Grinding submersible pump in cast-iron for sewage water, 2 poles, 3.7kW,
Max head: 32 m,
Max capacity: 320 L/min



The grinder pumps are provided with a cutting system able to chop up paper, little ropes, towels, napkins, leather, objects in plastic, rubber, lattex or other fibrous parts present into the sewage water. The grinding pumps are required when the delivery pipes are so narrow that a solid part could clog the pipe itself or when it is needed a pump for sewage water but with an high head. The pumps series GRINDER 500 must always be connected to a control box including a manual reset amperometric protection: this kind of protection is necessary to avoid that the motor can get burnt in case a too hard solid part blocks the cutting system.


The GRINDER 500 is very professional and it is usually installed in hospitals, camping, restaurants and hotels. This model cannot be used to pump water containing stones nor hard solid parts (e.g. pieces of wood or metal) nor straw.

Operation conditions

Max liquid temperature: 50 °C (122 °F)

pH: 6-10

Max density < 1100 kg/m³

Max immersion depth: 30m



Performance curve:


Model                                Head (m)                              
8 12 16 20 24 28 32
GRINDER 500  L/min   320  287 260 219 163 100   0  
m3/h 19,2 17,2 15,6 13,1 9,8 6,0 0
L/s 5,33 4,78 4,33 3,65 2,72 1,67 0



Technical characteristics:

Outlet 2" - DN 50 vertical flanged with threaded counterflange
Solid passage ---
Cutting system Composed by a fix cutting ring and a rotating knife
Impeller Back open impeller "vortex" type.
Mechanical seal Double mechanical seal in oil chamber. The lower one in silicum carbide / silicum carbide / NBR, the upper one in allumina / graphite / NBR + NBR oil seal.
Motor Dry. Insulation class: F.
Motor protection Automatic reset built-it thermal protection. Anyway the pump must be connected to a fused remote isolator switch at customer's care (see optional electric board).

The pump is supplied without float-switch


10 meters cable H07RNF 4G2.5 without plug

Capacitor -
IP 68



Electric characteristics:

Model Power Nos. poles R.p.m. Voltage Ampere
GRINDER 500 5.0 HP - 3.7kW 2 2850 400V/50Hz/3 8,2 A




Cutting system    Stainless steel AISI 440 tempered                                    
Impeller Cast-iron GG 25                                                             
Pump cover Cast-iron GG 25
Motor case Cast-iron GG 25
Pump body Cast-iron GG 25
Pump support Cast-iron GG 25
Motor shaft Stainless steel AISI 403
Packing set NBR



Weight and dimensions:

Model Voltage Outlet             Dimensions (mm)                Weight 
female threaded A B C D E (kg)
GRINDER 500  400V/50Hz/3  2" - DN 50 616 393 500 290 660 53





Professional straight brass connection 2" in three pieces

No-return valve Professional ball check valve threaded 2" in cast-iron
Float-switch 10 or 20 metres cable float-switch to be connected to an electric board
Electric board The model GRINDER 500 must necessarly be connected to an electric board with an amperometric protection (as the model F6-0.5/10-3). This kind of protection is necessary for grinder pumps to avoid that the motor can get burnt in case a too hard solid part blocks the cutting system.



GRINDER 500 ENG - REV. 2.0 - 03/12/2018

Comex Srl Società Unipersonale, Via delle Industrie, 42 - 31057 Silea (TV) - ITALY
P.I.: 00345210264 - Cap. Soc.: 50.000€ i.v.