3 replies to this topic

[jprocess]

Dear All,
What is the function of jockey firewater pump in comparison with main firewater pump?Why does this pump called "jokey"?
Also as you know firewater pumps are diesel operated.How a diesel operated pump works?
Thanks in advance.
Cheers.

[palusa]

Jprocess,

1) A 'jockey pump(s)' is in general used to keep pressurized a f/w ring main. The design flow of this pump is 10-50 m3/h and design head abt. 2 bar above the main fire pumps switch-on so to compensate f/w ring leaks without starting up the main pumps.

Shell-DEP 80.47.10.31 design basis for the jockey pump:

The ring main shall be kept pressurised at typically 2 to 3 bar (ga).
If a jockey pump is used to keep the ring mains pressurized, it shall be backed up by a spare jockey pump; both pumps shall have a capacity of 15 m3/h to compensate for leakages.
If the jockey pumps are also to be used for providing plant service water, then each pump shall have a capacity of at least 30 m3/h. In all cases the pressurizing
facilities shall be designed for the discharge pressure of the fire water pumps.

The JP could be kept in continuous service with minimum flow open to FW tank; this prevents switching on-off to compensate leakages. Alternatively, the f/w main is kept pressurized with N2 accumulator and JP starts at abt. 95% of the normal pressure level.


2) Normally the FW main pump(s) is electrical motor driven (because of ease and quick start-up) while spare pump(s) is diesel-motor operated. The DE is started either through a compressed air device or batteries. DE has normally an oil running tank sized for the same FW tank reserve (but min 6 hrs).

Refer for (many) other important prescriptions to NFPA 20.


Hope this helps.
_Lf_

[Padmakar Katre]

Dear All,
What is the function of jockey firewater pump in comparison with main firewater pump?Why does this pump called "jokey"?
Also as you know firewater pumps are diesel operated.How a diesel operated pump works?
Thanks in advance.
Cheers.

Hello sir,
Jokey pumps are for to keep the fire water network always pressurized these pumps always running and keep the system running and maintain system pressure around 7-8 kg/cm2 and all other pumps are (electrical motor driven) are on auto-start as soon as some opens fire hydrant and start using water for any purpose and the network prussre starts droping the other pumps which are on auto-start they are provided a logic i.e. a certian valuve of the pressure to so that it wiil get start automaticaly now in our system there 2 jokey pumps only one is running and the all other one another jokey plus 5 pumps electrical motor driven and two diesel opearted pumps now every pump among the electrical operated has a certain pressure setting as soon the network pressure comes down the next pump will start now we have total nos. of fire hydrant are 164 if all these are opened at the same time still we will have more tan 5.5 kg/cm2 prusee in the network.
I hope i had explaine you the total working of the fire network along with jockey pumps.

[gvdlans]

You also asked why this pump is called "jockey pump". The answer can be found on http://www.accessmyl...286-6811433_ITM

"What is a jockey pump and why does it carry that title? Picture a horse race. There is a small guy riding on top of (or above) a large horse. That small guy on the horse is referred to as a jockey. On a fire protection system requiring a fire pump, there is a small pump that maintains pressure above the pressure settings of the larger fire pump. Hence the name "jockey pump." The purpose of a jockey pump is to maintain pressure in a fire protection piping system so the larger fire pump does not need to run. A jockey pump package consists of a pump, motor and controller. "