Air Cooled Compressors

Air Cooled Compressors are used more and more often in today's industries and come in three main types:

• Rotary Screw
• Rotary Centrifugal
• Reciprocating

I will explain how the three types work and how they vary from each other:

Rotary Screw Compressors

This type is known as a positive displacement compressor, they consist of two rotors, the rotors are enclosed in casing and internally compress the air. These systems are all oil cooled and contain no valves (the oil coolers themselves are water or air cooled).

The internal mechanism never experiences extreme temperatures whilst operating; this is due to all the cooling taking place inside the unit.

They are very easy to operate and maintain with a few advantages:

• Compact in Size
• Pulse-free Air
• Smooth Air
• High Output Volume
• Long Life

Rotary Centrifugal

These are known as dynamic compressors and rely on the transfer on energy from a rotating impeller to the air. They produce a very high pressure discharge, in order to achieve this they rotate at speeds far superior to the other two types, the flow through is continuous and therefore are designed for a higher capacity. They have guide vanes at the front of the system, these slides open and closed and are designed to reduce and increase the capacity. Rotary Centrifugal Compressors are oil free by design.

Reciprocating

Known as positive displacement machines, they are available air or water cooled and also lubricated or non-lubricated in configuration. They offer a very wide range of pressure and capacities, all varying in price and power.

Please visit here Oil cooler.

Improve Effectiveness of Evaporative Coolers

Ordinary coolers may not be effective in places where temperatures can reach over 100 degrees in summers. Most people use roof mounted coolers that are ineffective as they are placed directly under the sun. To cool your home in summers, it is a good idea to use evaporative coolers especially if you live in area where the temperature is hot and dry. 

However, before you install an evaporative cooler, it is important that you decide on the place where you are going to install the cooler. Installing the cooler in the right place will ensure your home is cool and you save on your electric bills.

Before you buy an evaporative cooler, you need to find if the coolers will be effective in the area you live. The effectiveness of evaporative coolers depends on the uninterrupted transfer of moist air. If you live in an area that has dry environment, they will work well. However, if you live next to the sea or in an area that has humid environment, they become less effective.

If you have decided to buy an evaporative cooler, you need to decide on the placement of the cooler. There are different designs of evaporative coolers that are available in the market. 

The ideal placement of the cooler will be in an area that is shaded in the hottest period of the day. Avoid keeping it close to plants that may shed leaves which can block the filter. Make sure the cooler can be easily accessed because you may have to carry out maintenance at least once a month. Install the cooler away from dumpsters as it vent odor and bacteria into your home. If you are planning to buy a new cooler, make sure you get the right size for your home. If you buy a cooler that is too large, you may find it difficult to install it. If you buy a cooler that is too small as it may be ineffective in cooling your home.

You must carry out routine maintenance of the oil cooler if you want them to cool your home without any hitch. Some of the activities that you must undertake to ensure the smooth functioning of the cooler include cleaning the filter, checking for leaks in the water line and oiling the bearing. If you plan to fill the oil reservoir, make sure you get special oil that is sold in hardware stores. People who live in a hard water area can add a filter to the water line. When doing the maintenance of the machine, make sure you check if all the water distribution lines that are connected to the spider are dripping.

Engine Oil Coolers

All engines require a cooling system which is provided by the radiator system containing water. However, high-performance autos used in competitive motor sports, or vehicles whose engines have to work hard to carry large weights or two other vehicles have benefited from the installation of separate engine oil cooler. In order to remove one third of the heat generated by the engine, the integration of reliable and efficient engine oil coolers is becoming more common in all types of motor vehicles.

Generally, a car's engine has two cooling systems which can be found on the top of the engine and its surrounding area. Ideally, the operating range of engine oil must be kept within 180 to 200 Fahrenheit. It is important that the oil maintain this temperature range to ensure that it will perform its intended functions correctly.

As the modern auto engines in newly manufactured cars tend to be smaller and faster running than previous designs, they produce more heat. Because of this the maintenance of oil temperatures within acceptable levels is critical. Smaller engines also have reduced oil capacity. This means that there is extra stress put on all the engine components and the motor oil is even more important in ensuring the smooth running of every part.

How Oil Coolers Work

Oil coolers come with two basic designs -- the tube-and-fin style coolers and the stacked plate coolers. With tube-and-fin style coolers, heat produced by the engine is extracted through the tubes and carried to the fins, where it will be sopped up with the air flowing from the cooler. Different types of tubes are used by varying cooler manufacturers. Some make use of swizzle stick like agitators which are embedded inside the tubes in order to preclude oil sludge build-up. However, the result from this can be quite random and often results in minimal improvement to the cooler's overall efficiency.

The stacked plate coolers, on the other hand, disperse heat by allowing the oil to flow into multiple passages inside the stacked plates. Stacked style coolers are designed to cool the oil by air flow passing over the multiple plates, however the elements are stacked so close together that it inhibits air flow in the cooler, and they are not as efficient as they should be. The stacked plate oil cooler design is not applicable for automobiles that are subjected to stressful environments like those competing in auto racing.

Efficient Oil Coolers

In particular, the Perma-Cool engine cooler with its patented "Turbulator" is gaining reputation as being more efficient than both the tube and fin or stacked style coolers. It offers numerous benefits and available in varying cooling kits.

The advantages that you'll enjoy with this kind of engine cooler include the following:

• Maximum cooling efficiency without compromising oil flow
• Reduction of oil temperature to acceptable levels
• Significant heat subjugation on the engine and radiator
• Improved capacity of oil system
• Hopefully, this information will help you gain enough knowledge about the use and importance of engine oil coolers.

New AD60 Adds Capacity, Enhanced Cooling Efficiency and Increased Operator Comfort to the Cat® Underground Articulated Truck Range

The new AD60, with a rated payload capacity of 66 tons (60 tonnes), is now the largest model in the Cat® range of underground articulated trucks, providing a 9 percent capacity increase over the proven AD55B. The new truck incorporates advanced heat-shielding and cooling technology, significant refinement of its Cat C27 ACERT™ engine, enhanced ride characteristics, and now-standard monitoring systems, including the Cat VIMS™ Guardian and Truck Payload Management systems. Premium standard features include a choice of integrated body styles, electronic retarding, climate-controlled cab and ground level servicing.

Engine and cooling

The Cat C27 engine, rated at 776 to 805 gross horsepower (579 to 600 kW), has been significantly refined for the AD60, including new pistons and high temperature fuel injectors, more durable rocker arm assemblies, a redesigned crankshaft lubrication system, a high efficiency engine oil cooler and a higher capacity fuel cooler. The sum of these refinements is added durability, reliability and cooling efficiency for the C27.

New for the AD60 is a remote-mounted transmission oil cooler that ensures optimum operating temperature for the seven-speed Cat planetary powershift transmission, which features a lock-up torque converter for efficient, fuel-saving operation, as well as an electronically controlled retarding system for optimum safety and productivity. The new cooler lessens the heat load on the engine oil cooler, allowing the engine cooler to function more efficiently.

The new heat-shielding system isolates heat from the exhaust manifolds, turbocharger impeller, and exhaust piping to reduce engine compartment temperatures and to provide a cooler environment for surrounding components. In addition to being more effective, the heat shield is also easier to install and remove. New ventilated hoods and covers allow effective heat dissipation and assist in passive cooling of component compartments.

Operator environment and suspension

The spacious, comfortable, well protected operator station is now equipped with a standard air-ride seat, the Cat Comfort TLV2, which features electric adjustment of firmness and a design that minimizes vertical and lateral motion imparted to the operator. Updates to the front suspension system contribute to ride stability and operator comfort.

Value-adding features

Premium features in the AD60 design include electronic integration of the engine and drive train, providing controlled-throttle shifting, overspeed protection, and body-up shift inhibitor. The now standard Truck Payload Management System calculates payload data, and the VIMS Guardian System provides operators, service technicians and managers with machine health information to ensure high mechanical availability.

The choice of a dump or ejector body allows tailoring the AD60 to different applications, and the single-stage hoist cylinder speeds cycle times. The frame design features box-section construction with materials and welding techniques that optimize structural life, and the articulation/oscillation hitch promotes stability and maneuverability in all types of ground conditions.

Four-wheel, oil-cooled, multiple disc brakes provide reliable, non-fade stopping power, adding to the AD60 safety features, which include an integral ROPS/FOPS cab, ground-level shut-down switch, operator presence system, anti-skid deck surfaces, and push-out safety glass.



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Oil Cooler and A/C Condenser Fan Testing

A very common failure on the 993 is the failure of the systems controlling the fans in either front wing for the oil cooler (RH side) and air conditioning condenser (LH side). There are a variety of components in the systems such as control units, temp sensors, relays etc, which can make the system fail totally, but the most common failure is in the circuits controlling slow speed fan operation.

With the oil cooling system, there is first a thermostat controlling flow to the cooler once the oil warms up (>83C). Then a temperature sensor will inform the control unit if the oil gets to 110C in order to start the fan in slow speed. High speed will be called if the oil gets REALLY hot, around 125C ! The top marking on the oil temp gauge is around 150C, next down approximately 120C, so any reading above 9 o’clock on the gauge should have the fan running without fail.

The A/C Condenser fan should start in slow as soon as A/C is turned on, trigger for high speed unknown (to me at least).

The usual failure is for the fans to only run in fast – this evidences itself with the fan kicking in for just a few seconds when the oil (or refrigerant) is very hot. Unless you sit in traffic regularly you may not experience this, but basically it allows either system to get too hot before something is done about it.

Fortunately, you don’t need a Bosch ‘Hammer’ or a BSc in Electrical Engineering to check the system. The oil cooler fan is controlled by relay R04, A/C by R14 – these are in the fuse box above the RHS of the fuel tank. The photo shows R14 in, R04 removed (white socket). Note that Porsche sourcing still includes VW parts bins !

 

The quick check is to test fan operation by simulating the hot conditions - remove both relays, and then take the cap off one, as in the picture below. Easily done by just easing the tabs out…. there are actually two relays inside, the top one for slow speed (fan in series with resistor), the lower one for fast (12V across fan, no resistor).

 

The relays are identical, so re-install the disrobed relay in either socket – the oil cooler one is the RH socket (from the front). Now find yourself something to prod with (I used the other end of an artist’s brush) – and switch the contacts over. A relay is just an electrically operated switch, and the pic shows the contacts, which change over when the relay is energised. So you just have to do the energising – the circuit is live without ignition. For low speed, insert your prod under the plate the contacts are mounted on, and lift slightly until you see the contacts change over. You should hear the fan start - it’s not quiet, even in slow. For the high speed test that relay is mounted with the contacts towards you, so just push your prod against the relay contact plate. A minor hurricane should occur near your foot ! 

Now remove the bare relay, insert in other socket, and repeat the test.

If fast works but slow doesn’t, its 99% sure your slow speed resistor is toast. With an ohm-meter (DVM) you can measure the circuit – with relay removed, measure between 5 and 7 on the appropriate socket. Yes I know you can’t see the numbers, but they correspond to 87 and 87C on the relay, which you can see, and then relate to the socket. If you’re still not sure, they are the front centre and left lower contacts in the socket (looking from the front). Do be careful, as some of the socket contacts have 12V on them (2&3) and you could hurt your meter or a fuse. The resistance should be <1 ohm, my nice new ones are around 0.7, where they were >1K ohms before.

I got OPC Silverstone to do mine under warranty - it took them 2 hours, including a good ‘hammering’ to confirm my diagnosis, but I suspect they have done a few ….. happily they were able to fit me in before my trip to Goodwood and consequent long periods in traffic. An OPC or specialist should be able to diagnose this without heat soaking the car – so make sure you tell them not to do it!

Some quick and easy places to look for oil leaks

1) under the oil filter tower - requires 4x O-rings to reseal, and usually causes deterioration of the heater hose return line, which can rupture and lose your coolant, causing an overheat.

2) Oil Cooler (front mount) - you didn't state whether yours is a GSL or SE, but the front mount coolers often have problems with broken line bungs, resulting in oil leaks under the left side of the oil cooler.

3) Oil Cooler Lines - again for front-mount oil cooler cars, the lines can get old and crack internally, causing the cloth fabric covering to get oil soaked and leak - fix soon, or you're risking decreased oil pressure and overheating.

4) Oil Pan gasket - along the bottom of the engine, the oil pan is sealed using a 3mm bead of gasketseal, and then bolts are torqued down to 14 ft/lbs - very light torque. This can lead to oil pan leaks and will be evident through gritty oil residue on the pan and transmission bell housing.

5) if you have a lot of oil leaking from the transmission bell housing (front edge or starter mount), you may have the dreaded 'tension bolt leak' which is caused by the O-ring at the head of each of 18-20 tension bolts that sandwich the engine sections. These leak into the space occupied by the clutch and transmission front cover, resulting in a slipping clutch and oil leak from what appears to be the transmission.

Another common oil leak spot is the oil metering pump. It's located on the right side of the engine down low in front of the exhaust manifold. The lines get brittle and sometimes break and the seals inside the pump dry and leak as well. A rebuild is cheap and easy.

Oil pan gasket pretty common, as well as the oil injection tubes. Oil cooler lines usually begin to seep around 100,000, and will either get a little worse, or break. The crush washers on the banjo fitting on the rear housing oil cooler line will also leak. The cheapest, easiest fix is the oil filter stand o-rings, located below the oil filter. Very common, and if they've not been done, likely are leaking now. If the upper front rotor housing is oily, the internal o-rings around the tubular dowels are bad. This is not an easy fix. The engine must be removed in order to repair. The oil coolers are not prone to leak on that year model.

For more information, please visit: http://www.heatecholdings.com/

ASAC REFRIGERATION DIVISION OIL COOLING SYSTEMS

With reference to screw compressor oil cooling systems sales & service engineers should be aware of what methods can be used, how & where to apply & design them. There are three basic oil cooling systems.

•    Water cooled
•    Air cooled
•    Refrigerant cooled

1) Water cooled

Are applicable to systems utilizing Evaporative condensers or cooling towers or where an independent water supply is available.

Water cooled oil coolers are shell & tube or plate heat exchanger design. Generally the oil cooling circuit is on the shell side and the water circuit on the tube side for shell & tube coolers. For PHE's the oil cooler cassettes should be welded & the water side gasketted to facilitate cleaning.

The water circuit on a S&T cooler will normally be 2 pass and the heads or bonnets should be able to be removed for tube cleaning & maintenance purposes. For all applications in Saudi Arabia the tubes + tube sheets should be 90/10 Cu/Ni & the channels or bonnets epoxy coated. Tubes must be straight bore thick wall 0.35" thick, internally enhanced tubes should not be used.

The water circuit can be piped from one end of the pan & back to the opposite end of the pan to ensure thorough mixing of the pan water, using optional extra connections provided by the manufacturer + a separate circulating pump & Y type strainer. Alternatively & probably lower cost option, is to request the condenser manufacturer to provide a "Tee" piece in the spray water pump discharge & uprate the spray pump flow rate + head to accommodate the oil cooler. The water is returned to the spray sparge inlet connection on the condenser. Service stop valves must be included in the flow & return to the oil cooler + a bypass valve between the flow & return located in the standard condenser water pump discharge piping. As the oil cooler circuit will always have the highest pressure drop this bypass valve should be a flow regulating type valve so the flow can be adjusted to the condenser spray manifold with the remainder passing direct to the oil cooler.

Care must be taken in selecting the Evaporative Condenser as the  evaporative condenser or cooling tower sees the oil cooling load as an addition to the compressor THR by virtue of the rise in spray water temperature, unless the water source is independent from the compressor condenser. Generally the rejection capacity will need to be increased by approximately 5% to cover the increase in the spray water temperature. Rather than waste time calculating the rise in spray water temperature just simply include the oil cooling load in the THR figure or select the condenser as normal e.g. evaporator load + shaft power only, but ensure you use a selection with say +10% spare capacity or surface area.

2) Air cooled

Can be utilized on all systems where air cooled condensers are utilized or a water supply is not available. For air cooled systems where the condenser is close coupled to the compressor an additional independent row can be added to the main condenser with its own inlet/outlet header. However sales should contact both the condenser manufacturer to ensure they can provide this facility + the compressor manufacturer to check the engineering & whether a full time lube oil pump is required.

Alternatively a packaged air cooled oil cooler can be mounted on the compressor & the compressor manufacturer should be able to provide a quotation for both the air cooled cooler + mounting & piping.

For all remote air cooled oil cooler applications the oil cooling load is not to be included in the compressor condenser selection. Obviously safety relief valves will be required between any valves in the system & a separate DOL starter contactor or relay, fuse & control circuit will be required for the fans.

3) Refrigerant cooled

Refrigerant cooled oil cooling can be
•    Liquid injection either low or high or automatic low & high Vi into the compressor rotors.
•    Thermosyphon shell & tube or plate heat exchanger
•    Pumped circulation

3.1) Liquid injection oil cooling

In the case of liquid injection the oil cooler load must be included in the THR for the condenser selection. It does provide a low cost means of oil cooling on bare compressor units + chillers. If liquid injection is used, automatic dual Hi/Low injection systems must be used which facilitates injecting earlier or later along the length to the rotors depending upon the operating Vi.
However liquid injection should be avoided wherever possible due to

•    Inability to accurately control the liquid injected at various Vi's & condensing pressures during normal operation.
•    Increase in power + decrease in capacity
•    Problems arising in high back pressure applications where the total mass flow is too high for the radial + axial discharge ports, particularly at pull down.
•    Propensity to cause additional wear in rotors & bearings due to overfeeding or overcooling, causing gas to condense in the discharge ports + oil in the separator.

3.2) Thermosyphon oil cooling

Thermosyphon systems provide the optimum oil cooling system in terms of cost, performance & maintenance. However it is important the system is designed properly and a basic understanding of the system requirements is appreciated. Thermosyphon oil cooling systems may utilize either shell & tube or welded Plate heat exchangers. In all cases the oil cooler load has to be included in the condenser total heat of rejection.

•    Sufficient liquid reserve of 2 minutes must be provided to ensure a continous feed to the oil cooler when the compressor is disabled to allow adequate oil cooling during the motor coast down period.
•    Thermosyphon systems must operate with a liquid overfeed rate of minimum 1.5:1 to 4:1.
•    The liquid feed and wet suction returns have to be very carefully sized to reduce friction losses to a maximum of 0.5pfsi/100' (0.035 kg/cm2) for the liquid feed & 0.2pfsi/100' (0.014kg/cm2) for the return. If the line sizes are too small the friction losses  will increase. As the friction losses increase the circulation rate will reduce; the flow will balance out at a new equilibrium corresponding to the static head minus the system pressure drop.
•    Wherever possible the main system HP liquid receiver should be used rather than using pilot receivers.
•    In terms of static head, the liquid feed static head must be high enough to overcome the pressure drop in the liquid feed + oil cooler + return line. Generally the total pressure drop will be around 1.5pfsi which requires the priority vessel to be mounted at least 2mtr above the TSOC/s.
•    For multi TSOC applications a plug type flow regulating valve must be installed at the inlet to each TSOC to enable proper balancing of the flow. Normal service stop valves or ball valves or butterfly valves are unsuitable for flow regulation & should not be used.
•    Where the main system HP receiver is used or where a priority or pilot receiver is used for single or multi condensers in parallel, the vessel must be installed at a height of at least 6mtrs below the condenser outlet drain in order to ensure free liquid drainage as per the sketch provided to you all previously. The priority or pilot or main HP receiver must be vented back to the condenser inlet connection. To calculate the correct trapping height of the condenser liquid drain lines, the pressure drop must be calculated from the condenser hot gas inlet to the vessel. This averages out at around 5-6psi & @ 40degC liquid temperature (1ft head = 4psi @ 40degC) the drain line trapping height will approximately 6mtr.     Too much height is preferable to little height. If insufficient height is allowed, liquid will back up in the condensers until sufficient static head is available to overcome the drain line pressure drop.
•    Liquid drain service stop valves must be installed in the vertical position above the drain trap into header back to the vessel at a height of at least 1.2mtr above the P trap.
•     Thermosyphon circulation is no different from a mechanically pumped system except that the motive force arises from the conversion of kinetic energy to pressure energy by virtue of the difference between the available static liquid head minus the circuit pressure drop & by the difference in density between the single phase liquid feed & the 2 phase liquid/vapour return. However unlike a mechanically pumped system or pumper drum system, thermosyphon systems are fixed head systems & cannot pump to a height above the available static head except for small differences between the flow and return due to differencies in refrigerant density plus Einstein bubble lift effects where gas bubbles lift the liquid as they rise through the column.

             If the pressure losses through the TSOC + return line are greater than the available liquid feed static             head, then liquid overfeed cannot take place The TSOC will then act as a flooded cooler on a 1:1 basis & a danger of gas binding arises.

             The TSOC/s return line/s must be larger than the liquid feed line by one pipe size to accommodate the vapour return & ensure friction losses are maintained at or below 0.2psig to ensure the design 4:1 recirculation rate is achieved. The vapour is carried back with the liquid by the force exerted by virtue of the static head & refrigerant liquid density difference + Einstein bubble lift flow. The vapour velocity may be greater than the liquid velocity but it is not necessarily the case that the vapour velocity is sufficiently high enough to assist in the liquid return up vertical risers and back to the priority vessel.

             The return flow in a vertical riser on a TSOC is not the same as a wet suction return on a freezer cooler,  where the circulating pump is designed to circulate the design refrigerant mass against the pressure differential between pump suction & surge drum return connection for bottom fed coolers below the surge drum, or to the cooler outlet connection for top fed coolers above the surge drum where gravitational forces

             assist in returning the liquid & vapour.
             The flow regime in a thermosyphon vertical riser or pumped cooler system will be 2 phase Annular, bubble or slug flow depending on the heat flux, liquid/gas velocities, pipe size.
             In case of pumped liquid overfeed systems or gravity flooded systems, the vertical riser pipe size may be smaller than for a TSOC application & the systems must not be confused. In the case of long vertical risers if the pipe size is larger than necessary the static head will increase requiring higher head pumps or in the case of Thermosyphon flow, stalling of the thermosyphon cycle.
•    Where for some reason the TSOC return/s cannot be headered back to the pilot or priority vessel & are taken up to the condenser hot gas inlet pipe, it may be impossible to obtain liquid overfeed or a 4:1 rate of recirculation as there is insufficient static head or kinetic energy to drive the liquid above & beyond the liquid level existing in the priority vessel.

•    The thermosyphon circuit is simply a closed loop U tube, where, when no heat is rejected in the oil cooler, no circulation will take place & the liquid level in the liquid feed & return line will be in equilibrium at the same height, as the pressure above both the feed & return in the priority vessel will be at the same saturated pressure as exists in the condenser. The liquid temperature will be the same as the condenser saturated temperature by virtue of the vent lines from the HP receiver + the priority vessel, back to the condenser inlet.
•    The phase change from liquid to vapour in the TSOC will be at a higher temperature than the condensing temperature due to the submergence effect in the oil cooler due the static liquid head pressure exerted by the liquid feed line + vessel diameter. This provides the difference in refrigerant liquid density due to the difference in temperature. The refrigerant flow rate can be calculated by the TSOC THR divided by the difference in enthalpy between the liquid & vapour at the condensing temperature e.g. 40degC x by the recirculation rate.
•    A common misconception with thermosyhpon oil cooling systems exists in relation to taking the TSOC return back to the priority vessel, where Sabroe recommend against it due a loss of liquid subcooling.
•    They recommend the returns are taken up to the condenser inlet line. The notion of loss of subcooling is incorrect (In Saudi Arabia) as the liquid exiting the condenser & the liquid in the priority vessel + HP receiver  will all be at the same saturated condensing temperature e.g. 40degC by virtue of the gas balance or vent lines.
            Too, as explained above there will be insufficient motive force in the TSOC liquid feed line or liquid density difference to force the liquid refrigerant up the portion of return line above the liquid level in the priority vessel. In most evaporative condenser designs, the hot gas inlet connection will be approximately 1.5mtr above the outlet connection & upto 6mtrs above the priority vessel liquid level.
            If condenser sub cooling is required then the condenser has to be ordered with a separate sub cooling
            section with its own inlet & outlet connections separate from the condenser main inlet & outlet
            connection. The liquid to the system is then fed from the HP liquid receiver through the condenser sub
            cooling coil and from the coil to the system.
•    Priority or pilot receivers are additional expense in terms of the vessel + installation costs. Wherever possible the main liquid receiver should be used to feed the TSOC/s. Generally there is little maintenance required on a receiver & if external liquid level gauge glasses are used there is no reason on any installation why the liquid receiver should not be installed in the plant room, out of the sun, installed at a height of 2 mtrs above the TSOC/s. The receiver should have a priority pot on the outlet sufficient to provide 2 minutes of liquid storage which is the amount of time for the motor/compressor to coast down to zero RPM. As noted above it is very easy to calculate the liquid overfeed flow rate in Kg/s or lbs/min and from that to
            calculate the priority pot capacity in M3 or ft3 by multiplying the 2 minute supply by the density of the
            refrigerant at the condensing temperature.
            If liquid receivers are installed on the roof along with the condenser then insufficient trapping height will be
            available, unless  a bottom inlet surge type receiver is used, plus the receiver will be subject to excessive
            heat ingress due to solar radiation whereby surface temperatures have been logged at upto 80degC.

3.3)  Pumped liquid recirculation oil coolers

           Pumped recirculation oil coolers may use Shell & Tube or Plate heat exchangers. Liquid is circulated using a  mechanical hermetic pump at a rate of  1.5 to 4:1. This system would generally only be used where insufficient static height exists to install a priority or pilot receiver or the main HP receiver cannot for some reason be elevated at least 2mtr above the oil cooler/s & refrigerant cooling is the only option available. Obviously the system is expensive in terms of initial capital costs of the pump, starter, controls, orifices, valves, strainer, relief devices etc, in comparison to a straight Thermosyphon system.
•    The refrigerant mass flow rate is calculated in the same way as detailed above e.g. Oil cooler THR/ enthalpy difference between liquid & vapour @ condensing temperature x the rate of recirculation e.g. x 4.
•    The oil cooler should be selected on whatever rate of flow provides the smallest heat exchanger, commensurate with the lowest pressure drop. If it is the same size cooler or same # of plate cassettes there is no point in selecting a recirculation rate of 4:1 if 1.5: 1 provides an identical cooler.
•    The pump should be connected to an outlet connection on the main system HP liquid receiver ensuring the receiver is mounted at a height sufficient to meet the pump NPSH requirements. The return from the oil coolers can be taken back to a connection at the top of the HP liquid receiver.
A suitably sized vent line based on the mass vapour flow must be installed between the receiver & the condenser inlet. The vent or gas balance line would be selected based on the mass flow rate and pressure drop of less than 0.2pfsi100'.

Trail Bikes Oil Cooler Kit Installation Guide (Part II)

 

Step 3.  Remove the right hand side cylinder head cover (it is the one near the spark plug held in with 3 bolts) The center bolt runs all the way through the head to the other side, hold the cover on the opposite side when removing the long center bolt.

Once the head cover is removed, remove the old gasket and clean off any oil from the sealing surface on the head.

At this time select the new gasket from the two that are provided in the kit.  You need to check the gasket against the head plate to see which one aligns with the holes and passages on your application.
Next, prepare the oil cooler taps to be installed into the new head tap plate provided with the kit.  You will need to use the Teflon tape provided in the kit on the threads to ensure an oil tight seal as the illustration shows below. It is not necessary to use Teflon tape on the compression fitting side of the taps.  Make sure when wrapping the threads with the Teflon tape that you are applying the tape in the same direction as the taps would thread into the new head tap plate.  The tape should cover the threads of the taps but it must not cover the end where oil will flows through.

 

Prepare the new oil cooler head tap plate to replace the right hand side cylinder head cover by installing the oil cooler taps. Pay close attention to the angle you have installed the taps to ensure they are facing in the direction that you selected when “mocking up” the install in Step 1.  Be sure not to over tighten the taps. Make sure that the taps are in such a position that when attaching the oil cooler line that the lines clear the cooling fins on the new head tap plate. Minor adjustments of the taps can be made once everything is in position.



Step 4. Ensure that all sealing surfaces are clean and apply the gasket of choice. Install the head tap plate on the engine and torque the bolts to manufactures specification. The torque rating is 8ft lbs for a factory Honda engine. Once the head tap plate has been installed, proceed to step 5.

 

Step 5. Route oil lines to the oil cooler and head tap plate. At this time only hand tighten the lines and determine what the best routing for your application will be.  You may have to make minor adjustment to the taps to achieve the best routing for you application. It is crucial to ensure that there is no severe bends in the oil lines that could restrict oil flow.  The lines must attach to the cooler at a nearly perpendicular angle (90’ angle) or else the banjo fittings will not form a seal.  If not installed at a perpendicular angle the end of the line will bottom out on the cooler and not the sealing surface for the banjo fitting. Once you have determined the correct routing for your application then tighten all connections.

 

Step 6. Check over complete installation to ensure that all lines are routed without severe bends and that all connections are tight.  Turn the wheel lock to lock and compress the suspension fully making sure nothing will come in contact with the cooler or the lines. Check the oil dipstick to make sure the oil level is full. You are now ready to start your engine.

 Start the engine for a few seconds (10 seconds or so) and inspect all connections for any signs of leakage.  Shut the engine off after the 10 second interval.  Oil pressure should have built up and some of the oil should now be in the cooler causing your crankcase to be low on oil.    If it does not appear that the oil level has decreased any there may be an oil flow problem and severe damage could occur if engine is restarted.  Recheck all connections and installation if the oil level in the crankcase is not dropping.  If the oil level lowered by a few ounces add the necessary oil to bring the crankcase oil level back to full. Once the oil level is back to full and you have made sure that there are no leaks, start the engine and allow it to run for a little longer and then shut off the motor and verify oil level again.  Do this a few times until the oil level stays consistent, resulting in the correct level for the new increased oil capacity with the addition of the new Trail Bikes oil cooler.

Step 7. Recheck all oil connections, mounting bracket of choice, cylinder studs should be re-torque if you chose this mounting method, re-torque cylinder head cover and check for oil leaks once again.  If everything looks good, proceed to start the engine again. After the engine has warmed up you should be able to feel some warmth by touching the oil cooler. At this time rev the engine up a few times and ensure that there are no oil leaks again and again.

If the installation was performed correctly the cooler will provide very reliable service, extend the life of your engine and increase the performance on long or heavy-duty runs that generate a lot of horsepower robbing heat.

IMPORTANT NOTE

If you would like to verify that the installation is correct and that the oil is flowing as it should (highly recommended when installed on non OEM Honda engines such as the popular Chinese produced replicas)  please take the following steps.

You will need to check for oil flow and pressure in some critical areas of the engine.  First check for oil flow through the cooler.  The easiest way is to crack loose the fittings on the cooler, check one at a time and shield the oil from hitting you with a rag as the oil can just squirt out (do this at your own risk)  If there is oil pressure escaping at each end of the cooler then you can be certain that the flow to and through the cooler is good.

Next you want to make sure that the cam is getting oil to it with the new cylinder head cover (this is particularly important to check on Chinese replica engines with the “short” cam as the boss on the Trailbikes cylinder head cover does not extend as far as the factory Chinese cylinder head cover)  You can remove the top cylinder head cover and look for a large amount of oil on the camshaft lobes and rocker arm area.  You can also remove the cylinder head valve caps and see if oil squirts out of the rocker studs (once again, perform this check at your own risk as hot oil will squirt out under pressure if everything is installed correctly)

Recheck the oil level as you are sure to lose some performing these checks and then start enjoying your bike again knowing that the power won’t drop off as much after you ran that motor hard like it did when it was just air cooled.

For more information, click here.

Trail Bikes Oil Cooler Kit Installation Guide (Part I)

The Trail Bikes Oil Cooler Kit is a high quality accessory designed to help your Honda horizontal engine or Honda clone engine keep cooler.  Air-cooled engines run hotter when modified or subjected to heavy loads such as racing use.  This kit will help your engine’s durability and reliability by circulating the engine oil through a cooler reducing the engine’s oil temperature.  It is highly recommend that you completely read through the installation instructions before you begin.

WARNING!!!
The installation of aftermarket accessories such as this oil cooler kit may void your manufacturer’s warranty. Trail Bikes is not responsible in any way for such voids.

WARNING!!!
This guide is for illustration purposes only.  All engine work should be performed by a trained professional mechanic and in accordance to factory recommendations.  Improper installation could result in extensive engine damage.  Use this guide for reference only.  Any and all instructions provided are suggestions for the professional mechanic.

 


Step 1.   Remove oil cooler from box and examine the two mounting brackets included in the kit.  The bracket attached to the cooler is made to slip over your cylinder studs as the illustration shows above.
The other bracket is designed to attach to the frame as the illustration shows below.  The brackets provided in this kit are designed to work on multiple applications and you will need to determine what works best for your application.  If you have the option to use either on your application, we recommend using the frame mounted bracket setup.

 

It is best to locate a spot on the bike that is towards the front of the bike where air will travel across the cooler as the bike is traveling forward.  Once a good spot has been located, attach your mounting bracket of choice. Only hand tighten the cylinder studs or the hose clamp provided for the other mounting bracket.  At this time you will  “mock up” the installation and make sure that the oil cooler lines will be long enough to reach the cooler and that the lines will not have to make any extreme bends which would restrict oil flow. (Please note that the cooler can be installed upside down if necessary, the oil lines can be at the top or bottom of the cooler)
Turn the wheel lock to lock and compress the suspension fully making sure nothing will come in contact with the cooler or the lines.
If everything looks like it is going to clear, proceed to step 2.



Step 2. Mount the oil cooler in the selected location using the mounting bracket of choice.  The illustration above shows the cooler being mounted with the bracket that slips over the cylinder studs.  Be sure to re-torque the cylinder studs to your manufactures specification if you choose this method.  The torque rating is 8ft lbs for a factory Honda engine.

The illustration below shows the oil cooler mounted to the frame using the other bracket provided. This mounting bracket is attached to the frame using a hose clamp and is the better choice if it can be used on your application.  For a stronger and more reliable mount you can also drill and tap a hole in the frame.  The bracket has a clearance hole in it already. This would be the preferred mounting method if applicable.