Blog posts tagged with 'cool cell'

In our blog post highlighting Hog Slat’s engineering department (see Engineering Grower Select) Frank remarked, “In almost every case we can look at existing products and make improvements.”

The GrowerSELECT® Curtain Machine is a great example of making changes to existing products to improve performance and reduce maintenance.

If you have ever “hung” a curtain machine, you will appreciate this feature. After placing a lag bolt in the wall about ½” short of flush, you simply hang the machine from a single keyhole slot in the back of the cabinet. It is much easier to level and add the four mounting lag bolts because the unit remains supported.

The Curtain Machine includes three sealed ball bearing head pulleys instead of two.  The extra pulley is added to increase the choices for installing the main cables.  Use the two outside pulleys to cable the machine on both sides of the building.  Single-sided installations have the off side cable routed through the top pulley.

One of the highest mortality items on a screw type machine is the load block.  Other curtain machines use bronze, brass or nylon. However, the GrowerSELECT machine utilizes a self-lubricating, low friction acetal plastic for both the insert nut and load block slides.   For a more in-depth comparison see our blog post, “More Than You Ever Wanted to Know about Curtain Machine Load Blocks.”

The Curtain Machine features dual limit switches.  The primary limit switches set the travel length, with secondary or redundant switches backing these up. If the first switch fails and engages the secondary switch, the machine shuts down and must be serviced before operating again.  Also included is an auxiliary switch, used to activate a fan after the curtain closes.  Other brands charge extra for this feature.

Another feature you will appreciate is the local control switches, standard with the GrowerSELECT Curtain Machine.   A toggle switch sets the machine in manual and overrides the ventilation control.  This is a great safety feature that prevents anyone from activating the unit while it is being serviced.  In addition, it certainly makes it easier to set the limit switches compared to performing this task from a remote controller.

Eventually, any curtain machine will have to be serviced, and this is where the GrowerSELECT Curtain Machine shines.  Note the cutouts in the galvanized housing. You can slip the entire motor assembly out of these slots after loosening three mounting bolts.  It is much easier to service the motor outside of the cabinet.

The entire screw assembly will also come out through these cabinet slots.  It’s still a big job, but it’s possible to slide the entire assembly out for servicing rather than dismantling the screw inside the cabinet.

Although not groundbreaking, the GrowerSELECT Curtain Machine is an example of Hog Slat’s commitment to engineering better products.  Click on Curtain Machine for pricing and ordering information.

Nearly all of Hog Slat’s competitors try to dismiss the GrowerSELECT® product line as “just a cheap copy.” However, every time I work with Hog Slat’s engineering department I realize how misguided this perception is.  Nothing is ever “just copied.”

I was quizzing Hog Slat engineer, Tim King, about the features and benefits of GrowerSELECT’s Curtain Machine.   He explained to me that one of the highest replacement items on a screw type machine is the load nut. As the load block moves up and down the Acme screw, the friction generated causes the insert to fail.  If friction is reduced, wear and maintenance of the insert is reduced.

1. Grower Select – Aluminum Block/Acetal Insert
2. Brass Block
3. Aluminum Block/ Brass Insert
4. Steel Block/ Nylon Insert

For the GrowerSELECT Curtain Machine, Tim selected acetal plastic to be used for the insert and cabinet slides.  Acetal is one of the strongest non-reinforced plastic available to replace metal bushings.  It is able to reduce friction within the curtain machine because of its low friction coefficient.  So why is this plastic a better choice than the brass or nylon inserts shown in the pictures?

To get a better understanding of Coefficients of Friction, consider these ratings of various materials used for bearings.

Steel on steel dry contact is .80, if you apply grease it becomes .16

Brass on steel dry contact is .35, grease it and it is now .19

Nylon on steel dry contact is .25 and with lubrication moves to .15

Acetal on steel dry rating is .15.

1. Nylon
2. Grower Select Acetal
3. Brass block
4. Brass insert

These ratings aren’t telling anyone anything they didn’t already know. Keep a bearing greased, and it will last a long time. What is interesting though is the rating for an acetal load nut without grease is the same as any of other insert materials with grease.

As a matter of fact, the acetal load nut does not even have a grease zerk.  However, we still recommend greasing the Acme shaft with general purpose Lithium grease, primarily to prevent surface rust on the shaft.

I wish you could put your hands on the four inserts in the picture.  The acetal has a slippery, almost oily feel to it; different than the nylon insert.  It is a denser, heavier plastic that is less brittle compared to nylon.

The real advantage is in the day-to-day maintenance on your farm.  The best intentions (like greasing a curtain machine) get lost in the bustle of all the work.  Why not choose a curtain machine with features that reduce maintenance?   Click on Curtain Machine for more information.

We spoke with Hog Slat engineers, Tyler Marion and Tim King about the differences between using a jet or submersible pump to fill evaporative cooling systems. Here’s a quick synopsis of our discussion.

1) Jet pumps are more reliable because they can run dry for a period of time. For instance, if you discover during morning chores a leak occurring overnight had drained the system, a jet pump would still be working.   A submersible pump that runs that long without water will need to be replaced.

2) Jet pump repairs are less costly. The impeller and motor are two individual components; a bad motor can be replaced separately. Submersible pumps are a single unit.

3) Jet pump repairs and service are easier. A jet pump system is all above ground…a submersible pump must be pulled from the sump for repairs. A drain plug on the GrowerSELECT jet pump allows easy access for service and winterizing.

4) The integrated trash basket on a jet pump protects the pump from debris.

5) Submersible pumps are designed to move waste water from underground applications; low volumes with high head pressures. Jet pumps are a better choice for evaporative cooling applications as they move larger volumes of water at reduced head pressures.

6) One of the advantages cited for using a sump/submersible pump system is the sump acts as an extra reservoir for the system. The bottom trough of an 80′ long system holds about 300 gallons of water. A typical sump only holds about 30 gallons; really an insignificant amount. The main purpose of a sump area is to provide a place where a submersible pump can run in water so it doesn’t burn up. (see 1.)

To order go to jet pump