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Question about pressure relief valve on FT500 Hale on Deuce and a Half fire truck

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  • Question about pressure relief valve on FT500 Hale on Deuce and a Half fire truck

    The original mechanical Hale pressure relief valve with visual pressure relief activation indicator was replaced with a later model Hale control valve, but this one does not have a visual activation indicator. All seems to be working fine, but I cannot tell when the pressure relief is working. I figured that if I T into the line that goes from the pressure relief control valve to the pressure relief valve I could place a pressure switch that would illuminate a lamp if pressure is present activating the relief valve. Since this is a transfer case pto driven midship pump, engine life should be extended by controlling rpms as well as pressure and this light would assist in determining if I have enough pressure/flow at a set rpm. Also would help diagnose faulty or sticky pressure relief valves.

    If my concept is correct, what psi should I expect to see in this line when activated? Any suggestions?

    Any input would be appreciated.
    Thanks
    Raul

  • #2
    Pressure switch in the control line from the pilot assembly to the main relief (churn) valve won't work as an indicator. When the pilot assembly valve is set higher than the discharge pressure of the pump, the pilot valve is closed and no flow comes from the pilot to the churn valve operating piston. However, there is an orifice that passes through the operating piston and goes directly to the intake side of the pump. Your Idea would work if you were always at draft, but the minute your pump is supplied from a pressurized source (positive intake pressure) the pilot line pressure will increase by back feeding water through the orifice and raising the pilot line pressure until it matches intake pressure. Most Hale relief valves have a place to install a microswitch in the churn valve case with a spring that will cause the switch to close if the piston moves and the churn valve is open.

    Comment


    • #3
      Originally posted by KuhShise View Post
      Most Hale relief valves have a place to install a microswitch in the churn valve case with a spring that will cause the switch to close if the piston moves and the churn valve is open.
      Thank you for the reply, you may have saved me a lot of effort that would have been for naught. I have dissassembled the pressure relief valve looking for such a place, but all it is a cast bronze "hat" with a 3/8 port in the center (going to the output of the pressure relief valve control) and a smaller (3/16?) on the side going to the combined drain valve. As I mentioned, the original pressure relief valve control had the mechanical visible actuation indicator in the control valve, it was replaced with a newer model that has no such indicator and the indicator is meant to be electrical and mounted on the pressure relief valve.

      What about having a checkvalve between the pressure monitoring point between the control valve and the pressure relief valve, allowing flow only in the direction of the pressure relief valve?
      Thanks again
      Raul

      Comment


      • #4
        scooter:
        Search for the manual that was returned after the modification. Determine the exact model and if possible serial number of the replacement relief valve. Armed with this knowledge, call the Customer Service Dept. at Hale. Phone 610-825-6300
        The drawings I'm looking at seem to have the same body casting, but the end cap is different. Hale will be able to make suggestions.

        Having made this suggestion, I do not believe the "Idiot light" is a real necessity. Simply follow either of the following procedures: Get a line off and operating by throttling up to 10 psi above the desired pressure. It may be necessary to increase the relief setting if it is too low initially. Reduce the relief setting until the discharge pressure just starts to drop, but is still above the desired discharge pressure. Last, reduce the RPM until the pump pressure drops to the correct pressure. Now the relief will be correctly set. If you need to add a second line, the pressure will drop requiring an increase in the throttle, but do not reset the relief valve if both lines require the same operating pressure.
        Second way is to throttle up to the required pressure. Reduce the relief valve setting (slowly) pausing for 10 or so seconds between adjustments, until the discharge pressure starts to drop below the desired discharge. Raise the relief setting about 1/2 turn above the point where the discharge is correct.
        With two or more lines operating and a line is shut down, the relief will hold the pressure at the set point. Test this by reducing RPM until you see the pressure drop below the desired PDP, then raise the rpm slightly. If the PDP requirement doesn't change, it should only be necessary to adjust the throttle to compensate for changes in actual discharge pressure. Your goal is to run as low an rpm as possible and still maintain the correct PDP.

        Comment


        • #5
          Thanks Kuhshise
          I have spoken with Hale, but since this pump is almost 40 years old, they have little information regarding it (I guess they never expected their pump to still be in use after all these years)-Plus, this system is mounted in a military truck, so may be truck specific up to a point. Thank you for the info for setting it. I will contact Hale again tomorrow with this specific question. At least I have the comfort of knowing that it can still be used as is. The local firehouse will assist in backwashing and actually pressure testing the truck from a hydrant.

          Maybe you can help in a different matter. Seems that when pumping from the 500 gal tank, through a 2.5 inch valve, when I try to use the stang nozzle w a 1" opening, I cannot build more than 50 psi. Could it be that using that nozzle requires that the truck be fed from the 4.5 intake? with the 2 - 1.5 in hand lines I can get up to 150-180 psi pressure built up and then use the rpm's and the pressure relief valve to bring it down to a more manageable 80-100 psi- Thank you again

          Comment


          • #6
            Scooter: If you are going to fight fire with this old BEAST, you need to learn about friction loss in hose and nozzle flow. A 1-1/2" combination nozzle is usually around 100 gpm, and requires 100 psi of pressure for correct operation. A 200 ft line of 1-1/2" hose at 100 gpm has a friction loss of about 45 psi, so your correct pump pressure would be around 145 psi. absolute. (-14.7 psig) Operating 2 preconnects like this requires a flow of 200 gpm from the tank to the pump.
            The age of this engine and the likelyhood that a 2 1/2" line was used between the tank and the pump, probably limit the flow to around 250 gpm. This arrangement will supply both 1-1/2" lines, but when you try to supply a deck gun, the flow could be considerably more that 250 gpm. A 1" tip at 50 psi flows 210 gpm; Raise the nozzle pressure to 80 psi and it flows around 270 gpm. Next std. size tip is 1 1/8 with flows of 265 and 341 gpm. respectively.
            The amount of water that can flow from the tank to the pump is limited by the air pressure of 14.7 psi. As you approach a perfect vacuum, water will change from a liquid to a gas (water vapor), so you will never reach a pressure of zero psi. Therefore there will never be any more pressure available to get the water from the tank than that. You do not want to operate this pump under cavitation because you can destroy the pump. A creeper and a flashlight will allow you to take a look at the actual piping between the tank and the pump.
            Last edited by KuhShise; 11-09-2010, 06:57 PM.

            Comment


            • #7
              The deuce.... an old beast? Wow... that hurts!!

              Hi KuhShise

              Offended? Nah, just kidding... I am a believer that it is easier to keep these earlier all mechanical trucks on the road for a far longer lifetime than the cool new ones... Don't get me wrong, I appreciate the capabilities of the new ones, but my company cannot afford to either buy one or maintain one. Our main goal is to be a "first responder" to our business needs and assist the more remote locales as needed. Anyway, she sure looks good putting water out.

              Thank you for clarifying many concepts that the locall FD friend and driver has spent time with us addressing. I agree with...you need to learn about friction loss in hose and nozzle flow. A 1-1/2" combination nozzle is usually around 100 gpm, and requires 100 psi of pressure for correct operation. A 200 ft line of 1-1/2" hose at 100 gpm has a friction loss of about 45 psi, so your correct pump pressure would be around 145 psi. absolute. (-14.7 psig) Operating 2 preconnects like this requires a flow of 200 gpm from the tank to the pump.

              The age of this engine and the likelyhood that a 2 1/2" line was used between the tank and the pump, probably limit the flow to around 250 gpm. This arrangement will supply both 1-1/2" lines, but when you try to supply a deck gun, the flow could be considerably more that 250 gpm. A 1" tip at 50 psi flows 210 gpm; Raise the nozzle pressure to 80 psi and it flows around 270 gpm. Next std. size tip is 1 1/8 with flows of 265 and 341 gpm. respectively.

              This really crystallized one of the issues...
              ...The amount of water that can flow from the tank to the pump is limited by the air pressure of 14.7 psi. As you approach a perfect vacuum, water will change from a liquid to a gas (water vapor), so you will never reach a pressure of zero psi. Therefore there will never be any more pressure available to get the water from the tank than that. You do not want to operate this pump under cavitation because you can destroy the pump. A creeper and a flashlight will allow you to take a look at the actual piping between the tank and the pump.[/QUOTE]

              Been there... definitely the water going from the tank to the pump goes through a 2.5 in valve... having hooked up the truck to a dry hydrant I was able to build over 150-180 psi on the deck gun and have a sizeable stream... over 100+ feet through the 1" nozzle...

              then something happened... a shop mechanic noticed the packing getting very hot and that it was not dripping... he loosened it some.... still no dripping... loosened it some more... Lost all Pressure.. never got it back... I can get a good prime, but cannot build pressure again... we did not run for more than 5-10 minutes... so I hope we did not screw up something major... sorry if we sound ignorant... if we do, it is because we are... I do appreciate all of your help...

              any hints on adjusting a packing? Really hope we did not cook it... it costs about 200 bucks... or worse!

              thanks again

              Raul

              Comment


              • #8
                OK, the packing gland is fed by a small 1/4" line that brings high pressure water from the pump discharge (volute) into the packing directly on top of the lantern ring. The lantern ring should have 1 or 2 packing rings between it and the pump casting, then there should be about 4 rings between the lantern ring and the split packing ring compressor. Really need the right pump drawing / manual to be sure. Connect to a pressurized source (garden hose) and fill the pump with water. Disconnect the small line at the packing gland and make sure there is water coming through the tubing. With an old rig, sometimes people just add packing rings without removing the old ones. This eventually forces the lantern ring forward until the water from the tube can't get through the ring to the shaft. 10 drops per minute is the absolute MINIMUM and I prefer having a thin stream or a lot of splatter going on under there. With a 4 1/2" hard sleeve, this is probably a 500 gpm pump with a sleeve bearing on the front of the pump. Be sure to check the oil in the bearing reservoir. Hale made a change about 1970 and began using a diaphragm pressure balancing system on this end. If the oil is contaminated with water, it might require replacing this diaphragm. I didn't mean to offend you. Here in the Great Buffalo Swamp of the Seneca, we have hills with 30% grades and these old war horses still growl their way up logging roads and pipe lines every spring for brush fire season. Sometimes lugging 2,000 gal. of water where the deer won't travel.

                Comment


                • #9
                  Disclaimer: I only have 2 pumpers with hale pumps on them, and they are circa mid/late 90's vintage.

                  With that said, I need ALOT of information concerning what you have now for your PRV (Pressure Relief Valve). Need to know what you have now, as in part number, and anything else you can give me. This includes the pump its self, what model and year.

                  Does this newer PRV have a 1/8 NPT capped port in the valve??? If so, it could be possible to install a 5 psi normally open pressure switch in its place. When the valve opens, and sees 5 psi, it would close, and turn on your indicator, showing that the valve has opened. This is purely a guess, for now.

                  @ Kuh..
                  Most Hale relief valves have a place to install a microswitch in the churn valve case with a spring that will cause the switch to close if the piston moves and the churn valve is open.
                  Is this somewhat similar to how the waterous systems work, with a microswitch on the end of the relief valve its self?? Where at .010 it is off, and .015 it is on???

                  I think I'm over my head on this one, but I'll help as much as I can.

                  FM1
                  I'm the one Fire and Rescue calls, when they need to be Rescued.

                  Originally posted by EastKyFF
                  "Firemens gets antsies. Theys wants to goes to fires. Sometimeses they haves to waits."

                  Comment


                  • #10
                    HALE PUMP INFO:
                    Hale fire pump
                    GSAL
                    Model No. GS-16-9.5
                    serial no. 34301

                    Cannot find the 1/4 inch line you speak of. This is a pic our backup pump and the diagrams hale had on hand. Also included the primer.

                    Here is a link to the youtube video showing the gauge panel while pumping. I just read in the manual that if I am showing a vacuum in the compound gauge while drafting, I am exceeding the capacity of the water supply...

                    http://www.youtube.com/watch?v=r06X2XcYnbM

                    and shooting water

                    http://www.youtube.com/watch?v=ihOHmbvX04c

                    thanks ... help is definitely appreciated

                    Oh yeah... I know... pump panel tach is not working... working off engine tach and it is turning about 1600 rpm

                    Raul

                    Originally posted by KuhShise View Post
                    OK, the packing gland is fed by a small 1/4" line that brings high pressure water from the pump discharge (volute) into the packing directly on top of the lantern ring. The lantern ring should have 1 or 2 packing rings between it and the pump casting, then there should be about 4 rings between the lantern ring and the split packing ring compressor. Really need the right pump drawing / manual to be sure. Connect to a pressurized source (garden hose) and fill the pump with water. Disconnect the small line at the packing gland and make sure there is water coming through the tubing. With an old rig, sometimes people just add packing rings without removing the old ones. This eventually forces the lantern ring forward until the water from the tube can't get through the ring to the shaft. 10 drops per minute is the absolute MINIMUM and I prefer having a thin stream or a lot of splatter going on under there. With a 4 1/2" hard sleeve, this is probably a 500 gpm pump with a sleeve bearing on the front of the pump. Be sure to check the oil in the bearing reservoir. Hale made a change about 1970 and began using a diaphragm pressure balancing system on this end. If the oil is contaminated with water, it might require replacing this diaphragm. I didn't mean to offend you. Here in the Great Buffalo Swamp of the Seneca, we have hills with 30% grades and these old war horses still growl their way up logging roads and pipe lines every spring for brush fire season. Sometimes lugging 2,000 gal. of water where the deer won't travel.
                    Attached Files
                    Last edited by scootertrs; 11-10-2010, 04:28 AM.

                    Comment


                    • #11
                      Look at your drawing and locate "GS-420" (center - 4th label down) If you have the table identifying each of these items shown on the drawing... see if it isn't a tube to bring higher pressure water from behind the wear ring (pressure side of the pump) across the intake opening and into the cooling passage for the packing. If this is the case, then there won't be any external line from the volute to the packing gland.
                      Yes, it is possible to damage the shaft by having improperly adjusted or spaced packing rings and/or lantern ring in a relatively short time. A total failure without a lot of associated noise is unlikely. Loosening the packing will allow air to enter the pump, and a relatively small amount can prevent a good prime. Having said this, I would still try adapting a garden hose to an outlet and pressurize the pump to city line pressure. You will then locate any leaks, and this might also help to remove the packing rings if it becomes necessary.
                      Check both your compound and master discharge gauges with no pressure on the pump. both should read zero. Empty the pump and leave it out of gear with the engine off, and operate the primer. (If a mechanical primer you will need to have it in gear) You should be able to achieve a vacuum of at least 15 inches (20 is better) on the compound gauge. A properly sealed pump with caps in place and all valves closed and capped should only lose 1" of vacuum per minute over a 10 minute span. Climbing under the rig after having operated the primer, you should be able to locate any significant leaks by listening carefully.
                      When you are operating, the pump is usually running between 2 & 3 times faster shaft speed than the motor. (step up gearing) Yes, shaft damage can occur quite rapidly due to heat, the shaft does or should have a heavy chrome plating under the packing. Try to minimize the dry turning by having made all hook-ups prior to putting the pump in gear.
                      I asked firemech to jump in here because he gets to play with equipment more than I do. As a result, some problems get solved by trial and error, so the more experience one gets the easire the solutions become. I looked carefully at the drawing, but could not locate a label for a diaphragm between the pump impeller and the end bearing. This might be a brass sleeve bearing that is grease lubricated. Take a look in the manual and be sure that both the transfer case lubrication and the end bearing have the required maintenance. Old (1920's) American LaFrance pumps required opening two plugs when greasing the outboard bearings. One to put new grease in and the other to allow the old stuff to come out. If you don't, it pushes the shaft seal back into the pump and destroys the seal.
                      Last edited by KuhShise; 11-11-2010, 10:24 AM.

                      Comment


                      • #12
                        Looking at the operating video...At 180 psi and accounting for small valve openings, elbows and the 10' length of 2 1/2 to the Stang...I estimate about 135 psi at the nozzle. This would be around 350 gpm. Fire pumps are rated at 150 psi for full volume so...500 gpm for your pump. 70% at 200 psi .. 350 gpm and 50% at 250 psi or 250 gpm. Probably close to the rated capacity. You said that you were working from a "Dry" hydrant. This acts like a long suction hose along with the 10' piece of hard sleeve and might be a limiting factor in your tests. Also these dry hydrants should be back flushed periodically to remove debris so it doesn't get sucked into the pump. By the way, does this pump have intake screens at the suction hose connection at the pump? Have your FD guy show you how to back flush this from a city hydrant.

                        Comment


                        • #13
                          Look at your drawing and locate "GS-420" (center - 4th label down)... You are right on the money... that passageway is actually cast into the housing. I will take the packing out and investigate further. I suspect that it is clogged since with the packing nut almost loose it would not leak, but would leak at hydrant pressure (50 psi)

                          Thank you for the help

                          Raul

                          Comment


                          • #14
                            Knowing now that the "newer" pumps have a temperature "thermostatic" bypass to allow bypass when temps are exceeded... Is there a simple way to attach a gauge... like a murphy gauge to the pump housing, that will keep you in tune with temperaures at the packing or in the pump housing... that way if temperatures merit attention, the operator can take proper action... be it opening up a bypass or idling down, or shutting down if an option if in case pump/shaft damage was to accurr. Maybe the murphy gauge would in turn kick in an alarm? BTW, what is an acceptable temperature range for a graphite packing?

                            Thanks

                            Raul
                            Last edited by scootertrs; 11-12-2010, 10:55 AM.

                            Comment


                            • #15
                              I am an old school fireman, learning on pumpers from the 1930's, 1940's and 1950's.

                              No indicator for the relief valve.

                              Either you watched the Master Gauge or listen for the sound of the relief valve kicking in.

                              The modern types with lights, buzzers and the like make life very simple.
                              Stay Safe and Well Out There....

                              Always remembering 9-11-2001 and 343+ Brothers

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