How can I make this work?????????

[Mvillines]

The suggestion is to have one door exclusively for entering only and difficult for exiting or designed where you could not exit. Careful not to violate any building or safety codes. The other doors would be for exiting only and wired to de-energize the blower. Install signage for the appropriate door.

 

[Doug S.]

I was going to post this earlier as an alternative to inside the booth options... but ran out of time.


You could add a control relay, and try this... the buttons turn the fan on and off. If the door is open the fan is off, until the door is closed.

(Yea the drawing is hokey, but I was in a hurry and thats what 2 min in MSpaint gets ya)

I would verify that the setup I'm suggesting is legal as far as safety code goes.

Regards,
Doug S.

 

[billsnuff]

Fwiw

Fwiw

i would series the STOP ahead of the START, otherwise a failure could mean always on. JMSHO

 

[alfiesauce]

The issue with Dougs is that as soon as the door closes again then the fan starts up again, which the way I'm reading it is not supposed to happen.

What about a time off delay timer (I think off delay - time starts on break and then maintains contact until X amount of seconds) on the doors? So that they can start the fan up but if the doors stay open for more then say 10 seconds then the fan shuts down.
This setup would allow them to start the motor with their start/stop station, the fan would start up, they could walk in as normal and the system would still run smoothly with proper airflow. If someone proped the door open or if it didn't close correclty, after 10 seconds the fan would shut down and then the system would have to be restarted from the start/stop station again.

---
I was rereading original post - if the door contacts are Open when the door is closed then you would need to do a "time starts on make" instead of time starts on break...

 

[Vod-Vil]

Install a Hand/Off/Auto switch next to the Stop/Start station.In the Hand mode the the Stop/Start station will control the fan.In Auto mode the fan will be controlled by the door switches.

 

[Doug S.]

billsnuff is correct. I was in a hurry, the way was drawn would be a bad decision. Drawing changed.

The issue with Dougs is that as soon as the door closes again then the fan starts up again, which the way I'm reading it is not supposed to happen.

Oops, I figured that's what they were after...

I hearby retract my circuit diagrammed idea, and suggest a mirror, a long stick with loop on the end, and a small hole in the wall. Let your imagination take it from there. :grin:

Doug S.

 

[brother]

I was thinking of something 'similar to "Doug S." but a little different (assuming I understand what you want forgive me if I dont).

I forget the name of the type of the control relays, but they are used in ligthing alot where you have to momentary switch to turn on/off the lights, (the relay stays in the position that its switched in wheather its on or off)

You can wire a 'magnetic sensing switch' like they use alot in 'security' for windows and doors that can be wired in parralled (on the off/deenergizing side) with the controling relay for the fan or some other 'momentary contact' tied into the door when it opens the fan stops.

Is there really a need for the e-stop?? if so just wire it in series of the 'power' to the fan. Hope my description makes sense.

 

[billsnuff]

stepping relay?

stepping relay?

I forget the name of the type of the control relays, but they are used in ligthing alot where you have to momentary switch to turn on/off the lights, (the relay stays in the position that its switched in wheather its on or off)

each time the momentary is pushed, it goes from on to off, etc.

 

[iwire]

What's missing?

The fan would stay on when they open the door to leave the bay.

 

[pfalcon]

How about:
Replace the pushbutton On/Off with a selector switch On/Off.
Set it to ON when you want the doors to control the fan.
Set it to OFF when you don't want the fan.

For energy conservation you can add a timer to the circuit that limits how long the fan can run unattended.

 

[LarryFine]

The fan would stay on when they open the door to leave the bay.

Not with the door switch(es) in series with the manual switch, which is what I suggested.

 

[iwire]

Not with the door switch(es) in series with the manual switch, which is what I suggested.

You lost me, if the door switches are in series with the manual switch how is the fan going to run when they go in the doors?

I have been staying out of making suggestions here only because I don't think modifying a paint spray both controls is something I would take on. That pesky risk of explosion tends to make me cautious.:smile:

 

[Flex]

Install a PLC

 

[chevyx92]

I have been staying out of making suggestions here only because I don't think modifying a paint spray both controls is something I would take on.

This came about from an OSHA visit. Existing spray booth has 2 big main doors and a side man door. Has typical fluorescent lights on the outside shining in and a 3 phase exhaust fan controlled by a start/ stop controller which controls a contactor with latching contacts. OSHA said they need to bring booth up to current codes or fines are coming! Owner of booth told us that they need the booth doors when opened to STOP the exhaust fan. Doors can not be the control means. (example if doors are opened if there was a fire in booth and then doors were closed again the fan would start back up and thats not their intent). There must be a manual reset. They are also making them install a fire supression system in the booth as well as they need an air pressure switch on air line so all air is cut to booth. I know newer booths have a PLC control box that does all this. We were asked to make this happen on an existing booth. We are now trying to find an appropiate control box if we can.

 

[LarryFine]

Doors can not be the control means. (example if doors are opened if there was a fire in booth and then doors were closed again the fan would start back up and thats not their intent). There must be a manual reset.

"Oh. Never mind."​

 

[LarryFine]

So, if one has to turn on the exhaust first, how do they get in the booth without turning the blower off?

 

[chevyx92]

"oh. Never mind."​

lol !

 

[chevyx92]

So, if one has to turn on the exhaust first, how do they get in the booth without turning the blower off?

Thats my problem!!!!!!!! Only thing I can come up with is a delay on timer to give them enough time to get in and close the door to complete the circuit or install a start button in booth (explosion proof of course).

 

[LarryFine]

Thats my problem!!!!!!!! Only thing I can come up with is a delay on timer to give them enough time to get in and close the door to complete the circuit or install a start button in booth (explosion proof of course).

One more question: is it okay if the fan is already on while entering the booth, or must the painter be inside before startup?

 

[chevyx92]

One more question: is it okay if the fan is already on while entering the booth, or must the painter be inside before startup?

They need the option to start it when needed. Sometimes they do sanding there and they don't want the fan running but yet the doors will be closed. They only need fan running when painting and want the safety of doors shutting fan when opened.