equipment ir in heating and air conditioning systems Henry's law in a cooling system mount of air liberated from the water 5 P Temperature pressure. When the temperature of water at constant pressure is raised, for example from to 2 O C, Henry's law can be used to determine the amount of dissolved air which is liberated from the water. mount of air liberated from the water 75 4 P Temperature 2.2 pressure 2 Lowering the pressure of the water at constant temperature also results in dissolved air being liberated. Henry's law in a central heating system. mount of air liberated from the water When the temperature of water at constant pressure is raised, for example from 2 to O C Henry's law can be used to determine the amount of dissolved air which is liberated from the water. mount of air liberated from the water Temperature pressure Temperature pressure Lowering the pressure of the water at constant temperature also results in dissolved air being liberated. 2 The presence of air in heating and air conditioning systems causes the following problems: l Irritating noise. l Reduced heat transfer. l Corrosion. l Damage to circulating pumps. l Loss of efficiency. l Increased energy consumption. l High maintenance costs. Causes of air occuring in heating / air conditioning systems To overcome the above problems, it is necessary to analyse the causes of air being present in a system: l ir is present before filling the system. l ir is trapped in the system when filled. l ir is entrained in mains water when filling. l ir is dissolved in water when filled. The presence of air dissolved in water can be explained by reference to Henry's Law. This states that C = K x P where C = concentration of dissolved air. K = absorption factor (dependent on temperature). P = pressure. From the diagram (right) it is apparent that the amount of air which is dissolved in water, is dependent on temperature and pressure. ir dissolved in water is liberated when the temperature rises or the pressure falls. Henry's law in a cooling system C normal dm air per kg water T Temperature in C C pressure in bar absolute In cooling systems part of the air is dissolved in water and part is air bubbles. When the water (and air) runs through the system it encounters different temperatures and pressures. Henry's Law says that during these temperature /pressure fluctuations air is successively liberated from and dissolved in the water. Pressure has the largest influence on the formation of air bubbles in a cooling system. The largest air bubbles will appear in places with low pressure (the upper part of the system), this is therefore the best place to site a Flamcovent. The temperature of water in the coil decreases which means that part of the air bubbles will again dissolve in the water, it is therefore preferable to mount a Flamcovent before the coil. To prevent air bubbles causing pump damage due to cavitation, a Flamcovent should be installed before the pump. Henry's law in a central heating system Very high temperatures occur at the combustion chamber wall of the boiler. It is here that very small air bubbles will be liberated from water containing air. These so called 'microbubbles' will be redissolved elsewhere in the system where the temperature is lower, unless they are immediately removed. If the microbubbles are removed immediately upon leaving the boiler, the air free (unsaturated) water results. ir present elsewhere in the system can be dissolved (absorbed) in this water. This absorption effect is utilised to bind all the free air in the system and to vent it to the outside by the combination of the boiler and the Flamcovent. This venting process is continuous until eventually the water that remains is strongly unsaturated. C

3 Flexvent and Flexvent Super automatic air vents The Flexvent automatic air vent can be used in both open and sealed cooling and heating systems. Flexvent, excluding type 1/8 and type H, are supplied with a shut off valve. When the Flexvent is disconnected from the shut off valve, the valve will close automatically making it easy to exchange or clean without draining down. To operate, the red cap should be turned one revolution anticlockwise. Flexvent type H has a 9 O angled connection for mounting on a radiator. Flexvent type P incorporates an air intake preventer. Principle of operation The Flexvent float keeps the venting valve closed. When air is collected inside the float chamber, the water level inside the Flexvent will decrease and the venting valve will open. The collected air will escape through the venting valve and the water level inside the Flexvent will increase again, which in turn closes off the venting valve. This process is continuous as long as air is collected in the Flexvent. The air cushion in the upper part of the Flexvent protects the venting valve against pollution. When the pressure inside the system is decreased below the ambient pressure, for instance during draining, the Flexvent acts as a vent. Open Closed Flexvent installation Flexvents should be mounted in a vertical position where air is collected naturally in the system Flexvent The Flexvent Super is made of. The venting valve is incorporated in the air chamber so that damage from the outside is almost impossible. The air chamber is conical in shape. The advantage of this construction is venting valve venting valve that the clearance between the water level and venting valve is larger than in a straight chamber. For example if both straight and conical shaped chambers have the same height and bottom surface area, when the water level rises the pressure rise in the conical shape will be faster than the straight shape due to the smaller volume. Therefore the pressure balance in the conical shape will be reached at a lower water level. Dirt floating on the water in the Flexvent Super will remain clear of the venting valve in normal conditions. This means that fouling of the gearing and venting valve is reduced to a minimum. ø2 ø2 ø2 ø2 ø2 ø2 water level a water level Water level after filling the system a l/min bar flexvent max. bar max 12 C 1/8" SP Flexvent 1/8 65 flexvent 82 max. bar max 12 C /8" SP Flexvent /8 77 flexvent 88 max. bar max 12 C 1/8" SP Flexvent 1/8/8 /8" SP flexvent 82 max. bar max 12 C 1/2" SP Flexvent 1/2 flexvent max. bar max 12 C 9 /8" SP Flexvent P /8 flexvent max. bar max 12 C 9 1/2" SP Flexvent P 1/ flexvent H 6 51 Flexvent H 1/2 1/2" SP 119 flexvent super 1/2" SP 7 Flexvent Super l/min Flexvent Super bar Type Connection Max. Max. pressure Material temp. bar Flexvent 1/8 Flexvent /8 Flexvent 1/8/8 Flexvent 1/2 Flexvent P /8 Flexvent P 1/2 Flexvent H Flexvent Super Flexvent Super K22 1/8"(M) /8"(M) 1/8" and /8"(M) 1/2"(M) /8"(M) 1/2"(M) 1/2"(M) 1/2"(F) 1/2"(F) 12 O C 12 O C 12 O C 12 O C 12 O C 12 O C 12 O C 12 O C 12 O C nickel plated Shutoff valve no yes yes yes yes yes no optional optional

4 max. bar max 12 C Flexair air separators Flexair air separators can be used in sealed heating and cooling systems up to a maximum temperature of 12 O C and a maximum pressure of bar. The Flexair air separator is available in three different types: with threaded connections, with welded connections and with flanged connections. The connection dimensions conform to ISO standards. Principle of operation Operation of the Flexair air separator is based on the principle of centrifuge. Due to the tangential mounted connections, the water inside the Flexair is forced to rotate. This rotation forces the heavy medium the water against the wall of the Flexair while the air is collected in the middle of the Flexair. flexvent side view top view Mounted on top of the Flexair unit is a Flexvent air vent which will automatically discharge any air collected in the unit. Flexairs up to type 5 have a standard Flexvent and larger units are fitted with a Flexvent Super. Impurities which are heavier than water such as sand, weld debris etc., will collect in the bowl shaped lower section of the air separator. These impurities can be readily removed through the drain plug located at the base of the unit. Flexair air separators resistance diagram bar.5 kpa /4" 22ø 1"ø 1 1/4"ø 5ø 1 1/2"ø 65ø ø ø 125ø 15ø 2ø Pressure loss Flexair installation We recommend that the Flexair be connected to the suction side of the circulating pump on the flow Flow m /h

5 Flexair air separators ØD Flexair 1" 2" G Flexair 25 5 S Type Dimensions in mm Contents litres ØD F G Weight kg Flexair 1 G Flexair 1 1/4 G Flexair 1 1/2 G Flexair 2 G " 1 1/4" 1 1/2" 2" Flexair 25 S Flexair 2 S Flexair 4 S Flexair 5 S F F ød Flexair S ØD Flexair F G Type Dimensions in mm Contents litres ØD F G Weight kg Flexair 65S Flexair S Flexair S Flexair 125S Flexair 15S Sizes 2F to 6F are available to special order. Flexair 65F Flexair F Flexair F Flexair 125F Flexair 15F

6 Flamcovent microbubble air separators Flamcovent air separators are used for the virtual elimination of air from central heating and cooling systems up to a maximum temperature of 12 O C and a maximum pressure of bar. The principle on which Flamcovent air separators are based is a completely new method of removing gases from water the PLL ring process. (Patented). y applying this process, it is possible to remove: l l l air which is present in the system water in the form of small bubbles and microbubbles; air which is dissolved in the system water; air which is present where a Flamco automatic air vent cannot be installed. The Flamcovent air separator is available in two body types: Flamcovent with female thread or compression fittings and housing; Flamcovent with welded or flanged connection and steel housing. Operating principle of Flamcovent microbubble air separators Flamcovent air separators utilise the highly efficient and effective PLL ring method of removing gases from liquids. The PLL ring has been developed from the Raschig ring and has been used for many years in the processing industry. The use of PLL rings to remove air from central heating and cooling systems is however new. (Patented). The operating principle of the PLL rings results from the special properties which they possess, namely: l l l large surface area per m ; high probability of collision and adhesion; low resistance to fluid flow. Flamcovent and the coalescence effect The operation of Flamcovent air separators is based on the concept of coalescence. This means in practice that small air bubbles tend to adhere to a surface, and then grow together to form larger bubbles. When a stream of fluid flows past and through PLL rings, the stream is deflected in many different directions. The construction of the PLL ring is such that all the fluid is brought into contact with the total surface of the PLL ring that is available for adhesion. The microscopically small air bubbles present in the fluid attach themselves to the contact surface of the PLL ring. Once these microbubbles have grown to form larger bubbles, they can be separated from the fluid. The adhesion of of air bubbles after which they grow and become separable is known as 'coalescence'. large number of PLL rings are applied in the Flamcovent air separators, (from 115 in the smallest to 4 in the largest), so that a very large contact and adhesion surface is obtained.

7 Flamcovent microbubble air separators Construction of Flamcovent. 1. ir chamber. 2. rass housing.. Venting valve. 4. Float. 5. Gearing. 6. PLL rings. 7. Protective filter 5 6 Construction of steel Flamcovent. 1. ir chamber. 2. Venting valve.. Housing. 4. Flushing cock 5. Float. 6. PLL rings. 7. Drain valve COOLING SYSTM HTING SYSTM Operation The velocity with which water flows into the Flamcovent will be greatly reduced as a result of the enlargement of the flow passage. The larger air bubbles are thus given time and opportunity to rise upwards to the air chamber. t the same time, the stream of water collides with the many PLL rings present. s a result, very many small, evenly distributed currents are created in and around each PLL ring, so that all gas containing water particles are brought into contact with the entire PLL ring contact surface. ven the smallest microbubbles present in the water will adhere to the surface of the PLL ring. Since the stream of water in the Flamcovent comes to a complete standstill, the microbubbles can accumulate in the direction of the overlying chamber. The float mechanism and venting valve serve to expel the air separated from the water to the outside, and keep the volume of the air chamber constant. Construction Flamcovents are constructed from a vertical housing on which an air chamber is mounted. The housing contains the PLL rings which ensure a very large contact area with minimal resistance. The float, float mechanism and venting valve are located in the air chamber. The air chamber is conical in shape. Compared with a straight chamber this design ensures maximum clearance between the water and venting valve to prevent fouling of the mechanism. (See diagram ). dditional protection is given by the filter between the water and the air chamber. The larger steel Flamcovents (types 5 to 4) incorporate a flushing cock to eliminate floating impurities and may be used to release large quantities of air, for instance during filling. Impurities heavier than water will collect in Diagram. venting valve venting valve the lower bowl shaped part of the unit and these may be removed by means of the drain valve at the base. The venting valve is secured in the air chamber so that external damage is not possible. There is a facility to close the venting valve with the screw located in the outlet. Installation water level a Water level after filling the system Cooling systems ir bubbles that exist in the system will have a larger size before the coil than after. This is due to lower water temperature after the coil (Henry's law). Therefore in order to discharge the air as efficiently as possible, the Flamcovent should be installed in the flow circuit just before the coil. It should also be installed before the pump to prevent air bubbles from damaging the pump. It is recommended that a Flamcovent be installed on each floor above m. Heating systems Microbubbles which are liberated from the water in the boiler (high temperature) will be redissolved elsewhere in the system (lower temperature) if they are not immediately removed. Therefore in order to discharge air as efficiently as possible, the Flamcovent should be installed in the flow circuit immediately after the boiler or mixing valve. Install before the pump to prevent air bubbles damaging the pump and to prevent air bubbles being reduced to smaller bubbles by the pump's action. It is recommended that a Flamcovent be installed on each floor above m. water level When installed in existing boiler house with supply circuit directly beneath the ceiling, mount Flamcovent as above. For service purposes clearance '' should be at least mm. a

8 Flamcovent microbubble air separators Selection procedure (Heating and cooling systems) Flamcovent effectiveness depends on the system water speed. For best effect we advise a water speed of not higher than 1 1/2 m/s when installed in the optimum position (highest temperature, lowest pressure), and 1 m/s when it is not. If the Flamcovent is installed in a system with higher water speeds then adaptors must be fitted on inlet and outlet to decrease the water speed. The adaptors must divert no more than 4 O. with 1 1/2 m/s resp. 1 m/s in the entrance of the Flamcovent. xample: Flow capacity=7m/h. (refer to graphs below) ). Installed in the attic, max. allowable water speed 1 1/2 ms; select point (7m/h flow) and travel up to 1 1/2 ms curve (point ) and read to left for correct Flamcovent, in this case 125*. ). Installed in the basement, max. allowable water speed 1 ms; select point (7m/h flow) and travel up to 1 ms curve (point C) and read to left for correct Flamcovent, in this case 15* *lways choose the dimension nearest above the end point on the axis. Flamovent () 1 1/2" 1 1/4" 1" Ø22 /4" v= 1 m/s v=1 1/2 m/s Flamcovent Resistance Diagram Flow l/s Pressure loss kpa ø 22/4" 1" 1 1/4" 1 1/2"ø5 ø65 ø ø ø125 ø15 ø2 ø25 ø ø5 ø4 Flamovent (steel) Flow m /h v= 1 m/s v=1 1/2 m/s C Flow m /h

9 Flamcovent microbubble air separators Types and specification Type Dimensions in mm ØD S.O.J F G Contents litres Weight Kg Flamcovent Flamcovent 22 Flamcovent /4 Flamcovent 1 Flamcovent 1 1/4 Flamcovent 1 1/ /4" 1" 1 1/4" 1 1/2" Flamcovent welded connection Flamcovent 5S Flamcovent 65S Flamcovent S Flamcovent S Flamcovent 125S Flamcovent 15S Flamcovent 2S Flamcovent 25S Flamcovent S Flamcovent 5S Flamcovent 4S Sizes 5F and 6F are available to special order. Flamcovent flanged connection DIN 26 (ND 16) Flamcovent 5F Flamcovent 65F Flamcovent F Flamcovent F Flamcovent 125F Flamcovent 15F Flamcovent 2F Flamcovent 25F Flamcovent F Flamcovent 5F Flamcovent 4F ØD F rass Flamcovent (22 and /4 to 1.1/2) G Steel Flamcovent (Type S and F)

10 Flexcon S dirt interceptors unique range of high efficiency dirt interceptors for the removal of impurities from commercial heating and air conditioning systems. Specification Construction: Maximum working pressure: Maximum operating temperature: Insulation: Steel welded fabrication. 5 bar. bar available 12 O C. Optional extra. 2 7 Principle of operation 1 1. Reservoir. 2. Inlet.. Outlet. 4. Sludge pipe. 5. Isolating valve. 6. Perforation plate. 7. utomatic air vent Type Capacity Litres Dimensions in mm ød with ød insulation H Flow rate m /h Weight dry kg Flexcon S Flexcon S 1 Flexcon S 1 Flexcon S Flexcon S 4 Flexcon S 6 Flexcon S Flexcon S DN ød DN H 15 ød Flexcon S DN 25 Flexcon S with insulation.

11 Flamcovent Clean microbubble air separator with dirt chamber The Flamcovent Clean has been specially designed to separate solid particles as well as air from a heating and cooling installation. Practical experience and testing have shown that the PLL rings inside the Flamcovent will separate solid particles as well as air bubbles from the mainstream of the installation. The construction of the Flamcovent has been changed in such a way that in the enlarged bottom bowl a nonturbulent area is created. This allows relatively heavy particles to sink to the bottom of the Flamcovent Clean where there are no vortices to force the particles back into the system again. The collected particles can be drained from the system through the ball valve at the base of the unit. There are no PLL rings or obstacles in the bottom bowl to prevent the collected particles from being drained away. Lightweight solid particles that float in the water within the Flamcovent Clean can be drained out through the drain valve on the side of the body. The capacity of the Flamcovent Clean to separate solid particles from the system has been tested and reported on by the Dutch TNO Institute of nvironmental and nergy Technology (Report number R9564). The summary of the results and the conclusions of this report are shown below. The operating principle for air separation of the Flamcovent Clean is equal to the standard Flamcovent. For operating principle, selection criteria and technical data please refer to the Flamcovent air separator. TNO report TNO report Removal of suspended solids by the Flamcovent Clean Conclusion Removal of suspended solids by the Flamcovent Clean Table 5 Summary of results The Flamcovent Clean has a better performance in separating suspended particles than the conventional Flamcovent (compare TNOreport 9284). This holds for both fine and coarse particles. The removal efficiency of suspended particles increases with: decreasing flow velocity; increasing circulation fold; increasing settling velocity of particles, hence with larger and more dense particles. Flamcovent Clean proves to be well capable of removing suspended particles from a water circuit. Sand particles larger than 8 µm (or particles with a similar sedimentation behaviour) are removed well over 99% at a circulation fold of 5, using a flow rate of.5 m/s. lthough lower removal efficiencies are obtained at a flow rate of 1. m/s, still over 9% of the fine particles (8 6µm) and over 99% of the coarse fraction (212 25µm) is removed at a circulation fold of 5. xperiment number Flow rate (m/s) Circulation fold Overall (825µm) Removal efficiency (%) Fine fraction (86µm) Coarse (21225µm) Overall removal efficiency (%) Flow =.5 m/s Flow = 1. m/s Figure 5 The overall removal efficiency (825 µm particles) of the Flamcovent Clean for two different flow rates

12 Flamcovent Clean microbubble air separator with dirt chamber Flamcovent Clean. Types and specification Type Connection xternal pipe diameter (mm) Flamcovent Clean Flamcovent Clean 5S Flamcovent Clean 65S Flamcovent Clean S Flamcovent Clean S Flamcovent Clean 125S Flamcovent Clean 15S welded connections DN 5 DN 65 DN DN DN 125 DN Flamcovent Clean Flamcovent Clean 5F Flamcovent Clean 65F Flamcovent Clean F Flamcovent Clean F Flamcovent Clean 125F Flamcovent Clean 15F flanged connections DIN 26 (ND 16) DN 5 DN 65 DN DN DN 125 DN Dimensions llow at least mm for access Type Dimensions in mm ØD Content in litres Weight kg Flamcovent Clean welded connections /4" male ØD llow at least mm for access ØD Flamcovent Clean 5S Flamcovent Clean 65S Flamcovent Clean S Flamcovent Clean S Flamcovent Clean 125S Flamcovent Clean 15S Flamcovent Clean flanged connections DIN 26 (ND 16) Flamcovent Clean 5F Flamcovent Clean 65F Flamcovent Clean F Flamcovent Clean F Flamcovent Clean 125F Flamcovent Clean 15F Sizes 2 to are available to special order. /4" male Flamco UK Ltd reserve the right to alter specification and design without prior notice. Dimensions are in millimetres and are approximate.