From a pumper...

[speedy]

Hey, there mixer drivers.

I'm a concrete pump owner/operator. I hope you guys appreciate what Matt is doing here. this is a great forum for you guys to gain experience from others in the business. Ask questions, give advise. Give newbies the benefit of your experiences, good & bad, and take something from this forum for yourself.

One thing all pumpers appreciate is if you would top up their water tank , especially if you are one of the last trucks, but check with the operator first, some guys are pretty particular about their iron.

Also it is IMPERATIVE that the hopper be kept relatively full, so that it doesn't suck any air. This can result in some severe injuries or death at the other end, in the event of a plug & release. At the very least it is messy.

Be aware of the location of the Emergency stop in the event that you need to use it, and talk to the operator to find out what circumstances you should use it.

Feel free to post any question you have about pumps, me & my fellow pumpers will do our best to fill you in.


"POUR IT OUT"

[Driver]

Nothing I enjoy more then pulling into site and see a pump truck,,,,,
Dont worry about keeping hopper full,my throttle will do that,just keep your hose moving bro
LOL on the water thing,,,,,We gotta keep our stuff clean also,,,nothing I hate more then to see all the guys washing their boots off,with 70 gals of water running under my truck,and the job aint dumped off yet,,,,
Why dont you guys bring water with ya (lol)
LOL we appreciate Matt alot,,,,,but its for reasons we cant talk about here ;D ;D

[speedy]

I do bring water. In fact, I even have water in the winter. I built a heat exchanger for my tank.

I just like knowing I have a FULL tank, 'cause I like to water-wash.

Water is a pain in the winter, especially if you're traveling out of town. I also have an electric heater on my tank. Used it twice this winter on out-of-town jobs, keeps the water at 100 F. I have a shop to park in.

[budman]

im pretty good about making sure pump operaters have water. i usally have more than enough. if i dont its because i didnt get my load right before leaving the yard! for the most part i will even make sure contractor is all set before leaving the job. i know what its like being on the other end of the chute, its not all that fun,well it can be but ..... i know matt will agree with me on this one all tho we havent had the pleasure of doing a job together, im am sure its not to far off! i like finishing i just dont like setting up! i have done many many many side jobs in my life, but working for someone else doesnt seem to reap the cash! plus i dont like gettin up stiff every morn. lord knows im not getting any younger ive got alot of respect for all you finishers in the feild. oh and lets not forget about the laborers they work pretty hard too. been there done that, cause in order to make the cash you gotta do it all! peaceout


t-bone

[nascarfan67]

well i can understand the pumpers request for water, they like us can only hold so much water, but unlike us, they dont allways get the chance to return to the plant for fresh water, its off to another job, i know this beacause i drove a pumper for awhile, but its nice to pull up tp a pump truck, makes our job very easy, and i dont think its a unreasonable request to have the last truck ask the operator if he needs water, i allways do,maybe beacause i drove one and know how much water is needed to wash them out between every job, hey speedy, maybe sometime ill get the opportunity to tell you about the pumping that went on at metro airport, when they laid the footer for the new terminal, it was the worlds larget non stop concrete pour, over 115,000 yards in 23 hours, was awesome to take part in.

[batchmaster]

sounds like you just told speedy about the job at metro??? what more could be said?

[speedy]

115,000 yds and a crew of 6 Italian finishers. ;D

[batchmaster]

hey, i have heard of the pump backfiring mud out of the hopper like old faithful, what causes this?

[Driver]

Never heard of a backfiring term
But I do know if know if I dont keep mud in his hopper they get a bit upset.....
Stones flying,,, 8-)Boom shaking,,, 8-)guys trying to hang on to the hose,,, ;D ;D... Not a pretty sight for the guy hanging off walls pans 15 ft in the air,,,,sometimes it not so purdy on my windshield either

Have seen em flow back wards tho, I know operator can bring it back into hopper,,Not sure what would cause a backfire,,,some kinda of mechanical failure
This Q is for speedy,,,,,Im just working on getting my post count up

[speedy]

It is caused by the material cylinders sucking air in instead of concrete, it blows a bit of compressed air (from the pressure of the concrete that's already in the pipes) back out of the cylinder at valve change-over....you weren't paying attention, were you? ;~)

I always tell the mixer drivers to keep it at the bottom of the grate, that way there is a bit of room if I stop suddenly. If it's a stiff mix, they need to keep it slighly above the grate. Chute placement helps alot too, there is a 'sweet spot' where the mud will flow well into both cylinders. If you have the chute off to the side, it won't floww well over to the far cylinder. if you can see the valve shfting back & forth inside the hopper, that it much too low.

Either you let the material level fall too far & it got a good gulp of air, or the mud is too stiff, and it isn't flowing too well into the cylinders. Some pumpers figure they gotta be heroes and pump real fast, so stiff mud doesn't get a chance to fall by gravity to get sucked into the cylinders. (kinda like the truck driver mentality that you gotta get to the jobsite at the same time as the truck that left 10 minutes ahead.) The job always goes better if you can keep it slow & steady. Most pumps are paid by the hour & by the yard too, so might as well use the time. Besides pumping fast accelerates the wear of the pipes & elbows by up to 3 times.

The newer pumps with the bigger re-mixers/agitators will feed the cylinders better than older ones with smaller, slower agitators. A 4 to 5 inch slump feeds really nice, when you get down to 2-3 inch it always sucks a little air though the rock matrix in the hopper, even when pumping slow. But sometimes the job requires the stiff mixes for whatever reason.

Air ingestion is dangerous for the personnel at the end of the hose, if there is a good volume of compressed air in the lines and there is a momentary plug, it will easily pressurize the air pocket to 800+psi, and when it lets go, all that stored energy comes out ALL AT ONCE with the force of a rocket. I've seen a 280 lb man lifted 4' of the ground and thrown 20 feet, NOT GOOD.

It's called hose whipping & it can happen on small trailer pumps too. Every bit as dangerous, because some of those small pumps can develop more pressure on the concrete that the big, high-volume pumps.

People have been blinded, maimed, disfigured and killed by hose-whipping, it's not to be taken lightly.

TRY NOT TO LET IT HAPPEN!! Ask the pump operator where the E-stop is so that if it does get a big gulp of air, you can stop the machine. Then the operator can reverse the pump to expel the trapped air back into the hopper. If he's up on the 3rd floor, he may want you to re-set the E-stop so he doesn't have to come all the way back to the pump to do it himself. But get the instructions from him first.

A vibrator on the grate and/or hopper will help in getting the mud to flow too. Ask the pumper about vibrator functions. They can control them from the remote on the new models.

Working with pumps 101 class #1 is dismissed!! ;~)

[batchmaster]

"Also it is IMPERATIVE that the hopper be kept relatively full, so that it doesn't suck any air. This can result in some severe injuries or death at the other end, in the event of a plug & release. At the very least it is messy."

that's all you said about keeping the hopper full, i'm just the dispatcher in here, never seen a pump actually run, have shipped to plenty of pumps but...

so now i gotcha, thanks for the pumps 101 class...

[Driver]

Is some good info there Speedy for the guys that arnt around Pumps alot....
I know its know laughing matter,,I seen em blow and shake before,,I dont even like walking along side a hose thats on the ground (but we all do it) Just like the super single tires (or any tire for that matter),,could cut a man in half if it blows while ya are standing there

[speedy]

Here's a link to a PDF file from the ACPA (American Concrete Pumping Association) that throws a little more light on the subject....explains what is going on inside the system as the air is moving through it.

www.concretepumpers.com/pdfs/hosewhip_bulletin.pdf

If you have any questions about pumps, ask away, I'll tell you what I know, or find the answer. I haven't worked around high-rise pumping with the big trailer pumps, but I know the pressures involved are higher.

[batchmaster]

okay, now this pretty much talks about hose whip when the pump sucks a gulp of air...is this the same case of what happens when it shoots concrete out of the hopper or is this something else? maybe the operator knows he has sucked some air and backs the concrete back out to get rid of the air?

[Driver]

My money is on the Hopper got to low.. (just cause Ive seen it)But will wait for Speedy's answer.And thats assuming Batchmaster is still referring to Backfiring term?


:'(I cant open that link to hose whipping,,Keeps telling me it not a PDF file....its either my dial-up or because I don't let Abobe update when it asks??
And I want to read it,,,,oh well Will try to sneak into the office computer where they got that fancy HIGH SPEED city connection

[batchmaster]

yeah, backfiring out of the hopper.

[speedy]

When the hopper 'BURPS' at you, it is because the hopper got too low, and it sucked in some air, and some of that compressed air escaped during the valve changeover.

Some of you may have never actually seen the valve hidden under the mud. Here's a picture of mine. It's called a 'Long Rock Valve', and it's exclusive to Schwing, all the other pumps have an S-Tube Valve.

Here's the Schwing Valve:


Here's a picture of a Putzmeister S-Tube:

Other valve types are 'Gate Valves' - they generally have the discharge pipe coming up and over the hopper, and Some Putz's have whats called the 'Elephant Trunk' that comes right out of the middle of the hopper - not too common in North America.


If the spec calls for a low slump, it it tough to keep it from burping, because the mud doesn't want to flow into the cylinders as fast as the cylinders want it. The operator should slow the pump down some in that case. It may help to keep the chute closer to the center & to the front of the hopper. The vibrator on the grate or hopper will help also.

[Driver]

I've seen pump trucks that dont keep the vibrator in working order.
Or a horn that gives me a lil advance notice that he is shutting down or starting back up.Horns help alot whiling dumping at a high rate,,, and now its my fault that the hopper is over flowing either at end of job or while opertor is booming up or down,(moving)
Its funny how the lil stuff can make a job go good or bad no matter what kind of equipt. is being used..

[batchmaster]

speedy, now that is a great picture and post to let guys know what actually goes on inside the hopper. like i said, i've never been around a pump to see it operate, these pics and info from the post really help to understand what's going on. thanks!

[speedy]

I think most guys are mechanically-minded enough to figure out how the hopper end works. The vave shifts back and forth under the hopper full of mud to allow the open cylinder to suck in the mud, while the other is pushing it's load out into the pipline.

That part is pretty basic, the complicated stuff is the hydraulic system to get it all going on at the right time.

The intakes to the cylinders are generally 9" in Dia, which is what my pump is, although there are some monsters out there that are 11" and even 12" and the length of stroke on mine is 79", but again the monsters are 80" and up. mine will do 22 strokes per minute, the monsters, 36 strokes. They claim an output of 250 to 300 yph, but it's tough to feed them that fast.

You can see how easy it is to suck air if it's cranked up. Some guys like to pump like heroes, but a steady pace is best. no point swamping the placing crew and stopping all the time, not to mention the danger of hose-whipping due to ingested air. Besides, pumping fast just wears the pipes out faster, anything over 100 yph is really eating up the profits, especially when a steady 60 or so will do the job just as well, besides the pump is probably there on an hourly rate.

[concretejoe]

speedy said:

Air ingestion is dangerous for the personnel at the end of the hose, if there is a good volume of compressed air in the lines and there is a momentary plug, it will easily pressurize the air pocket to 800+psi, and when it lets go, all that stored energy comes out ALL AT ONCE with the force of a rocket. I've seen a 280 lb man lifted 4' of the ground and thrown 20 feet, NOT GOOD.

It's called hose whipping & it can happen on small trailer pumps too. Every bit as dangerous, because some of those small pumps can develop more pressure on the concrete that the big, high-volume pumps.

People have been blinded, maimed, disfigured and killed by hose-whipping, it's not to be taken lightly.

So true. There was a guy killed in Louisville not too long ago. He got knocked off the third floor of a building by the hose. His son-in-law was standing next to him when it happened.

[BillyCement]

I have no problem giving water to a pump operator. In fact, he can have all my water. All I ask is that he waits until I'm done washing down my truck. Then he can have all the water I have left. That sounds reasonable enough, but I've heard complaints from pump guys because they want the water when they want the water. Not when I'm ready to give it to them. I get along fine with 95% of the pump guys I work with, but there's a few who just won't listen to reason.

[hicups]

I think most guys are mechanically-minded enough to figure out how the hopper end works. Not this one, Im not a guy and I'm really really not mechanically-minded...I just drive...and yall think Im lying ask the guys I work with...LOL..

[gant]

they can have my water when I'm finished with it.. like I tell everyone be nice and and wait your turn or I'll magically use it all up while I'm washing down.. and when i feel someone is using too much of it I walk over to them and I have a serious look on my face and ask them to look under the truck.. and ask if they see a well under it.. then they get the hint

[BillyCement]

gant said:

they can have my water when I'm finished with it.. like I tell everyone be nice and and wait your turn or I'll magically use it all up while I'm washing down.. and when i feel someone is using too much of it I walk over to them and I have a serious look on my face and ask them to look under the truck.. and ask if they see a well under it.. then they get the hint

I agree with everything you said, Gant. I like that line about not having a well.

[Ideal Driver]

Yea that line about the well is awesome. I'll have to remember that one.

[Crazy Mudder Trucker]

May 29, 2006 6:20:48 GMT -5 Driver said:

I've seen pump trucks that dont keep the vibrator in working order.
Or a horn that gives me a lil advance notice that he is shutting down or starting back up.Horns help alot whiling dumping at a high rate,,, and now its my fault that the hopper is over flowing either at end of job or while opertor is booming up or down,(moving)
Its funny how the lil stuff can make a job go good or bad no matter what kind of equipt. is being used..

horns a big plus! sucks when there is no horn and you overflow the hopper...fix your horn meng!!

[LEAD DOG]

Jul 2, 2008 20:57:58 GMT -5 Crazy Mudder Trucker said:

May 29, 2006 6:20:48 GMT -5 Driver said:

I've seen pump trucks that dont keep the vibrator in working order.
Or a horn that gives me a lil advance notice that he is shutting down or starting back up.Horns help alot whiling dumping at a high rate,,, and now its my fault that the hopper is over flowing either at end of job or while opertor is booming up or down,(moving)
Its funny how the lil stuff can make a job go good or bad no matter what kind of equipt. is being used..

horns a big plus! sucks when there is no horn and you overflow the hopper...fix your horn meng!!

YEAH!!! FIX YER HORN MISTER!!!

[Mort]

Jul 2, 2008 21:58:12 GMT -5 LEAD DOG said:

Jul 2, 2008 20:57:58 GMT -5 Crazy Mudder Trucker said:

horns a big plus! sucks when there is no horn and you overflow the hopper...fix your horn meng!!

YEAH!!! FIX YER HORN MISTER!!!

I love that when their horn doesn't work (or isn't there), they don't hear you winding the engine up, and you hit the e-stop because they're about to suck air, and they get mad at you. I'd reset it, but every time I do, they think its a problem with their control box and they keep on pumping.

But I digress.

[gant]

every pump job we are on there is always a laboror on the back of the pump so I dont have to worry about it..but alot of the times the laboror is jacking off somewhere not doing his job but the operator usually sees im out..